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New submissions for Tue, 3 Dec 19

[1]  arXiv:1912.00026 [pdf, ps, other]

Title: Synchrotron spectra of GRB prompt emission and pulsar wind nebulae

Authors: Siyao Xu

Comments: 8 pages, 6 figures, conference proceedings paper for the 18th Annual International Astrophysics Conference (February 18-22, 2019, Pasadena, CA, USA)

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Plasma Physics (physics.plasm-ph)

Particle acceleration is a fundamental process in many high-energy astrophysical environments and determines the spectral features of their synchrotron emission. We have studied the adiabatic stochastic acceleration (ASA) of electrons arising from the basic dynamics of magnetohydrodynamic (MHD) turbulence and found that the ASA acts to efficiently harden the injected electron energy spectrum. The dominance of the ASA at low energies and the dominance of synchrotron cooling at high energies result in a broken power-law shape of both electron energy spectrum and photon synchrotron spectrum. Furthermore, we have applied the ASA to studying the synchrotron spectra of the prompt emission of gamma-ray bursts (GRBs) and pulsar wind nebulae (PWNe). The good agreement between our theories and observations confirms that the stochastic particle acceleration is indispensable in explaining their synchrotron emission.

[2]  arXiv:1912.00031 [pdf, ps, other]

Title: Multi-scale dynamics in star-forming regions: the interplay between gravity and turbulence

Authors: A. Traficante, G. A. Fuller, A. Duarte-Cabral, D. Elia, M. H. Heyer, S. Molinari, N. Peretto, E. Schisano

Comments: 15 pages, 18 figures, 2 tables. Accepted for publication in MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA)

In this work we investigate the interplay between gravity and turbulence at different spatial scales and in different density regimes. We analyze a sample of 70 $\mu$m quiet clumps that are divided into three surface density bins and we compare the dynamics of each group with the dynamics of their respective filaments. The densest clumps form within the densest filaments on average, and they have the highest value of the velocity dispersion. The kinetic energy is transferred from the filaments down to the clumps most likely through a turbulent cascade, but we identify a critical value of the surface density, $\Sigma\simeq0.1$ g cm$^{2}$, above which the dynamics changes from being mostly turbulent-driven to mostly gravity-driven. The scenario we obtain from our data is a continuous interplay between turbulence and gravity, where the former creates structures at all scales and the latter takes the lead when the critical surface density threshold is reached. In the densest filaments this transition can occur at the parsec, or even larger scales, leading to a global collapse of the whole region and most likely to the formation of the massive objects.

[3]  arXiv:1912.00034 [pdf, other]

Title: The Structure and Stability of Extended, Inclined Circumplanetary Disk or Ring Systems

Authors: Jessica Speedie, J. J. Zanazzi

Comments: 12 pages, 8 figures, submitted to MNRAS

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

Large dips in the brightness for a number of stars have been observed, for which the tentative explanation is occultation of the star by a transiting circumplanetary disk or ring system. In order for the circumplanetary disk/rings to block the host star's light, the disk must be tilted out of the planet's orbital plane, which poses stability problems due to the radial extent of the disk required to explain the brightness dip durations. This work uses N-body integrations to study the structure and stability of circumplanetary disk/ring systems tilted out of the planet's orbital plane by the spinning planet's mass quadrupole. Simulating the disk as a collection of test particles with orbits initialized near the Laplace surface (equilibrium between tidal force from host star and force from planet's mass quadrupole), we find that many extended, inclined circumplanetary disks remain stable over the duration of the integrations (~3-16 Myr). Two dynamical resonances/instabilities excite the particle eccentricities and inclinations: the Lidov-Kozai effect which occurs in the disk's outer regions, and ivection resonance which occurs in the disk's inner regions. Our work places constraints on the maximum radial extent of inclined circumplanetary disk/ring systems, and shows that gaps present in circumplanetary disks do not necessarily imply the presence of exomoons.

[4]  arXiv:1912.00038 [pdf, other]

Title: Spitzer + VLTI-GRAVITY Measure the Lens Mass of a Nearby Microlensing Event

Authors: Weicheng Zang, Subo Dong, Andrew Gould, Sebastiano Calchi Novati, Ping Chen, Hongjing Yang, Shun-Sheng Li, Shude Mao, K.B. Alton, Sean Carey, G. W. Christie, F. Delplancke-Ströbele, Dax L. Feliz, J. Green, Shaoming Hu, T. Jayasinghe, R. A. Koff, A. Kurtenkov, A. Mérand, Milen Minev, Robert Mutel, T. Natusch, Tyler Roth, Yossi Shvartzvald, Fengwu Sun, T. Vanmunster, Wei Zhu

Comments: 3 Figures and 6 Tables Submitted to AAS Journal

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)

We report the lens mass and distance measurements of the nearby microlensing event TCP J05074264+2447555. We measure the microlens parallax vector ${\pi}_{\rm E}$ using Spitzer and ground-based light curves with constraints on the direction of lens-source relative proper motion derived from Very Large Telescope Interferometer (VLTI) GRAVITY observations. Combining this ${\pi}_{\rm E}$ determination with the angular Einstein radius $\theta_{\rm E}$ measured by VLTI GRAVITY observations, we find that the lens is a star with mass $M_{\rm L} = 0.495 \pm 0.063~M_{\odot}$ at a distance $D_{\rm L} = 429 \pm 21~{\rm pc}$. We find that the blended light basically all comes from the lens. The lens-source proper motion is $\mu_{\rm rel,hel} = 26.55 \pm 0.36~{\rm mas\,yr^{-1}}$, so with currently available adaptive-optics (AO) instruments, the lens and source can be resolved in 2021. This is the first microlensing event whose lens mass is unambiguously measured by interferometry + satellite parallax observations, which opens a new window for mass measurements of isolated objects such as stellar-mass black holes.

[5]  arXiv:1912.00057 [pdf, other]

Title: The Evolution of Gamma-ray Burst Jet Opening Angle through Cosmic Time

Authors: Nicole Lloyd-Ronning, Valeria U. Hurtado, Aycin Aykutalp, Jarrett Johnson, Chiara Ceccobello

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

Jet opening angles of long gamma-ray bursts (lGRBs) appear to evolve in cosmic time, with lGRBs at higher redshifts being on average more narrowly beamed than those at lower redshifts. We examine the nature of this anti-correlation in the context of collimation by the progenitor stellar envelope. First, we show that the data indicate a strong correlation between gamma-ray luminosity and jet opening angle, and suggest this is a natural selection effect - only the most luminous GRBs are able to successfully launch jets with large opening angles. Then, by considering progenitor properties expected to evolve through cosmic time, we show that denser stars lead to more collimated jets, and argue that the observed anti-correlation between opening angle and redshift can be accounted for if lGRB massive star progenitors at high redshifts have higher average density compared to those at lower redshifts. This may be viable for an evolving IMF, and under the assumption that average density scales directly with mass, this relationship is consistent with the form of the IMF characteristic mass evolution suggested in the literature. The jet angle-redshift anti-correlation may also be explained if the lGRB progenitor population is dominated by massive stars at high redshift, while lower redshift lGRBs allow for a greater diversity of progenitor systems. Overall, however, we find both the jet angle-redshift anti-correlation and jet angle-luminosity correlation are consistent with the conditions of jet launch through, and collimation by, the envelope of a massive star progenitor.

[6]  arXiv:1912.00065 [pdf, other]

Title: Rotation method for accelerating multiple-spherical Bessel function integrals against a numerical source function

Authors: Zachary Slepian, Yin Li, Marcel Schmittfull, Zvonimir Vlah

Comments: 21 pages, 14 figures, submitted MNRAS; code available at this https URL

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Instrumentation and Methods for Astrophysics (astro-ph.IM)

A common problem in cosmology is to integrate the product of two or more spherical Bessel functions (sBFs) with different configuration-space arguments against the power spectrum or its square, weighted by powers of wavenumber. Naively computing them scales as $N_{\rm g}^{p+1}$ with $p$ the number of configuration space arguments and $N_{\rm g}$ the grid size, and they cannot be done with Fast Fourier Transforms (FFTs). Here we show that by rewriting the sBFs as sums of products of sine and cosine and then using the product to sum identities, these integrals can then be performed using 1-D FFTs with $N_{\rm g} \log N_{\rm g}$ scaling. This "rotation" method has the potential to accelerate significantly a number of calculations in cosmology, such as perturbation theory predictions of loop integrals, higher order correlation functions, and analytic templates for correlation function covariance matrices. We implement this approach numerically both in a free-standing, publicly-available \textsc{Python} code and within the larger, publicly-available package \texttt{mcfit}. The rotation method evaluated with direct integrations already offers a factor of 6-10$\times$ speed-up over the naive approach in our test cases. Using FFTs, which the rotation method enables, then further improves this to a speed-up of $\sim$$1000-3000\times$ over the naive approach. The rotation method should be useful in light of upcoming large datasets such as DESI or LSST. In analysing these datasets recomputation of these integrals a substantial number of times, for instance to update perturbation theory predictions or covariance matrices as the input linear power spectrum is changed, will be one piece in a Monte Carlo Markov Chain cosmological parameter search: thus the overall savings from our method should be significant.

[7]  arXiv:1912.00075 [pdf, ps, other]

Title: Triggering nuclear and galaxy activity in the Bullet cluster

Authors: S. Puccetti, F. Fiore, A. Bongiorno, K. Boutsia, R. Fassbender, M. Verdugo

Comments: 28 pages, accepted for publication in the A&A

Subjects: Astrophysics of Galaxies (astro-ph.GA)

The analysis of the cluster environment is a valuable instrument to investigate the origin of AGN and star-forming galaxies gas fuelling and trigger mechanisms. To this purpose, we present a detailed analysis of the point-like X-ray sources in the Bullet cluster field. Thanks to $\sim600$ ks Chandra observations, we produced a catalogue of 381 X-ray point sources up to a distance of $\sim$1.5 virial radius and with flux limits $\sim1\times10^{-16}$ and $\sim8\times10^{-16}$ erg cm$^{-2}$ s$^{-1}$ in the 0.5-2 keV and 2-10 keV bands, respectively. We found a strong (up to a factor 1.5-2) and significant ($\ge$4$\sigma$) over-density in the full region studied $0.3R_{200}<R<1.5R_{200}$. We identified optical and infrared counterparts for $\sim$84% and $\sim$48% of the X-ray sources, respectively. We obtained new spectroscopic redshifts for 106 X-ray sources. Spectroscopic and photometric redshifts of optical and infrared sources have been also collected, and these sources were used as ancillary samples. We find that the over-density in the region $0.3R_{200}<R<R_{200}$ is likely due to X-ray AGN (mostly obscured) and star-forming galaxies both associated to the cluster, while in the more external region it is likely mostly due to background AGN. The fraction of cluster galaxies hosting an X-ray detected AGN is 1.0$\pm$0.4$\%$, nearly constant with the radius, a fraction similar to that reported in other clusters of galaxies at similar redshift. The fraction of X-ray bright AGN (L$_{2-10keV}$$>$10$^{43}$ ergs s$^{-1}$) in the region $0.3R_{200}<R<R_{200}$ is $0.5^{+0.6}_{-0.2}$$\%$, higher than that in other clusters at similar redshift and more similar to the AGN fraction in the field. Finally, the spatial distributions of AGN and star-forming galaxies, selected also thanks to their infrared emission, appear similar, thus suggesting that both are triggered by the same mechanism.

[8]  arXiv:1912.00081 [pdf, other]

Title: A DECam View of the Diffuse Dwarf Galaxy Crater II: Variable Stars

Authors: A. Katherina Vivas, Alistair R. Walker, Clara E. Martínez-Vázquez, Matteo Monelli, Giuseppe Bono, Antonio Dorta, David L. Nidever, Giuliana Fiorentino, Carme Gallart, Gloria Andreuzzi, Vittorio F. Braga, Massimo Dall'Ora, Knut Olsen, Peter B. Stetson

Comments: Accepted for publication in MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)

Time series observations of a single dithered field centered on the diffuse dwarf satellite galaxy Crater II were obtained with the Dark Energy Camera (DECam) at the 4m Blanco Telescope at Cerro Tololo Inter-American Observatory, Chile, uniformly covering up to two half-light radii. Analysis of the $g$ and $i$ time series results in the identification and characterization of 130 periodic variable stars, including 98 RR Lyrae stars, 7 anomalous Cepheids, and 1 SX Phoenicis star belonging to the Crater II population, and 24 foreground variables of different types. Using the large number of ab-type RR Lyrae stars present in the galaxy, we obtained a distance modulus to Crater II of $(m-M)_0=20.333\pm 0.004$ (stat) $\pm 0.07$ (sys). The distribution of the RR Lyrae stars suggests an elliptical shape for Crater II, with an ellipticity of 0.24 and a position angle of $153^\circ$. From the RR Lyrae stars we infer a small metallicity dispersion for the old population of Crater II of only 0.17 dex. There are hints that the most metal-poor stars in that narrow distribution have a wider distribution across the galaxy, while the slightly more metal rich part of the population is more centrally concentrated. Given the features in the color-magnitude diagram of Crater II, the anomalous Cepheids in this galaxy must have formed through a binary evolution channel of an old population.

[9]  arXiv:1912.00084 [pdf, ps, other]

Title: Stellar population properties of individual massive early-type galaxies at 1.4 < z < 2

Authors: I. Lonoce, C. Maraston, D. Thomas, M. Longhetti, T. Parikh, P. Guarnieri, J. Comparat

Comments: 23 pages, Accepted for publication in MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We analyse publicly available, individual spectra of four, massive ($M>10^{11}M_{\odot}$) early-type galaxies with redshifts in the range 1.4 < z < 2 to determine their stellar content, extending our previous work up to z~2. The wide wavelength range of the VLT/X-Shooter spectroscopic data in the UV-Optical-NIR arms along with the availability of spectro-photometry allows us to explore different techniques to obtain the stellar population properties, namely through age/metallicity sensitive spectral indices, full spectral fitting and broad-band photometric fitting. Moreover, together with the widely used optical Lick indices we consider further indices in the UV rest-frame, and demonstrate that UV indices significantly help the accuracy of the resulting population parameters.
We find galaxy ages ranging from 0.2 to 4 Gyr, where the oldest galaxy is found at the lowest redshift, with an excellent agreement between ages determined via indices, full spectral fitting or broad-band colours. These ages are in perfect agreement with ages of local galaxies at the same velocity dispersion when we assume pure passive evolution. Total metallicities derived from indices show some scatter (between less than half-solar to very high values, ([Z/H]~0.6]). We speculate on possible mechanisms explaining these values, but given the sample size and low S/N of the spectra no conclusion can be made.
Indices in the UV-rest frame generally lead to similar conclusions as optical indices. For the oldest galaxy (4 Gyr) we show that its UV-indices can only be explained by stellar population models including a UV contribution from old stellar populations, suggesting that old, UV bright populations start to inhabit mature galaxies of a few Gyr of age. This is the highest redshift (z~1.4) detection of the UV-upturn up to date.

[10]  arXiv:1912.00085 [pdf, other]

Title: An ALMA CO(2-1) Survey of Nearby Palomar-Green Quasars

Authors: Jinyi Shangguan, Luis C. Ho, Franz E. Bauer, Ran Wang, Ezequiel Treister

Comments: 17 pages, 6 figure, 4 tables, accepted for publication in ApJS

Subjects: Astrophysics of Galaxies (astro-ph.GA)

The properties of the molecular gas can shed light on the physical conditions of quasar host galaxies and the effect of feedback from accreting supermassive black holes. We present a new CO(2-1) survey of 23 z<0.1 Palomar-Green quasars conducted with the Atacama Large Millimeter/submillimeter Array. CO emission was successfully detected in 91% (21/23) of the objects, from which we derive CO luminosities, molecular gas masses, and velocity line widths. Together with CO(1-0) measurements in the literature for 32 quasars (detection rate 53%), there are 15 quasars with both CO(1-0) and CO(2-1) measurements and in total 40 sources with CO measurements. We find that the line ratio R_21 = L'_CO(2-1)/L'_CO(1-0) is subthermal, broadly consistent with nearby galaxies and other quasars previously studied. No clear correlation is found between R_21 and the intensity of the interstellar radiation field or the luminosity of the active nucleus. As with the general galaxy population, quasar host galaxies exhibit a strong, tight, linear L_IR-L_CO relation, with a normalization consistent with that of starburst systems. We investigate the molecular-to-total gas mass fraction with the aid of total gas masses inferred from dust masses previously derived from infrared observations. Although the scatter is considerable, the current data do not suggest that the CO-to-H_2 conversion factor of quasar host galaxies significantly differs from that of normal star-forming galaxies.

[11]  arXiv:1912.00094 [pdf, other]

Title: Skewness of matter distribution in clustering dark energy cosmologies

Authors: Hermano Velten, Raquel Emy Fazolo

Comments: 7 pages, 2 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA); General Relativity and Quantum Cosmology (gr-qc)

We calculate the skewness (the third moment $S_3$) of matter distribution in dynamical dark energy cosmologies. We pay particular attention to the impact of dark energy perturbations on this quantity. There is indeed a clear signature of dark energy perturbations on this quantity. By properly allowing dark energy perturbations we show that their impact on $S_3$ is strong enough (a factor $\sim 3$ greater) to easily discriminate between clustering and non-clustering dark energy cosmologies. This indicates that high order statistics of the cosmic density field are useful to the study of dark energy models and are potentially able to rule out clustering dark energy cosmologies.

[12]  arXiv:1912.00107 [pdf, ps, other]

Title: A systematic study of Galactic infrared bubbles along the Galactic plane with AKARI and Herschel. II. Spatial distributions of dust components around the bubbles

Authors: Misaki Hanaoka, Hidehiro Kaneda, Toyoaki Suzuki, Takuma Kokusho, Shinki Oyabu, Daisuke Ishihara, Mikito Kohno, Takuya Furuta, Takuro Tsuchikawa, Futoshi Saito

Comments: 20 pages, 14 figures, accepted for publication in PASJ

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Galactic infrared (IR) bubbles, which can be seen as shell-like structures at mid-IR wavelengths, are known to possess massive stars within their shell boundaries. In our previous study, Hanaoka et al. (2019) expanded the research area to the whole Galactic plane ($0^{\circ} \leq l \leq 360^{\circ}$, $|b| \leq 5^{\circ}$) and studied systematic differences in the shell morphology and the IR luminosity of the IR bubbles between inner and outer Galactic regions. In this study, utilizing high spatial-resolution data of AKARI and WISE in the mid-IR and Herschel in the far-IR, we investigate the spatial distributions of dust components around each IR bubble to discuss the relation between the star-formation activity and the dust properties of the IR bubbles. For the 247 IR bubbles studied in Hanaoka et al. (2019), 165 IR bubbles are investigated in this study, which have the Herschel data ($|b| \leq 1^{\circ}$) and known distances. We created their spectral energy distributions on a pixel-by-pixel basis around each IR bubble, and decomposed them with a dust model consisting of polycyclic aromatic hydrocarbons (PAHs), hot dust, warm dust and cold dust. As a result, we find that the offsets of dust heating sources from the shell centers in inner Galactic regions are systematically larger than those in outer Galactic regions. Many of the broken bubbles in inner Galactic regions show large angles between the offset and the broken shell directions from the center. Moreover, the spatial variations of the PAH intensity and cold dust emissivity around the IR bubbles in inner Galactic regions are larger than those in outer Galactic regions. We discuss these results in light of the interstellar environments and the formation mechanism of the massive stars associated with the IR bubbles.

[13]  arXiv:1912.00110 [pdf, other]

Title: Detection of the 511 keV Galactic position annihilation line with COSI

Authors: Carolyn A. Kierans, Steven E. Boggs, Andreas Zoglauer, Alex W. Lowell, Clio C. Sleator, Jacqueline Beechert, Terri J. Brandt, Pierre Jean, Hadar Lazar, Jarred M. Roberts, Thomas Siegert, John A. Tomsick, Peter von Ballmoos

Comments: 14 pages, 12 figures. Submitted to ApJ

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

The signature of positron annihilation, namely the 511 keV $\gamma$-ray line, was first detected coming from the direction of the Galactic center in the 1970's, but the source of Galactic positrons still remains a puzzle. The measured flux of the annihilation corresponds to an intense, probably steady, source of positron production, with an annihilation rate on the order of $\sim10^{43}$~e$^{+}$/s. The 511 keV emission is the strongest diffuse $\gamma$-ray line signal and it shows a concentration towards the Galactic center region. An additional low-surface brightness component is aligned with the Galactic disk; however, the morphology of the latter is not well constrained. The Compton Spectrometer and Imager (COSI) is a balloon-borne soft $\gamma$-ray (0.2--5 MeV) telescope designed to perform wide-field imaging and high-resolution spectroscopy. One of its major goals is to further our understanding of Galactic positrons. COSI had a 46-day balloon flight in May-July 2016 from Wanaka, New Zealand, and here we report on the detection and spectral analyses of the 511 keV emission from those observations. To isolate the Galactic positron annihilation emission from instrumental background, we have developed a technique to separate celestial signals utilizing the COMPTEL Data Space. With this method, we find a 7.2$\sigma$ detection of the 511 keV line. We find that the spatial distribution is not consistent with a single point source, and it appears to be broader than what has been previously reported.

[14]  arXiv:1912.00156 [pdf, other]

Title: Uncovering the Orbit of the Hercules Dwarf Galaxy

Authors: Alexandra L. Gregory, Michelle L. M. Collins, Denis Erkal, Erik Tollerud, Maxime Delorme, Lewis Hill, David J. Sand, Jay Strader, Beth Willman

Comments: Submitted to MNRAS. 17 pages, 14 figures

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We present new chemo--kinematics of the Hercules dwarf galaxy based on Keck II-- DEIMOS spectroscopy. Our 21 confirmed members have a systemic velocity of $v_{\mathrm{Herc}}=46.4\pm1.3$ kms$^{-1}$ and a velocity dispersion $\sigma_{v,\mathrm{Herc}}=4.4^{+1.4}_{-1.2}$ kms$^{-1}$. From the strength of the Ca II triplet, we obtain a metallicity of [Fe/H]= $-2.48\pm0.19$ dex and dispersion of $\sigma_{\rm{[Fe/H]}}= 0.63^{+0.18}_{-0.13}$ dex. This makes Hercules a particularly metal--poor galaxy, placing it slightly below the standard mass--metallicity relation. Previous photometric and spectroscopic evidence suggests that Hercules is tidally disrupting and may be on a highly radial orbit. From our identified members, we measure no significant velocity gradient. By cross--matching with the second \textit{Gaia} data release, we determine an uncertainty--weighted mean proper motion of $\mu_{\alpha}^*=\mu_{\alpha}\cos(\delta)=-0.153\pm{0.074}$ mas yr$^{-1}$, $\mu_{\delta}=-0.397\pm0.063$ mas yr$^{-1}$. This proper motion is slightly misaligned with the elongation of Hercules, in contrast to models which suggest that any tidal debris should be well aligned with the orbital path. Future observations may resolve this tension.

[15]  arXiv:1912.00164 [pdf, ps, other]

Title: X-ray spectral shape variations in changing-look Seyfert galaxy SDSSJ155258+273728

Authors: Yanli Ai, Liming Dou, Chenwei Yang, Luming Sun, Fu-Guo Xie, Su Yao, Xue-Bing Wu, Tinggui Wang, Xinwen Shu

Comments: Submitted to ApJL

Subjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)

We analyze the X-ray, optical, and mid-infrared data of a Seyfert galaxy SDSSJ155258+273728 at $z\simeq0.086$. The broad H$\alpha$ line intensity increased by a factor of $\sim$4 in a decade. Accompanied with this, the X-ray emission detected by Chandra was about five times brighter than that from Suzaku in 2010, and the corresponding V-band, mid-infrared W1 band brighten $\sim$ 0.18, 0.32 mag, respectively. The X-ray spectrum flattens in the Chandra bright state with a photon index of $1.52^{+0.06}_{-0.06}$, compared to the value of $2.03^{+0.22}_{-0.21}$ in the Suzaku low state. Only moderate absorption was detected in all the X-ray observations with ${\rm N_{H}}\sim 10^{21} {\rm cm^{-2}}$. The accretion rate of SDSSJ155258+273728 is low with an Eddington ratio below a few percent, suggesting that the inner region of the accretion disk is possibly a hot accretion flow. By compiling the X-ray data from literatures, we find that ``changing-look" AGNs generally follow the well-studied correlation shape (``V-shape") in AGNs, that is, above a critical turn-over luminosity the X-ray spectra soften with the increasing luminosity, and below that luminosity the trend is reversed in a way of ``harder when brighter". This presents direct evidence that CL-AGNs have distinctive changes in not only the optical spectral type, but also the X-ray spectral shape. The similarity of the X-ray spectral evolution between CL-AGNs and black hole X-ray binaries in their outbursts indicates that the observed CL-AGNs phenomena may relate to the accretion state transition.

[16]  arXiv:1912.00170 [pdf, ps, other]

Title: Centrifugal acceleration of protons in the vicinity of a supermassive black hole

Authors: A. A. Gunya, Y. N. Istomin

Comments: 8 pages; Proceedings paper of "High Energy Phenomena in Relativistic Outflows VII - HEPRO VII", held 9-12 July 2019 at Facultat de F\'isica, Universitat de Barcelona, Spain; accepted by PoS

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA); High Energy Physics - Theory (hep-th)

Acceleration of protons in the active galactic nuclei is considered. The largest energy is achieved by protons during centrifugal acceleration in the magnetosphere of the central machine. When the proton accelerated in the magnetosphere of a black hole approaches light cylinder surface, acceleration occurs mainly in the azimuthal direction, i.e. the acceleration is centrifugal. In this paper the acceleration of a proton having smaller synchrotron losses compared to the electron is considered. As a proton experiences the highest energy increase while accelerating near the light surface, a partial solution for the maximum Lorentz factor can be obtained there. In the analysis the obtained dependence of the maximum energy on the parameter of particle magnetization $ \kappa $ and parameter $ \alpha $ which reflects the relation of toroidal $ B_\phi $ and poloidal $ B_T $ magnetic fields , has led to the conclusion that the achievement of theoretical maximum limit of Lorentz factor value $ \gamma_m=\kappa^{-1}$ is not possible for an accelerated particle in the magnetosphere of a black hole due to restrictions of the topology of toroidal and poloidal magnetic fields imposed. The analysis of special cases of the relation of toroidal and poloidal magnetic field has shown that in the presence of magnetic field that is significantly more toroidal the maximum Lorentz factor value reaches $\gamma_m = \kappa^ {-2/3} $, in case when toroidal field becomes smaller in comparison to poloidal field the maximum Lorentz factor value does not exceed $\gamma_m = \kappa^ {-1/2} $. For a number of objects, such as M87 and Sgr. A *, maximum Lorentz factor values for accelerated protons for scenarios of existence or lack of toroidal magnetic field have been derived. The obtained results for magnetosphere of Sgr. A * has confirmed by the experimental data obtained on the massive HESS of Cherenkov telescopes.

[17]  arXiv:1912.00179 [pdf, other]

Title: Search for Fast Radio Bursts in the Direction of the Galaxies M31 and M33

Authors: V.A.Fedorova, A.E.Rodin

Comments: 14 pages, 12 figures

Journal-ref: Astronomy Reports, 2019, Vol. 63, No. 11, pp. 877-890

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Astrophysical Phenomena (astro-ph.HE)

The results of a search for individual fast radio bursts with the Large Phased Array of the Lebedev Physical Institute at 111 MHz during July 2012 through August 2018 are presented. The signals were distinguished by convolving the data with a template with a fixed form, followed by convolution with test dispersion measures. Areas of sky containing the galaxies M31 and M33 were chosen for the search. Three radio bursts were detected in the vicinity of M33, five in the vicinity of M31, and one in a region offset from the center of M31 by an hour in right ascension. The dispersion measures of the detected bursts range from 203 to 1262 $ pc \cdot cm^{-3}$.

[18]  arXiv:1912.00190 [pdf, other]

Title: Can Non-standard Recombination Resolve the Hubble Tension?

Authors: Miaoxin Liu, Zhiqi Huang, Xiaolin Luo, Haitao Miao, Naveen K. Singh, Lu Huang

Comments: 8 pages, 3 figures;

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)

The inconsistent Hubble constant values derived from cosmic microwave background (CMB) observations and from local distance-ladder measurements may suggest new physics beyond the standard $\Lambda$CDM paradigm. It has been found in earlier works that, at least phenomenologically, non-standard recombination histories can reduce the $\gtrsim 4\sigma$ Hubble tension to $\sim 2\sigma$. Following this path, we vary physical and phenomenological parameters in RECFAST, the standard code to compute ionization history of the universe, to explore possible physics beyond standard recombination. We find that the CMB constraint on the Hubble constant is sensitive to the Hydrogen ionization energy and $2s \rightarrow 1s$ two-photon decay rate, both of which are atomic constants, and is insensitive to other details of recombination. Thus, the Hubble tension is very robust against perturbations of recombination history, unless exotic physics modifies the atomic constants during the recombination epoch.

[19]  arXiv:1912.00193 [pdf, ps, other]

Title: A magnetic confinement nuclear fusion mechanism for solar flares

Authors: Ying-Zhi Zhang

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

We propose a magnetic confinement nuclear fusion mechanism for the evolution of a solar flare in solar atmosphere. The mechanism agree with two observed characteristics of explosive flares and coronal mass ejections (CMEs) that have proved to be very difficult to explain with previous mechanisms: the huge enrichments of $^{3}He$ and the high energy gamma ray radiation. The twisted magnetic flux rope is a typical structure during the solar flares, which is closely related to the solar active region that magnetic fields have almost complete control over the plasma. Consequently, the plasma inside the flux rope is heated to more than 1.0$\times10^{7}$ K by adiabatic compression process, and then the thermonuclear fusion can take place in the flux rope accompanied with high energy gamma rays. We utilize the time-dependent ideal 2.5-dimensional magnetohydrodynamic (MHD) simulation to demonstrate the physical mechanism for producing flares, which reveals three stages of flare development with process of magnetic energy conversion and intense release during the solar flares and CMEs in solar atmosphere. Furthermore, we discuss the relationship between magnetic reconnection and solar eruptions.

[20]  arXiv:1912.00235 [pdf, ps, other]

Title: Propagation and stability of relativistic jets

Authors: Manel Perucho

Comments: Accepted for publication in the Proceedings of High Energy Phenomena in Relativistic Outflows VII - HEPRO VII. 9-12 July 2019. Proceedings of Science

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

A simple look at the steady high-energy Universe reveals a clear correlation with outflows generated around compact objects (winds and jets). In the case of relativistic jets, they are thought to be produced as a consequence of the extraction of rotational energy from a Kerr black hole (Blandford-Znajek), or from the disc (Blandford-Payne). A fraction of the large energy budget provided by accretion and/or black hole rotational energy is invested into jet formation. After formation, the acceleration and collimation of these outflows allow them to propagate to large distances away from the compact object. The synchrotron cooling times demand that re-acceleration of particles takes place along the jets to explain high-energy and very-high-energy emission from kiloparsec scales. At these scales, jets in radio galaxies are divided in two main morphological/luminosity types, namely, Fanaroff-Riley type I and II (FRI, FRII), the latter being more luminous, collimated and edge-brightened than the former, which show clear hints of decollimation and deceleration. In this contribution, I summarise a set of mechanisms that may contribute to dissipate magnetic and kinetic energy: Magnetohydrodynamic instabilities or jet-obstacle interactions trigger shocks, shearing and mixing, which are plausible scenarios for particle acceleration. I also derive an expression for the expected distance in which the entrainment by stellar winds starts to be relevant, which is applicable to FRI jets. Finally, I discuss the differences in the evolutionary scenarios and the main dissipative mechanisms that take place in extragalactic and microquasar jets.

[21]  arXiv:1912.00243 [pdf, other]

Title: The Polarization of X-rays from Warped Black Hole Accretion Disks

Authors: Quincy Abarr, Henric Krawczynski

Comments: 10 pages, accepted for publication in ApJ

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

It is commonly assumed that in black hole accretion disks the angular momenta of the disk and the black hole are aligned. However, for a significant fraction of stellar mass black holes and supermassive black holes, the momenta may not be aligned. In such systems, the interplay of disk viscosity and general relativistic frame dragging can cause the disk to warp or break into two (or more) distinct planes; this is called the Bardeen-Petterson effect. We have developed a general relativistic ray-tracing code to find the energy spectra and polarization of warped accretion disks, accounting for the emission from the disk and for photons reflecting one or multiple times off the warped accretion disk segments. We find that polarization angle can be used to give a lower limit on the misalignment angle when a previous measurement of the jet, which is thought be aligned with the black hole angular momentum, can be spatially resolved.

[22]  arXiv:1912.00250 [pdf, ps, other]

Title: Linear Stability in the Inner Heliosphere: Helios Reëvaluated

Authors: Kristopher G. Klein, Mihailo Martinovic, David Stansby, Timothy S. Horbury

Comments: 10 Pages, 6 Figures, Accepted in ApJ

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Plasma Physics (physics.plasm-ph); Space Physics (physics.space-ph)

Wave-particle instabilities driven by departures from local thermodynamic equilibrium have been conjectured to play a role in governing solar wind dynamics. We calculate the statistical variation of linear stability over a large subset of Helios I and II fast solar wind observations using a numerical evaluation of the Nyquist stability criterion, accounting for multiple sources of free energy associated with protons and helium including temperature anisotropies and relative drifts. We find that 88\% of the surveyed intervals are linearly unstable. The median growth rate of the unstable modes is within an order of magnitude of the turbulent transfer rate, fast enough to potentially impact the turbulent scale-to-scale energy transfer. This rate does not significantly change with radial distance, though the nature of the unstable modes, and which ion components are responsible for driving the instabilities, does vary. The effect of ion-ion collisions on stability is found to be significant; collisionally young wind is much more unstable than collsionally old wind, with very different kinds of instabilities present in the two kinds of wind.

[23]  arXiv:1912.00255 [pdf, other]

Title: Do Metal-Rich Stars Make Metal-Rich Planets? New Insights on Giant Planet Formation from Host Star Abundances

Authors: Johanna K. Teske, Daniel Thorngren, Jonathan J. Fortney, Natalie Hinkel, John M. Brewer

Comments: Main results in Figure 3-5. Published in AJ on 2019-11-20. 24 pages (single column style)

Journal-ref: The Astronomical Journal, Volume 158, Issue 6, article id. 239, 18 pp. (2019) Link: https://iopscience.iop.org/article/10.3847/1538-3881/ab4f79

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)

The relationship between the compositions of giant planets and their host stars is of fundamental interest in understanding planet formation. The solar system giant planets are enhanced above solar composition in metals, both in their visible atmospheres and bulk compositions. A key question is whether the metal enrichment of giant exoplanets is correlated with that of their host stars. Thorngren et al. (2016) showed that in cool (Teq < 1000 K) giant exoplanets, the total heavy-element mass increases with total Mp and the heavy element enrichment relative to the parent star decreases with total Mp. In their work, the host star metallicity was derived from literature [Fe/H] measurements. Here we conduct a more detailed and uniform study to determine whether different host star metals (C, O, Mg, Si, Fe, and Ni) correlate with the bulk metallicity of their planets, using correlation tests and Bayesian linear fits. We present new host star abundances of 19 cool giant planet systems, and combine these with existing host star data for a total of 22 cool giant planet systems (24 planets). Surprisingly, we find no clear correlation between stellar metallicity and planetary residual metallicity (the relative amount of metal versus that expected from the planet mass alone), which is in conflict with common predictions from formation models. We also find a potential correlation between residual planet metals and stellar volatile-to-refractory element ratios. These results provide intriguing new relationships between giant planet and host star compositions for future modeling studies of planet formation.

[24]  arXiv:1912.00274 [pdf, other]

Title: Fast Neutrino Flavor Instability in the Neutron-star Convection Layer of Three-dimensional Supernova Models

Authors: Robert Glas (1,2), H.-Thomas Janka (1), Francesco Capozzi (3), Manibrata Sen (4,5), Basudeb Dasgupta (6), Alessandro Mirizzi (7,8), Guenter Sigl (9) ((1) MPI Astrophysics, Garching, (2) TUM, Munich, (3) MPI Physik, Munich, (4) UC Berkeley, Berkeley, (5) Northwestern University, Evanston, (6) Tata Institute of Fundamental Research, Mumbai, (7) Dipartimento Interateneo di Fisica, Bari, (8) Istituto Nazionale di Fisica Nucleare, Bari, (9) Inst. Theor. Physik, Hamburg University)

Comments: 20 pages, 13 figures

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)

Neutrinos from a supernova (SN) might undergo fast flavor conversions near the collapsed stellar core. We perform a detailed study of this intriguing possibility, analyzing time-dependent state-of-the-art 3D SN models of 9 and 20 Msun. Both models were computed with multi-D three-flavor neutrino transport based on a two-moment solver, and both exhibit the presence of the lepton-number emission self-sustained asymmetry (LESA). The transport solution does not provide the angular distributions of the neutrino fluxes, which are crucial to track the fast flavor instability. To overcome this limitation, we use a recently proposed approach based on the angular moments of the energy-integrated electron lepton-number distribution. With this method we find the possibility of fast neutrino flavor instability at radii <~20 km, which is well interior to the neutrinosphere. Our results confirm recent observations in a 2D SN model and in 2D/3D models with fixed matter background, which were computed with Boltzmann neutrino transport. However, the flavor unstable locations are not isolated points as discussed previously, but thin skins surrounding volumes where electron antineutrinos are more abundant than electron neutrinos. These volumes grow with time and appear first in the convective layer of the proto-neutron star (PNS), where a decreasing electron fraction (Ye) and high temperatures favor the occurrence of regions with negative neutrino chemical potential. Since Ye remains higher in the LESA dipole direction, where convective lepton-number transport out from the nonconvective PNS core slows down the deleptonization, flavor unstable conditions become more widespread in the opposite hemisphere. This interesting phenomenon deserves further investigation, since its impact on SN modeling and possible consequences for SN dynamics and neutrino observations are presently unclear. (abridged)

[25]  arXiv:1912.00278 [pdf, other]

Title: R-L Relation in Realistic FRADO Model

Authors: Mohammad-Hassan Naddaf, Bozena Czerny, Ryszard Szczerba

Comments: 3 pages, 1 figure, 39th Congress of the Polish Astronomical Society, September 2019, Olsztyn, Poland

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)

In Failed Radiatively Accelerated Dusty Outflow (FRADO) model which provides the source of material above the accretion disk (AD) as an option to explain the formation mechanism of Broad Line Region (BLR) in AGNs, the BLR inner radius ($\rm{BLR}_{in}$ hereafter) is set by the condition that the dust evaporates immediately upon departure from the AD surface. On the other hand, the location of BLR clouds obtained observationaly via reverberation mapping shows some scaling with the source luminosity, so-called RL relation. We assume $\rm{BLR}_{in}$ to be the location of BLR clouds, then using a realistic expression for the radiation pressure of an AD, and having included the proper values of dust opacity, and shielding effect as well, we report our numerical results on calculation of $\rm{BLR}_{in}$ based on FRADO model. We investigate how it scales with monochromatic luminosity at 5100 angstrom for a grid of blackhole masses and Eddington ratios to compare along with the FRADO analytically predicted RL directly to observational data.

[26]  arXiv:1912.00291 [pdf, other]

Title: A sub-Neptune sized planet transiting the M2.5-dwarf G 9-40: Validation with the Habitable-zone Planet Finder

Authors: Gudmundur Stefansson, Caleb Cañas, John Wisniewski, Paul Robertson, Suvrath Mahadevan, Marissa Maney, Shubham Kanodia, Corey Beard, Chad F. Bender, Peter Brunt, J. Christopher Clemens, William Cochran, Scott A. Diddams, Michael Endl, Eric B. Ford, Connor Fredrick, Samuel Halverson, Fred Hearty, Leslie Hebb, Joseph Huehnerhoff, Jeff Jennings, Kyle Kaplan, Eric Levi, Emily Lubar, Andrew J. Metcalf, Andrew Monson, Brett Morris, Joe P. Ninan, Colin Nitroy, Lawrence Ramsey, Arpita Roy, Christian Schwab, Steinn Sigurdsson, Ryan Terrien, Jason T. Wright

Comments: Accepted for publication in AJ, 22 pages, 15 figures

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)

We validate the discovery of a 2 Earth radii sub-Neptune-size planet around the nearby high proper motion M2.5-dwarf G 9-40 (EPIC 212048748), using high-precision near-infrared (NIR) radial velocity (RV) observations with the Habitable-zone Planet Finder (HPF), precision diffuser-assisted ground-based photometry with a custom narrow-band photometric filter, and adaptive optics imaging. At a distance of $d=27.9\mathrm{pc}$, G 9-40b is the second closest transiting planet discovered by K2 to date. The planet's large transit depth ($\sim$3500ppm), combined with the proximity and brightness of the host star at NIR wavelengths (J=10, K=9.2) makes G 9-40b one of the most favorable sub-Neptune-sized planet orbiting an M-dwarf for transmission spectroscopy with JWST, ARIEL, and the upcoming Extremely Large Telescopes. The star is relatively inactive with a rotation period of $\sim$29 days determined from the K2 photometry. To estimate spectroscopic stellar parameters, we describe our implementation of an empirical spectral matching algorithm using the high-resolution NIR HPF spectra. Using this algorithm, we obtain an effective temperature of $T_{\mathrm{eff}}=3404\pm73$K, and metallicity of $\mathrm{[Fe/H]}=-0.08\pm0.13$. Our RVs, when coupled with the orbital parameters derived from the transit photometry, exclude planet masses above $11.7 M_\oplus$ with 99.7% confidence assuming a circular orbit. From its radius, we predict a mass of $M=5.0^{+3.8}_{-1.9} M_\oplus$ and an RV semi-amplitude of $K=4.1^{+3.1}_{-1.6}\mathrm{m\:s^{-1}}$, making its mass measurable with current RV facilities. We urge further RV follow-up observations to precisely measure its mass, to enable precise transmission spectroscopic measurements in the future.

[27]  arXiv:1912.00335 [pdf, other]

Title: Three-dimensional dissipative pulsar magnetospheres with Aristotelian electrodynamics

Authors: Gang Cao, Xiongbang Yang

Comments: Accepted by ApJ

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

A good compromise between the resistive model and the PIC model is Aristotelian electrodynamics, which can include the back-reaction of the radiative photons onto particle motion and allow for a local dissipation where the force-free condition is violate. We study the dissipative pulsar magnetosphere with Aristotelian electrodynamics where particle acceleration is fully balanced by radiation. The expression for the current sheet is defined by introducing a pair multiplicity. The 3D structure of pulsar magnetosphere is then presented by solving the time-dependent Maxwell equations using a pseudo-spectral algorithm. It is found that the dissipative magnetosphere approaches the force-free solution and the dissipative region is more restricted to the current sheet outside the light-cylinder (LC) as the pair multiplicity increases. The spatial extension of the dissipative region is self-consistently controlled by the pair multiplicity. Our simulations show the high magnetospheric dissipation outside the LC for the low pair multiplicity.

[28]  arXiv:1912.00371 [pdf, other]

Title: Enhancement of impact heating in pressure-strengthened rocks in oblique impacts

Authors: Shigeru Wakita, Hidenori Genda, Kosuke Kurosawa, Thomas M Davison

Comments: 14 pages, 5 figures, accepted for publication in Geophysical Research Letters

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

Shock-induced metamorphism in meteorites informs us about the collisional environment and history of our solar system. Recently the importance of material strength in impact heating was reported from head-on impact simulations. Here, we perform three-dimensional oblique impact simulations, and confirm the additional heating due to material strength for oblique impacts. Despite a large difference in the peak pressure at the impact point at a given impact velocity, we find that the heated mass for an oblique impact is nearly the same as that for a head-on impact. Thus, our results differ from the previous finding that the heated mass decreases as the impact becomes more oblique, and show that the additional shear heating is more effective for oblique impacts than for head-on impacts. This also indicates that material ejected during oblique impact tends to experience lower shock pressures but higher temperatures.

[29]  arXiv:1912.00375 [pdf, other]

Title: Physical Implications of the Sub-threshold GRB GBM-190816 and its Associated Sub-threshold Gravitational Wave Event

Authors: Yi-Si Yang, Shu-Qing Zhong, Bin-Bin Zhang, Shichao Wu, Bing Zhang, Yu-Han Yang, Zhoujian Cao, He Gao, Jin-Hang Zou, Jie-Shuang Wang, Hou-Jun Lü, Ji-Rong Cang, Zi-Gao Dai

Comments: 22 pages, 11 figures. Submitted to ApJL

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

LIGO-Virgo and Fermi collaborations recently reported a possible joint detection of a sub-threshold GW event and a sub-threshold GRB, GBM-190816, that occurred 1.57 s after the merger. Since it takes long for the official LIGO-Virgo/Fermi Collaboration's results to be released, we decide to independently process the publicly available data and investigate the physical implications of this potential association. We perform a detailed analysis of the observational properties of the GBM-190816. By studying its signal-to-noise ratio, duration, f-parameter, spectral properties, energetic properties, and its compliance with some GRB statistical correlations, we confirm that this event is likely a typical short GRB with a luminosity of $1.02_{-0.80}^{+2.84} \times 10^{49} erg s^{-1}$. Based on the available information, we infer the mass ratio, $q$, of the binary compact stars in the range of $\sim$ [2.142, 5.795]. The leading physical scenario invokes an NS-BH merger system with the NS tidally disrupted. We derive the physical properties of such a system that are required to produce a GRB. The GW data in principle allow NS-BH systems with no tidal disruptio or BH-BH mergers. The generation of a GRB in these systems requires that at least one of the merger member is charged. We apply the charged compact binary coalescence (cCBC) theory to derive the model parameters to account for GBM-190816. The cases for both constant and increasing charges in the merging members are discussed. Finally, since in NS-BH or BH-BH merger systems a BH exists immediately after the merger so that there is no waiting time before launching a jet, the fact that the observed delay time scale is comparable to that of the NS-NS merger event GW170817/GRB 170817A suggests that the commonly observed GW-GRB time delay is mainly defined by the time scale for the jet propagates to the energy dissipation / GRB emission site.

[30]  arXiv:1912.00387 [pdf, other]

Title: Mutual Orbital Inclinations Between Cold Jupiters and Inner Super-Earths

Authors: Kento Masuda, Joshua N. Winn, Hajime Kawahara

Comments: accepted for publication in The Astronomical Journal, 22 pages, 4 figures

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

Previous analyses of Doppler and Kepler data have found that Sun-like stars hosting "cold Jupiters" (giant planets with $a\gtrsim 1\,\mathrm{AU}$) almost always host "inner super-Earths" (1-$4\,R_\oplus$, $a\lesssim1\,\mathrm{AU}$). Here, we attempt to determine the degree of alignment between the orbital planes of the cold Jupiters and the inner super-Earths. The key observational input is the fraction of Kepler stars with transiting super-Earths that also have transiting cold Jupiters. This fraction depends on both the probability for cold Jupiters to occur in such systems, and on the mutual orbital inclinations. Since the probability of occurrence has already been measured in Doppler surveys, we can use the data to constrain the dispersion of the mutual inclination distribution. We find $\sigma=11.8^{+12.7}_{-5.5}\,\mathrm{deg}$ (68% confidence) and $\sigma>3.5\,\mathrm{deg}$ (95% confidence), where $\sigma$ is the scale parameter of the Rayleigh distribution. This suggests that planetary orbits in systems with cold Jupiters tend to be coplanar - although not quite as coplanar as those in the Solar System, which have a mean inclination from the invariable plane of $1.8\,\mathrm{deg}$. We also find evidence that cold Jupiters have lower mutual inclinations relative to inner systems with higher transit multiplicity. This suggests a link between the dynamical excitation in the inner and outer systems. For example, perturbations from misaligned cold Jupiters may dynamically heat or destabilize systems of inner super-Earths.

[31]  arXiv:1912.00388 [pdf, ps, other]

Title: Nonaxisymmetric Component of Solar Activity and the Gnevyshev-Ohl Rule

Authors: Elena Vernova, Marta Tyasto, Dmitrii Baranov, Olga Danilova

Comments: 15 pages, 9 figures

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

The vector representation of sunspots is used to study the nonaxisymmetric features of the solar activity distribution (sunspot data from Greenwich - USAF/NOAA, 1874 - 2016).The vector of the longitudinal asymmetry is defined for each Carrington rotation; its modulus characterizes the magnitude of the asymmetry, while its phase points to the active longitude. These characteristics are to a large extent free from the influence of a stochastic component and emphasize the deviations from the axisymmetry. For the sunspot area, the modulus of the vector of the longitudinal asymmetry changes with the 11-year period; however, in contrast to the solar activity, the amplitudes of the asymmetry cycles obey a special scheme. Each pair of cycles from 12 to 23 follows in turn the Gnevyshev - Ohl rule (an even solar cycle is lower than the following odd cycle) or the anti-Gnevyshev - Ohl rule (an odd solar cycle is lower than the preceding even cycle). This effect is observed in the longitudinal asymmetry of the whole disk and the southern hemisphere. Possibly, this effect is a manifestation of the 44-year structure in the activity of the Sun. Northern hemisphere follows the Gnevyshev - Ohl rule in Solar Cycles 12 - 17, while in Cycles 18 - 23 the anti-rule is observed.

[32]  arXiv:1912.00399 [pdf, other]

Title: Constraining the long-lived magnetar remnants in short gamma-ray bursts from late-time radio observations

Authors: Liang-Duan Liu, He Gao, Bing Zhang

Comments: 23 pages, 6 figures, 3 tables

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

The joint detection of GW 170817 and GRB 170817A indicated that at least a fraction of short gamma ray bursts (SGRBs) originate from binary neutron star (BNS) mergers. One possible remnant of a BNS merger is a rapidly rotating, strongly magnetized neutron star, which has been discussed as one possible central engine for GRBs. For a rapidly rotating magnetar central engine, the deposition of the rotation energy into the ejecta launched from the merger could lead to bright radio emission. The brightness of radio emission years after an SGRB would provide an estimation of the kinetic energy of ejecta and hence, a possible constraint on the BNS merger product. We perform a more detailed calculation on the brightness of radio emission from the interaction between the merger ejecta and circumburst medium in the magnetar scenario, invoking several important physical processes such as generic hydrodynamics, relativistic effects, and the deep Newtonian phase. We use the model to constrain the allowed parameter space for 15 SGRBs that have late radio observations. Our results show that an injected energy $E_{\rm inj} \sim 10^{52}$ erg is allowed for all the cases, which suggests that the possibility of a supra-massive or hyper-massive neutron star remnant is not disfavored by the available radio data.

[33]  arXiv:1912.00405 [pdf, other]

Title: Complex asteroseismology of SX Phoenicis

Authors: J. Daszyńska-Daszkiewicz, P. Walczak, A. Pamyatnykh, W. Szewczuk, W. Dziembowski

Comments: 5 pages, 2 figures, Proceedings of the Vienna Conference "Stars and their Variability, )bserved from Space"

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

We present seismic analysis of the prototype SX Phoenicis that aims at fitting the two radial-mode frequencies and the corresponding values of the bolometric flux amplitude (the parameter $f$), whose empirical values are derived from multi-coulor photometric observations. Seismic model that meets these conditions is of low mass, $M=1.05 M_\odot$, has moderately effective convection in the outer layers, described by the mixing length parameter $\alpha_{\rm MLT} \approx 0.7$, and the microturbulent velocity in the atmospheres of about $\xi_{\rm t}\approx 8$km/s. Such seismic studies of stars like SX Phe are very important for deriving constraints on outer-layer convection, because the object is on the border between very effective and ineffective convection.

[34]  arXiv:1912.00409 [pdf, ps, other]

Title: Testing stellar opacities using asteroseismology

Authors: Jadwiga Daszynska-Daszkiewicz, Przemyslaw Walczak, Alosha Pamyatnykh, Wojciech Szewczuk

Comments: 6 pages, 2 figures, 1 table, Proceedings of XXXVIII Polish Astronomical Society Meeting

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

We present what constraints on opacities can be derived from the analysis of stellar pulsations of BA-type main-sequence stars. This analysis consists of the construction of complex seismic models which reproduce the observed frequencies as well as the bolometric flux amplitude extracted from the multi-colour photometric variations. Stellar seismology, i.e., {\it asteroseismology}, is a relatively young branch of astrophysics and, currently, provides the most accurate test of the theory of internal structure and evolution. We show that opacities under stellar conditions need to be modified at the depth of temperatures $T=110~000-290~000$\,K. The revision of opacity data is of great importance because they are crucial for all branches of astrophysics.

[35]  arXiv:1912.00432 [pdf, other]

Title: Modelling cosmic ray electron physics in cosmological smoothed particle hydrodynamics simulation

Authors: Dongchao Zheng, Weitian Li, Zhenghao Zhu, Chenxi Shan, Jiajun Zhang, Linfeng Xiao, Xiaoli Lian, Dan Hu

Comments: 13 pages, 11 figures

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

Cosmic ray electron (CRE) acceleration and cooling are important physical processes in astrophysics. We develop an approximative framework to treat CRE physics in the parallel smoothed particle hydrodynamics code Gadget-3. In our methodology, the CRE spectrum of each fluid element is approximated by a single power-law distribution with spatially varying amplitude, upper cut-off, lower cut-off, and spectral index. We consider diffusive shock acceleration to be the source of injection, and oppositely the sinking processes is attributed to synchrotron radiation, inverse Compton scatters, and Coulomb scatters. The adiabatic gains and losses are also included. We show that our formalism produces the energy and pressure with an accuracy of $ > 90\%$ for a free cooling CRE spectrum. Both slope and intensity of the radio emission computed from the CRE population given by our method in cosmological hydro-simulation coincide well with observations, and our results also show that relaxed clusters have lower fluxes. Finally, we investigate several impacts of the CRE processes on the cosmological hydro-simulation, we find that: (1) the pressure of the CRE spectrum is very small and can be ignored in hydro-simulation, (2) the impacts of the CRE processes on the gas phase-space state of hydro-simulation is up to $3\%$, (3) the CRE processes induce a $5\%$ influence on the mass function in the mass range $10^{12} -10^{13} h^{-1} M_{\odot}$, (4) The gas temperature of massive galaxy cluster is influenced by the CRE processes up to $\sim 10\%$.

[36]  arXiv:1912.00441 [pdf, ps, other]

Title: Cluster formation induced by a cloud--cloud collision in [DBS2003]179

Authors: Sho Kuwahara, Kazufumi Torii, Norikazu Mizuno, Shinji Fujita, Mikito Kohno, Yasuo Fukui

Comments: 32 pages, 16 figures

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[DBS2003]179 is a super star cluster in the Galaxy discovered by deep near infrared observations. We carried out CO J=1-0 and J=3-2 observations of the region of [DBS2003]179 with NANTEN2, ASTE and the Mopra 22m telescope. We identified and mapped two molecular clouds which are likely associated with the cluster. The association is evidenced by the spatial correlation with the 8 micron Spitzer image, and a high ratio of the two transitions of 12CO (J=3-2 to J=1-0). The two clouds show complementary distribution in space and bridge features connecting them in velocity. We frame a hypothesis that the two clouds collided with each other 1-2 Myr ago, and the collision compressed the interface layer, triggering the formation of the cluster. This offers an additional piece of evidence for a super star cluster formed by cloud--cloud collision alongside of the four super star clusters including Wd2, NGC3603, RCW38 and R136. The findings indicate that the known super star clusters having closely associated dust emission are formed by cloud-cloud collision, lending support for the important role of cloud--cloud collision in high-mass star formation.

[37]  arXiv:1912.00482 [pdf, other]

Title: The NANOGrav 11-year Data Set: Constraints on Planetary Masses Around 45 Millisecond Pulsars

Authors: E. A. Behrens, S. M. Ransom, D. R. Madison, Z. Arzoumanian, K. Crowter, M. E. DeCesar, P. B. Demorest, T. Dolch, J. A. Ellis, R. D. Ferdman, E. C. Ferrara, E. Fonseca, P. A. Gentile, G. Jones, M. L. Jones, M. T. Lam, L. Levin, D. R. Lorimer, R. S. Lynch, M. A. McLaughlin, C. Ng, D. J. Nice, T. T. Pennucci, B. B. P. Perera, P. S. Ray, R. Spiewak, I. H. Stairs, K. Stovall, J. K. Swiggum, W. W. Zhu

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)

We search for extrasolar planets around millisecond pulsars using pulsar timing data and seek to determine the minimum detectable planetary masses as a function of orbital period. Using the 11-year data release from the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), we look for variations from our models of pulse arrival times due to the presence of exoplanets. No planets are detected around the millisecond pulsars in the NANOGrav 11-year data set, but taking into consideration the noise levels specific to each pulsar as well as the sampling rate of our observations, we develop limits that show we are sensitive to planetary masses as low as those of the moon and even large asteroids.

[38]  arXiv:1912.00494 [pdf, other]

Title: On the importance of special relativistic effects in modelling ultra-fast outflows

Authors: A. Luminari, F. Tombesi, E. Piconcelli, F. Nicastro, K. Fukumura, D. Kazanas, F. Fiore, L. Zappacosta

Comments: 6 pages, 5 figures. Accepted for publication in A&A

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

Outflows are observed in a variety of astrophysical sources. Remarkably, ultra-fast ($v\geq 0.1c$), outflows in the UV and X-ray bands are often seen in AGNs. Depending on their energy and mass outflow rate, respectively $\dot{E}_{out}, \dot{M}_{out}$, such outflows may play a key role in regulating the AGN-host galaxy co-evolution process through cosmic time. It is therefore crucial to provide accurate estimates of the wind properties. Here, we concentrate on special relativistic effects concerning the interaction of light with matter moving at relativistic speed relatively to the source of radiation. Our aim is to assess the impact of these effects on the observed properties of the outflows and implement a relativistic correction in the existing spectral modelling routines. We define a simple procedure to incorporate relativistic effects in radiative transfer codes. Following this procedure, we run a series of simulations to explore the impact of these effects on the simulated spectra, for different $v$ and column densities of the outflow. The observed optical depth is usually considered a proxy for the wind $N_H$, independently on its velocity. However, our simulations show that the observed optical depth of an outflow with a given column density $N_H$ decreases rapidly as the velocity of the wind approaches relativistic values. This, in turn, implies that when estimating $N_H$ from the optical depth, it is necessary to include a velocity-dependent correction, already for moderate velocities (e.g. $v \geq 0.05c$). This correction linearly propagates to the derived $\dot{M}_{out}, \dot{E}_{out}$. As an example of these effects, we calculate the relativistically corrected values of $\dot{M}_{out}$ and $\dot{E}_{out}$ for a sample of $\sim 30$ Ultra-Fast Outflows taken from the literature, and find correction factors of $20-120 \%$ within the observed range of outflowing velocities.

[39]  arXiv:1912.00502 [pdf, other]

Title: Predicting solar flares with machine learning: investigating solar cycle dependence

Authors: Xiantong Wang, Yang Chen, Gabor Toth, Ward B. Manchester, Tamas I. Gombosi, Alfred O. Hero, Zhenbang Jiao, Hu Sun, Meng Jin, Yang Liu

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

A deep learning network, Long-Short Term Memory (LSTM) network, is used in this work to predict whether the maximum flare class an active region (AR) will produce in the next 24 hours is class $\Gamma$. We considered $\Gamma$ are $\ge M$, $\ge C$ and any flare class. The essence of using LSTM, which is a recurrent neural network, is its capability to capture temporal information of the data samples. The input features are time sequences of 20 magnetic parameters from SHARPs - Space-weather HMI Active Region Patches. We analyzed active regions from June 2010 to Dec 2018, using the Geostationary Operational Environmental Satellite (GOES) X-ray flare catalogs and label the data samples with identified ARs in the GOES X-ray flare catalogs. Our results (i) shows consistent skill scores with recently published results using LSTMs and better than the previous work using single time input (eg. DeFN) (ii) The skill scores from the model show essential differences when different years of data was chosen for training and testing.

[40]  arXiv:1912.00526 [pdf, ps, other]

Title: Fast Radio Bursts Not Made By Neutron Stars

Authors: J. I. Katz

Comments: 3 pp

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

Popular models of repeating Fast Radio Bursts (and perhaps of all Fast Radio Bursts) involve neutron stars because they may have high rotational or magnetostatic energy densities available to power energetic bursts. These models take two forms: giant but rare pulsar-like pulses like those of Rotating RAdio Transients and outbursts like those of Soft Gamma Repeaters. Here I collate the evidence, recently strengthened, against these models.

[41]  arXiv:1912.00560 [pdf, ps, other]

Title: Testing the relativistic Doppler boost hypothesis for supermassive binary black holes candidates via broad emission line profiles

Authors: Zihao Song, Junqiang Ge, Youjun Lu, Xiang Ji

Comments: Accepted for publication in MNRAS, 9 pages, 7 figures

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Optical periodicity QSOs found by transient surveys are suggested to be sub-parsec supermassive binary black holes (BBHs). An intriguing interpretation for the periodicity of some of those QSOs is that the continuum is radiated from the accretion disk associated with the BBH secondary component and modulated by the periodical rotation of the secondary via Doppler-boost effect. Close to edge-on orbital orientation can lead to more significant Doppler-boost effect and thus are preferred for these systems, which is distinct from those normal type-1 QSOs with more or less face-on orientations. Therefore, the profiles of broad lines emitted from these Doppler-modulated systems may be significantly different from other systems that are not Doppler-modulated. We investigate the properties of the broad emission lines of optical-periodicity QSOs, including both a sample of QSOs that can be interpreted by the Doppler-modulated effects and a sample that cannot. We find that there is no obvious difference in the profiles and other properties of various (stacked) broad emission lines of these two samples, though a simple broad line region model would suggest significant differences. Our finding raises a challenge to the Doppler boost hypothesis for some of those BBHs candidates with optical periodicity.

[42]  arXiv:1912.00588 [pdf, other]

Title: Pilot HI Survey of Planck Galactic Cold Clumps with FAST

Authors: Ningyu Tang, Di Li, Pei Zuo, Lei Qian, Tie Liu, Yuefang Wu, Marko Krčo, Mengting Liu, Youling Yue, Yan Zhu, Hongfei Liu, Dongjun Yu, Jinghai Sun, Peng Jiang, Gaofeng Pan, Hui Li, Hengqian Gan, Rui Yao, Shu Liu, FAST Collaboration

Comments: 11 pages, 11 figures, accepted by the Research in Astronomy and Astrophysics (RAA)

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We present a pilot HI survey of 17 Planck Galactic Cold Clumps (PGCCs) with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). HI Narrow Self-Absorption (HINSA) is an effective method to detect cold HI being mixed with molecular hydrogen H$_2$ and improves our understanding of the atomic to molecular transition in the interstellar medium. HINSA was found in 58\% PGCCs that we observed. The column density of HINSA was found to have an intermediate correlation with that of $^{13}$CO, following $\rm log( N(HINSA)) = (0.52\pm 0.26) log(N_{^{13}CO}) + (10 \pm 4.1) $. HI abundance relative to total hydrogen [HI]/[H] has an average value of $4.4\times 10^{-3}$, which is about 2.8 times of the average value of previous HINSA surveys toward molecular clouds. For clouds with total column density N$\rm_H >5 \times 10^{20}$ cm$^{-2}$, an inverse correlation between HINSA abundance and total hydrogen column density is found, confirming the depletion of cold HI gas during molecular gas formation in more massive clouds. Nonthermal line width of $^{13}$CO is about 0-0.5 km s$^{-1}$ larger than that of HINSA. One possible explanation of narrower nonthermal width of HINSA is that HINSA region is smaller than that of $^{13}$CO. Based on an analytic model of H$_2$ formation and H$_2$ dissociation by cosmic ray, we found the cloud ages to be within 10$^{6.7}$-10$^{7.0}$ yr for five sources.

[43]  arXiv:1912.00625 [pdf, other]

Title: Identifying nearby sources of ultra-high-energy cosmic rays with deep learning

Authors: Oleg Kalashev, Maxim Pshirkov, Mikhail Zotov

Comments: 12 pages, 3 figures

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

We present a method to analyse arrival directions of ultra-high-energy cosmic rays (UHECRs) using a classifier defined by a deep convolutional neural network trained on a HEALPix grid. To illustrate the efficacy of the method, we employ it to estimate prospects of detecting a large-scale anisotropy of UHECRs induced by a nearby source with an (orbital) detector having a uniform exposure of the celestial sphere and compare the results with our earlier calculations based on the angular power spectrum. A minimal model for extragalactic cosmic rays and neutrinos by Kachelrie{\ss}, Kalashev, Ostapchenko and Semikoz (2017) is assumed for definiteness and nearby active galactic nuclei Centaurus A, M82, NGC253, M87 and Fornax A are considered as possible sources of UHECRs. We demonstrate that the proposed method drastically improves sensitivity of an experiment by decreasing the minimal required amount of detected UHECRs or the minimal detectable fraction of from-source events several times compared to the approach based on the angular power spectrum. The method can be readily applied to the analysis of data of the Telescope Array, the Pierre Auger Observatory and other cosmic ray experiments.

[44]  arXiv:1912.00655 [pdf, other]

Title: Probing the azimuthal environment of galaxies around clusters. From cluster core to cosmic filaments

Authors: C. Gouin, N. Aghanim, V. Bonjean, M. Douspis

Comments: Submitted to A&A, 13 pages, comments welcome

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

Galaxy clusters are connected at their peripheries to the large scale structures by cosmic filaments that funnel accreting material. These filamentary structures are studied to investigate both environment-driven galaxy evolution and structure formation and evolution. In the present work, we probe in a statistical manner the azimuthal distribution of galaxies around clusters as a function of the cluster-centric distance, the cluster richness, and the galaxy activity (star-forming or passive).We perform a harmonic decomposition in large photometric galaxy catalogue around 6400 SDSS clusters with masses M >1e14 solar masses, in the redshift range of 0.1< z <0.3. The same analysis is performed on the mock galaxy catalogue from the light-cone of Magneticum hydrodynamical simulation.
We use the multipole analysis to quantify asymmetries in the 2-D galaxy distribution. In the inner cluster regions at R <2 R500, we confirm that the galaxy distribution traces an ellipsoidal shape, which is more pronounced for richest clusters. In the clusters' outskirts (R= [2-8]R500), filamentary patterns are detected in harmonic space with a mean angular scale m_mean= 4.2+/-0.1. Massive clusters seem to have a larger number of connected filaments than low massive ones. We also find that passive galaxies appear to better trace the filamentary structures around clusters, even if the contribution of SF ones tend to increase with the cluster-centric distance, suggesting a gradient of galaxy activity in filaments around clusters.

[45]  arXiv:1912.00668 [pdf, ps, other]

Title: Model-independent Distance Calibration and Curvature Measurement using Quasars and Cosmic Chronometers

Authors: Jun-Jie Wei, Fulvio Melia

Comments: 8 pages, 5 figures, 2 tables. Accepted for publication in ApJ

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

We present a new model-independent method to determine the spatial curvature and to mitigate the circularity problem affecting the use of quasars as distance indicators. The cosmic-chronometer measurements are used to construct the curvature-dependent luminosity distance $D^{\rm cal}_{L}(\Omega_{K},z)$ using a polynomial fit. Based on the reconstructed $D^{\rm cal}_{L}(\Omega_{K},z)$ and the known ultraviolet versus X-ray luminosity correlation of quasars, we simultaneously place limits on the curvature parameter $\Omega_{K}$ and the parameters characterizing the luminosity correlation function. This model-independent analysis suggests that a mildly closed Universe ($\Omega_{K}=-0.918\pm0.429$) is preferred at the $2.1\sigma$ level. With the calibrated luminosity correlation, we build a new data set consisting of 1598 quasar distance moduli, and use these calibrated measurements to test and compare the standard $\Lambda$CDM model and the $R_{\rm h}=ct$ universe. Both models account for the data very well, though the optimized flat $\Lambda$CDM model has one more free parameter than $R_{\rm h}=ct$, and is penalized more heavily by the Bayes Information Criterion. We find that $R_{\rm h}=ct$ is slightly favoured over $\Lambda$CDM with a likelihood of $\sim57.7\%$ versus 42.3\%.

[46]  arXiv:1912.00705 [pdf, other]

Title: R-mode oscillations in eclipsing binaries

Authors: Hideyuki Saio

Comments: 4 pages, submitted for conference proceedings "Starts and their variability - observed from space" held in Vienna in August, 2019, Eds. C. Neiner et al

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

The presence of r mode oscillations (global modes of Rossby waves coupled with buoyancy) in an eclipsing binary is recognized as frequency groups in a frequency-amplitude diagram obtained from a Fourier analysis of Kepler light curve data. The frequency at the upper bound of an r-mode frequency group is close to the rotation frequency of the star. Analysing about eight hundred Kepler light curves of eclipsing binaries finds about seven hundred cases showing the signature of r modes. Sometimes two sets of the frequency groups are found, which indicates the two component stars to have slightly different rotation frequencies. Plotting thus obtained rotation frequencies with respect to orbital frequencies, we find that rotation is roughly synchronous to the orbital frequency if the latter is larger than about 1 c/d, while some stars rotate super-synchronously in systems with longer orbital periods.

[47]  arXiv:1912.00707 [pdf]

Title: The Dawn of Dust Astronomy

Authors: Eberhard Grün, Harald Krüger, Ralf Srama

Comments: 97 pages, 19 figures, 2 Tables, to be published in ISSI book Cosmic Dust from the Laboratory to the Stars, Edited by Rafael Rodrigo, J\"urgen Blum, Hsiang-Wen Hsu, Detlef Koschny, Anny-Chantal Levasseur-Regourd, Jesus Martin-Pintado, Veerle Sterken and Andrew Westphal

Journal-ref: Space Science Reviews (2019) 215:46

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

We review the development of dust science from the first ground-based astronomical observations of dust in space to compositional analysis of individual dust particles and their source objects. A multitude of observational techniques is available for the scientific study of space dust: from meteors and interplanetary dust particles collected in the upper atmosphere to dust analyzed in situ or returned to Earth. In situ dust detectors have been developed from simple dust impact detectors determining the dust hazard in Earth orbit to dust telescopes capable of providing compositional analysis and accurate trajectory determination of individual dust particles in space. The concept of Dust Astronomy has been developed, recognizing that dust particles, like photons, carry information from remote sites in space and time. From knowledge of the dust particles' birthplace and their bulk properties, we learn about the remote environment out of which the particles were formed. Dust Observatory missions like Cassini, Stardust, and Rosetta study Saturn's satellites and rings and the dust environments of comet Wild 2 and comet Churyumov-Gerasimenko, respectively. Supplemented by simulations of dusty processes in the laboratory we are beginning to understand the dusty environments in space.

[48]  arXiv:1912.00709 [pdf]

Title: Phasing a deployable sparse telescope

Authors: Erez N. Ribak, B. Martin Levine

Comments: 5 pages, 6 figures

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Optics (physics.optics)

After launching and deploying a sparse space telescope, fine tuning is required to correct for inaccurate initial placement of its elements. We selected unique shapes and locations of these telescope aperture segments, to be able to distinguish between their diffraction patterns, while at the same time having a proper spatial frequency coverage. Then we improved the combined wave front, without measuring it directly: First we correlated each segment's focal image with its distinctive template, to correct its tilt. Next we interfered them with the other segments, pair by pair, using their limited coherence, to locate their mutual optical path differences. Finally, we optimized the combined focal image for fine alignment.

[49]  arXiv:1912.00716 [pdf, other]

Title: Dark matter -- Modified dynamics: Reaction vs. Prediction

Authors: Robert H. Sanders

Comments: 18 pages, 8 figures. Contribution to the Aachen meeting on " Dark Matter and Modified gravity", Feb. 2019

Subjects: Astrophysics of Galaxies (astro-ph.GA); General Relativity and Quantum Cosmology (gr-qc)

The dark energy-cold dark matter paradigm ($\Lambda$CDM) has gained widespread acceptance because it explains the pattern of anisotropies observed in the cosmic microwave background radiation, the observed distribution of large scale inhomogeneities in detectable matter, and the perceived overall expansion history of the Universe. It is further {\it assumed} that the cosmic dark matter component clusters on the scale of bound astronomical systems and thereby accounts for the observed difference between the directly detectable (baryonic) mass and the total Newtonian dynamical mass. In this respect the paradigm fails; it is falsified by the existence of a simple algorithm, modified Newtonian dynamics (MOND), which explains, not only general scaling relations for astronomical systems, but quite precisely predicts the effective gravitational acceleration in such objects from the observed distribution of detectable baryonic matter -- all of this with one additional universal parameter having units of acceleration. On this sub-Hubble scale, the dark matter hypothesis is essentially reactive, while MOND is successfully predictive.

[50]  arXiv:1912.00729 [pdf, other]

Title: Short and long term near-infrared spectroscopic variability of eruptive protostars from VVV

Authors: Zhen Guo, P. W. Lucas, C. Contreras Peña, R. G. Kurtev, L. C. Smith, J. Borissova, J. Alonso-García, D. Minniti, A. Caratti o Garatti, D. Froebrich

Comments: 23 pages, 13 figures

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)

Numerous eruptive variable young stellar objects (YSOs), mostly Class I systems, were recently detected by the near-infrared Vista Variables in the Via Lactea (VVV) survey. We present an exploratory near-infrared spectroscopic variability study of 14 eruptive YSOs. The variations were sampled over 1-day and 1 to 2-year intervals and analysed in combination with VVV light curves. CO overtone absorption features are observed on 3 objects with FUor-like spectra: all show deeper absorption when they are brighter. This implies stronger emission from the circumstellar disc with a steeper vertical temperature gradient when the accretion rate is higher. This confirms the nature of fast VVV FUor-like events, in line with the accepted picture for classical FUors. The absence of Br$\gamma$ emission in a FUor-like object declining to pre-outburst brightness suggests that reconstruction of the stellar magnetic field is a slow process. Within the 1-day timescale, 60% of H$_2$-emitting YSOs show significant but modest variation, and 2/6 sources have large variations in Br$\gamma$. Over year-long timescales, H$_2$ flux variations remain modest despite up to 1.8 mag variation in $K_s$. This indicates that emission from the molecular outflow usually arises further from the protostar and is unaffected by relatively large changes in accretion rate on year-long timescales. Two objects show signs of on/off magnetospheric accretion traced by Br$\gamma$ emission. In addition, a 60% inter-night brightening of the H$_2$ outflow is detected in one YSO.

[51]  arXiv:1912.00732 [pdf, other]

Title: T-ReX: a graph-based filament detection method

Authors: T. Bonnaire, N. Aghanim, A. Decelle, M. Douspis

Comments: Submitted to A&A, 16 pages, 16 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

Numerical simulations and observations show that galaxies are not uniformly distributed in the universe but rather spread on a filamentary structure. In this large scale pattern, highly dense regions are linked together by bridges and walls, all of them surrounded by vast nearly-empty areas. While nodes of the network are widely studied in the literature, simulations indicate that half of the mass budget comes from a more diffuse part of the network made of filaments. In the context of recent and upcoming large galaxy surveys, it becomes essential to identify and classify features of the Cosmic Web in an automatic way to study their physical properties and the impact of the cosmic environment on galaxies and their evolution.
In this work, we propose a new approach to automatically retrieve the underlying filamentary structure from a 2D or 3D galaxy distribution using graph theory and the assumption that paths linking galaxies together with the minimum total length highlight the underlying distribution. To obtain a smoothed version of this topological prior, we embed it in a Gaussian mixtures framework. In addition to a geometrical description of the pattern, a bootstrap-like estimate of these regularized minimum spanning trees allows to obtain a map characterising the frequency at which an area of the domain is crossed. Using distribution of halos derived from numerical simulations, we show that the proposed method is able to recover the filamentary pattern in a 2D or 3D distribution of points with noise and outliers robustness with few and comprehensible parameters.

[52]  arXiv:1912.00776 [pdf, other]

Title: Localizing the $γ$-ray emitting region in the blazar TXS 2013+370

Authors: E. Traianou, T.P. Krichbaum, B. Boccardi, R. Angioni, B. Rani, J. Liu, U. Bach, K. V. Sokolovsky, S. Kiehlmann, M. Gurwell, J. A. Zensus

Comments: 16 pages, 15 figures, accepted in A&A

Subjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)

The $\gamma$-ray production mechanism and its localization in blazars are still a matter of debate. The main goal of this paper is to constrain the location of the high-energy emission in the blazar TXS 2013+370 and to study the physical and geometrical properties of the inner jet region on sub-pc scales. VLBI observations at 86 GHz and space-VLBI at 22 GHz allowed us to image the jet base with an angular resolution of $\sim$0.4 pc. By employing CLEAN imaging and Gaussian model-fitting, we performed a thorough kinematic analysis, which provided estimates of the jet speed, orientation, and component ejection times. Additionally, we studied the jet expansion profile and used the information on the jet geometry to estimate the location of the jet apex. VLBI data were combined with single-dish measurements to search for correlated activity between the radio and $\gamma$-ray emission. The high-resolution VLBI imaging revealed the existence of a spatially bent jet, described by moving and stationary features. New jet features are observed to emerge from the core, accompanied by flaring activity in radio bands and $\gamma$ rays. The analysis of the transverse jet width profile constrains the location of the mm core to lie $\leq$ 2 pc downstream of the jet apex, and also reveals the existence of a transition from parabolic to conical jet expansion at a distance of $\sim$54 pc from the core, corresponding to $\sim$1.5$\times$10$^{\rm 6}$ Schwarzschild radii. The cross-correlation analysis reveals a strong correlation between the radio and $\gamma$-ray data, with the 1 mm emission lagging $\sim$49 days behind the $\gamma$ rays. Based on this, we infer that the high energy emission is produced at a distance of $\sim$1 pc from the VLBI core, suggesting that the seed photon fields for the external Compton mechanism originate either in the dusty torus or in the broad-line region.

[53]  arXiv:1912.00828 [pdf, other]

Title: The influence of metagalactic ultra-violet background fluctuations on the high-redshift Ly$α$ forest

Authors: Avery Meiksin

Comments: 11 pages, 9 figures. Accepted for publication in MNRAS

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)

Under the assumption that galaxies and Quasi-Stellar Objects (QSOs) dominate the metagalactic ultra-violet (UV) background, it is shown that at high redshifts fluctuations in the UV background are dominated by QSO shot noise and have an auto-correlation length of a few to several comoving Mpcs, depending on the bright end of the QSO luminosity function. The correlations create long range spatial coherence in the neutral hydrogen fraction. Using a semi-analytic model, it is demonstrated that the coherence may account for the broad distribution in effective optical depths measured in the Ly$\alpha$ forest spectra of background QSOs, for line-of-sight segments of comoving length $50h^{-1}$ Mpc at redshifts $5<z<6$. Capturing the fluctuations in a numerical simulation requires a comoving box size of $\sim1h^{-1}$ Gpc, although a box half this size may be adequate if sufficient random realizations of the QSO population are performed.

[54]  arXiv:1912.00844 [pdf]

Title: Solar Elemental Abundances

Authors: Katharina Lodders

Comments: review paper

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)

Review of the history of solar system elemental abundances with a new assessment of elemental and isotopic abundances from CI-chondrites and solar data. Solar elemental abundances, or solar system elemental abundances refer to the complement of chemical elements in the entire solar system. The sun contains more than 99-percent of the mass in the solar system and therefore the composition of the sun is a good proxy for the composition of the overall solar system. The solar system composition can be taken as the overall composition of the molecular cloud within the interstellar medium from which the solar system formed 4.567 billion years ago. Active research areas in astronomy and cosmochemistry model collapse of a molecular cloud of solar composition into a star with a planetary system, and the physical and chemical fractionation of the elements during planetary formation and differentiation. The solar system composition is the initial composition from which all solar system objects (the sun, terrestrial planets, gas giant planets, planetary satellites and moons, asteroids, Kuiper-belt objects, and comets) were derived. (Abstract truncated).

[55]  arXiv:1912.00859 [pdf, ps, other]

Title: Continuum enhancements, line profiles and magnetic field evolution during consecutive flares

Authors: Francesca Zuccarello, Salvo L. Guglielmino, Vincenzo Capparelli, Mihalis Mathioudakis, Peter H. Keys, Serena Criscuoli, Mariachiara Falco, Mariarita Murabito

Comments: 19 pages, accepted for ApJ; some figures are in B/W to accomplish size limits

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Space Physics (physics.space-ph)

During solar flares, magnetic energy can be converted into electromagnetic radiation from radio waves to $\gamma$ rays. Enhancements in the continuum at visible wavelengths give rise to white-light flares, as well as continuum enhancements in the FUV and NUV passbands. In addition, the strong energy release in these events can lead to the rearrangement of the magnetic field at the photospheric level, causing morphological changes in large and stable magnetic structures like sunspots. In this context, we describe observations acquired by satellite instruments (IRIS, SDO/HMI, Hinode/SOT) and ground-based telescopes (ROSA/DST) during two consecutive C7.0 and X1.6 flares occurred in active region NOAA 12205 on 2014 November 7. The flare was accompanied by an eruption. The results of the analysis show the presence of continuum enhancements during the evolution of the events, observed both in ROSA images and in \textit{IRIS} spectra. In the latter, a prominent blue-shifted component is observed at the onset of the eruption. We investigate the role played by the evolution of the $\delta$ sunspots of the active region in the flare triggering, and finally we discuss the changes in the penumbrae surrounding these sunspots as a further consequence of these flares.

[56]  arXiv:1912.00860 [pdf, other]

Title: Characterization of Transition Edge Sensors for the Simons Observatory

Authors: Jason R. Stevens, Nicholas F. Cothard, Eve M. Vavagiakis, Aamir Ali, Kam Arnold, Jason E. Austermann, Steve K. Choi, Bradley J. Dober, Cody Duell, Shannon M. Duff, Gene C. Hilton, Shuay-Pwu Patty Ho, Thuong D. Hoang, Johannes Hubmayr, Adrian T. Lee, Aashrita Mangu, Federico Nati, Michael D. Niemack, Christopher Raum, Mario Renzullo, Maria Salatino, Trevor Sasse, Sara M. Simon, Suzanne Staggs, Aritoki Suzuki, Patrick Truitt, Joel Ullom, John Vivalda, Michael R. Vissers, Samantha Walker, Benjamin Westbrook, Edward J. Wollack, Zhilei Xu, Daniel Yohannes

Comments: 8 Pages, 5 figures, Low Temperature Detectors 19

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)

The Simons Observatory is building both large (6 m) and small (0.5 m) aperture telescopes in the Atacama desert in Chile to observe the cosmic microwave background (CMB) radiation with unprecedented sensitivity. Simons Observatory telescopes in total will use over 60,000 transition edge sensor (TES) detectors spanning center frequencies between 27 and 285 GHz and operating near 100 mK. TES devices have been fabricated for the Simons Observatory by NIST, Berkeley, and HYPRES/SeeQC corporation. Iterations of these devices have been tested cryogenically in order to inform the fabrication of further devices, which will culminate in the final TES designs to be deployed in the field. The detailed design specifications have been independently iterated at each fabrication facility for particular detector frequencies. We present test results for prototype devices, with emphasis on NIST high frequency detectors. A dilution refrigerator was used to achieve the required temperatures. Measurements were made both with 4-lead resistance measurements and with a time domain Superconducting Quantum Interference Device (SQUID) multiplexer system. The SQUID readout measurements include analysis of current vs voltage (IV) curves at various temperatures, square wave bias step measurements, and detector noise measurements. Normal resistance, superconducting critical temperature, saturation power, thermal and natural time constants, and thermal properties of the devices are extracted from these measurements.

[57]  arXiv:1912.00868 [pdf, other]

Title: Unveiling the singular dynamics in the cosmic large-scale structure

Authors: Cornelius Rampf, Uriel Frisch, Oliver Hahn

Comments: 5 pages + references, 2 figures, to be submitted to PRL (the accompanied numerical code can be downloaded from this https URL)

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Adaptation and Self-Organizing Systems (nlin.AO)

Gravitational collapse of cold dark matter leads to infinite-density caustics that seed the primordial dark-matter halos in the large-scale structure. The development of these caustics begins, generically, as an almost one-dimensional phenomenon with the formation of pancakes. Focusing on the one-dimensional case, we identify a landscape of so far unknown singularities in the particle acceleration that emerge after the first crossing of particle trajectories. We complement our fully analytical studies by high-resolution N-body simulations and find outstanding agreement, particularly shortly after the first crossing. We develop the methods in 1D but outline briefly the necessary steps for the 3D case.

[58]  arXiv:1912.00885 [pdf, other]

Title: Scalar Induced Gravitational Waves in Different Gauges

Authors: Chen Yuan, Zu-Cheng Chen, Qing-Guo Huang

Comments: 2 figures, 8 pages

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)

In this letter we calculate the scalar induced gravitational waves (SIGWs) accompanying the formation of primordial black hole during the radiation dominated era in three different gauges, i.e. synchronous gauge, Newton gauge and uniform curvature gauge. The energy density spectra of SIGWs, $\Omega_{\rm GW}(k)$, are identical in these three different gauges for the $\delta$-power spectrum of scalar perturbation, and remain the same in the infrared region for a broad power spectrum.

[59]  arXiv:1912.00917 [pdf, ps, other]

Title: Web SAMP and HTTPS: What to do?

Authors: M. B. Taylor

Comments: 4 pages, 1 figure; to appear in proceedings of ADASS 2019, ASP Conference Series

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)

SAMP, the Simple Application Messaging Protocol, is a standard developed within the Virtual Observatory to allow communication between different software items on the desktop. One popular usage scenario has been enabling one-click transmission of a table or FITS image from a web page, typically an archive search result of some kind, to a desktop application such as TOPCAT, Aladin or ds9. This has worked well for HTTP web pages since the introduction of the SAMP Web Profile in SAMP 1.3, but the Web Profile will not work over HTTPS, which is increasingly being adopted by data providers.
This paper presents a summary of the problem and explores some possible ways forward, for which working prototypes have been developed: specify a new HTTPS-capable Profile, use a SAMP-capable helper application, or abandon using SAMP over HTTPS.

[60]  arXiv:1912.00918 [pdf, other]

Title: Colour and Tropospheric Cloud Structure of Jupiter from MUSE/VLT: Retrieving a Universal Chromophore

Authors: Ashwin S. Braude, Patrick G. J. Irwin, Glenn S. Orton, Leigh N. Fletcher

Comments: 14 figures + 4 tables, preprint accepted by Icarus on the 29th of November 2019

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Atmospheric and Oceanic Physics (physics.ao-ph)

Recent work by Sromovsky et al. (2017, Icarus 291, 232-244) suggested that all red colour in Jupiter's atmosphere could be explained by a single colour-carrying compound, a so-called 'universal chromophore'. We tested this hypothesis on ground-based spectroscopic observations in the visible and near-infrared (480-930 nm) from the VLT/MUSE instrument between 2014 and 2018, retrieving a chromophore absorption spectrum directly from the North Equatorial Belt, and applying it to model spatial variations in colour, tropospheric cloud and haze structure on Jupiter. We found that we could model both the belts and the Great Red Spot of Jupiter using the same chromophore compound, but that this chromophore must exhibit a steeper blue-absorption gradient than the proposed chromophore of Carlson et al. (2016, Icarus 274, 106-115). We retrieved this chromophore to be located no deeper than 0.2+/-0.1 bars in the Great Red Spot and 0.7+/-0.1 bars elsewhere on Jupiter. However, we also identified some spectral variability between 510 nm and 540 nm that could not be accounted for by a universal chromophore. In addition, we retrieved a thick, global cloud layer at 1.4+/-0.3 bars that was relatively spatially invariant in altitude across Jupiter. We found that this cloud layer was best characterised by a real refractive index close to that of ammonia ice in the belts and the Great Red Spot, and poorly characterised by a real refractive index of 1.6 or greater. This may be the result of ammonia cloud at higher altitude obscuring a deeper cloud layer of unknown composition.

[61]  arXiv:1912.00925 [pdf, other]

Title: Multiband RadioAstron space VLBI imaging of the jet in quasar S5 0836+710

Authors: L. Vega-García, A. P. Lobanov, M. Perucho, G. Bruni, E. Ros, J.M. Anderson, I. Agudo, R. Davis, J.L. Gómez, Y.Y. Kovalev, T.P. Krichbaum, M. Lisakov, T. Savolainen, J.A. Zensus

Comments: 16 pages, 9 figures (9 extra figures in Appendix), in press; Astronomy and Astrophysics

Subjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)

Detailed studies of relativistic jets in active galactic nuclei (AGN) require high-fidelity imaging at the highest possible resolution. This can be achieved using very long baseline interferometry (VLBI) at radio frequencies, combining worldwide (global) VLBI arrays of radio telescopes with a space-borne antenna on board a satellite. We present multiwavelength images made of the radio emission in the powerful quasar S5 0836+710, obtained using a global VLBI array and the antenna Spektr-R of the RadioAstron mission of the Russian Space Agency, with the goal of studying the internal structure and physics of the relativistic jet in this object. The RadioAstron observations at wavelengths of 18cm, 6cm, and 1.3cm are part of the Key Science Program for imaging radio emission in strong AGN. The internal structure of the jet is studied by analyzing transverse intensity profiles and modeling the structural patterns developing in the flow. The RadioAstron images reveal a wealth of structural detail in the jet of S5 0836+710 on angular scales ranging from 0.02mas to 200mas. Brightness temperatures in excess of $10^{13}$\,K are measured in the jet, requiring Doppler factors of $\ge 100$ for reconciling them with the inverse Compton limit. Several oscillatory patterns are identified in the ridge line of the jet and can be explained in terms of the Kelvin-Helmholtz (KH) instability. The oscillatory patterns are interpreted as the surface and body wavelengths of the helical mode of the KH instability. The interpretation provides estimates of the jet Mach number and of the ratio of the jet to the ambient density, which are found to be $M_\mathrm{j}\approx 12$ and $\eta\approx 0.33$. The ratio of the jet to the ambient density should be conservatively considered an upper limit because its estimate relies on approximations.

[62]  arXiv:1912.00934 [pdf, other]

Title: Cosmic evolution of star-forming galaxies to $z \simeq 1.8$ in the faint low-frequency radio source population

Authors: E. F. Ocran, A. R. Taylor, M. Vaccari, C.H. Ishwara-Chandra, I. Prandoni, M. Prescott, C. Mancuso

Comments: 16 pages, 11 figures and 6 tables in the main text plus additional figure and table in the appendix. Accepted for publication in MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We study the properties of star-forming galaxies selected at 610 MHz with the GMRT in a survey covering $\sim$1.86 deg$^2$ down to a noise of $\sim$7.1\,$\mu$Jy / beam. These were identified by combining multiple classification diagnostics: optical, X-ray, infrared and radio data.
Of the 1685 SFGs from the GMRT sample, 496 have spectroscopic redshifts whereas 1189 have photometric redshifts. We find that the IRRC of star-forming galaxies, quantified by the infrared-to-1.4 GHz radio luminosity ratio $\rm{q_{IR}}$, decreases with increasing redshift: $\rm{q_{IR}\,=\,2.86\pm0.04(1\,+\,z)^{-0.20\pm0.02}}$ out to $z \sim 1.8$. We use the $\rm{V/V_{max}}$ statistic to quantify the evolution of the co-moving space density of the SFG sample. Averaged over luminosity our results indicate $\rm{\langle V/V_{max} \rangle}$ to be $\rm{0.51\,\pm\, 0.06}$, which is consistent with no evolution in overall space density. However we find $\rm V/V_{max}$ to be a function of radio luminosity, indicating strong luminosity evolution with redshift.
We explore the evolution of the SFGs radio luminosity function by separating the source into five redshift bins and comparing to theoretical model predictions. We find a strong redshift trend that can be fitted with a pure luminosity evolution of the form $\rm{L_{610\,MHz}\,\propto\,(\,1+\,z)^{(2.95\pm0.19)-(0.50\pm0.15)z}}$. We calculate the cosmic SFR density since $\rm{z \sim 1.5}$ by integrating the parametric fits of the evolved 610\,MHz luminosity function. Our sample reproduces the expected steep decline in the star formation rate density since $\rm{z\,\sim\,1}$.

[63]  arXiv:1912.00940 [pdf, other]

Title: Gravimeter search for compact dark matter objects moving in the Earth

Authors: C. J. Horowitz, R. Widmer-Schnidrig

Comments: 8 pages, 7 figures

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph); Nuclear Theory (nucl-th)

Dark matter could be composed of compact dark objects (CDOs). These objects may interact very weakly with normal matter and could move freely {\it inside} the Earth. A CDO moving in the inner core of the Earth will have an orbital period near 55 min and produce a time dependent signal in a gravimeter. Data from superconducting gravimeters rule out such objects moving inside the Earth unless their mass $m_D$ and or orbital radius $a$ are very small so that $m_D\, a < 1.2\times 10^{-13}M_\oplus R_\oplus$. Here $M_\oplus$ and $R_\oplus$ are the mass and radius of the Earth.

[64]  arXiv:1912.00987 [pdf, other]

Title: Constraints on the Diffuse Flux of Ultra-High Energy Neutrinos from Four Years of Askaryan Radio Array Data in Two Stations

Authors: ARA Collaboration: P. Allison, S. Archambault, J.J. Beatty, M. Beheler-Amass, D.Z. Besson, M. Beydler, C.C. Chen, C.H. Chen, P. Chen, B.A. Clark, W. Clay, A. Connolly, L. Cremonesi, J. Davies, S. de Kockere, K.D. de Vries, C. Deaconu, M. Duvernois, E. Friedman, R. Gaior, J. Hanson, K. Hanson, K.D. Hoffman, B. Hokanson-Fasig, E. Hong, S.Y. Hsu, L. Hu, J.J. Huang, M.-H. Huang, K. Hughes, A. Ishihara, A. Karle, J.L. Kelley, R. Khandelwal, K.-C. Kim, M.-C. Kim, I. Kravchenko, K. Kurusu, H. Landsman, U.A. Latif, A. Laundrie, C.-J. Li, T.-C. Liu, M.-Y. Lu, B. Madison, K. Mase, T. Meures, J. Nam, R.J. Nichol, G. Nir, A. Novikov, A. Nozdrina, E. Oberla, A. O'Murchadha, J. Osborn, Y. Pan, C. Pfendner, J. Roth, P. Sandstrom, D. Seckel, Y.-S. Shiao, A. Shultz, D. Smith, J. Torres, J. Touart, N. van Eijndhoven, et al. (7 additional authors not shown)

Comments: 12 pages, 7 figures

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM)

The Askaryan Radio Array is an ultra-high energy (UHE, $>10^{17}$\,eV) neutrino detector designed to observe neutrinos by searching for the radio waves emitted by the relativistic byproducts of neutrino-nucleon interactions in Antarctic ice. In this paper, we present constraints on the diffuse flux of ultra-high energy neutrinos between $10^{16}-10^{21}$\,eV resulting from a search for neutrinos in two complementary analyses, both analyzing four years of data (2013-2016) from the two deep stations (A2, A3) operating at that time. We place a 90\% CL upper limit on the diffuse neutrino flux at $10^{18}$ eV of $EF(E)=3.9\times10^{-16}$~$\textrm{cm}^2$$\textrm{s}^{-1}$$\textrm{sr}^{-1}$. The analysis leverages more than quadruple the livetime of the previous ARA limit, and at this energy is the most sensitive reported by an in-ice radio neutrino detector by more than a factor of four. Looking forward, ARA has yet to analyze more than half of its archived data, and expects that dataset to double in size in the next three years as livetime accumulates in the full five-station array. With this additional livetime, we project ARA will have world-leading sensitivity to neutrinos above $10^{17}$ eV by 2022.

[65]  arXiv:1912.00994 [pdf, other]

Title: Massive black holes regulated by luminous blue variable mass loss and magnetic fields - implications for the progenitor of LB-1

Authors: Jose H. Groh, Eoin Farrell, Georges Meynet, Nathan Smith, Laura Murphy, Andrew Allan

Comments: Submitted to ApJL

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE)

We investigate the effects of mass loss during the main-sequence (MS) and post-MS phases on the final black hole (BH) masses of massive stars. We compute solar metallicity Geneva stellar evolution models of an 85 $M_\odot$ star with mass-loss rate ($M_\odot$) prescriptions for MS and post-MS phases. Such models could lead to massive BHs such as the recently detected 70 $M_\odot$ BH in the LB-1 system. Based on the observational constraints for $M_\odot$ of luminous stars, we discuss two possible scenarios that could produce such a massive BH at high metallicity. First, if the progenitor of LB-1 evolved from the observed population of WNh stars, we show that its average mass loss rate during its post-MS evolution was less than $1\,\times10^{-5}\,M_\odot/$yr. However, this is lower than the typical observed mass-loss rates of LBVs. A second possibility is that the progenitor evolved from a yet undetected population of 80-85~\msun\ stars with strong surface magnetic fields, which could quench mass loss during the MS evolution. In this case, the average mass-loss rate during the post-MS luminous blue variable (LBV) phase has to be less than $5\,\times10^{-5}\,M_\odot/$yr. This value is still low, considering that LBVs such as AG Carinae typically have average mass-loss rates from quiescent stellar winds close or above this level. LBVs directly collapsing to massive BHs are apparently at odds with the evidence that LBVs are the direct progenitors of some supernovae (SNe). To reconcile this, we suggest that LBVs from single stars (or mergers that fully mixed) have large cores and form BHs, while binary LBVs may have smaller cores and larger envelopes (either mergers or mass gainers that do not fully mix) and could produce a SN.

[66]  arXiv:1912.00995 [pdf, other]

Title: How much primordial tensor mode is allowed?

Authors: Moumita Aich, Yin-Zhe Ma, Wei-Ming Dai, Jun-Qing Xia

Comments: 12 pages, 7 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

The presence of a significant amount of gravitational radiation in the early Universe affects the total energy density and hence the expansion rate in the early epoch. In this work, we develop a physical model to connect the parameter of relativistic degree of freedom $N_\mathrm{eff}$ with the amplitude and shape of primordial tensor power spectrum, and use the CMB temperature and polarization data from {\it Planck} and BICEP2/KECK Array, and the primordial deuterium measurement from damped Lyman-$\alpha$ (DLA) systems to constrain this model. We find that with this extra relation $\Delta N_{\rm eff}(r,n_{\rm t})$, the tensor-to-scalar ratio $r$ is constrained to be $r<0.07$ ($3\sigma$ C.L.) and the tilt of tensor power spectrum is $n_\mathrm{t}=-0.01\pm 0.31$ ($1\sigma$ C.L.) for {\it Planck}+BICEP2+KECK+[D/H] data. This achieves a much tighter constraint on the tensor spectrum and provides a stringent test for cosmic inflation models. In addition, the current constraint on $N_{\rm eff}=3.122 \pm 0.171$ excludes the possibility of fourth neutrino species at more than $5\sigma$ C.L.

[67]  arXiv:1912.00997 [pdf, other]

Title: Constraining strongly supercooled phase transitions by overproduction of black holes

Authors: Marek Lewicki, Ville Vaskonen

Comments: 6 pages, 5 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)

We study the formation of black holes from bubble collisions in cosmological first order phase transitions. We show that if false vacuum bubbles are formed in these collisions, new very strong constraints can be put on models due to overproduction of black holes.

[68]  arXiv:1912.00999 [pdf, other]

Title: Globular clusters in the stellar stream surrounding the Milky Way analog NGC 5907

Authors: Adebusola B. Alabi, Duncan A. Forbes, Aaron J. Romanowsky, Jean P. Brodie

Comments: 9 pages, 9 figures, catalog of GCs is available in online version

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We study the globular clusters (GCs) in the spiral galaxy NGC~5907 well-known for its spectacular stellar stream -- to better understand its origin. Using wide-field Subaru/Suprime-Cam $gri$ images and deep Keck/DEIMOS multi-object spectroscopy, we identify and obtain the kinematics of several GCs superimposed on the stellar stream and the galaxy disk. We estimate the total number of globular clusters in NGC 5907 to be $154\pm44$, with a specific frequency of $0.73\pm0.21$. Our analysis also reveals a significant, new population of young star cluster candidates found mostly along the outskirts of the stellar disk. Using the properties of the stream GCs, we estimate that the disrupted galaxy has a stellar mass similar to the Sagittarius dwarf galaxy accreted by the Milky Way, i.e. $\sim10^8~M_\odot$.

Cross-lists for Tue, 3 Dec 19

[69]  arXiv:1909.07776 (cross-list from hep-th) [pdf, ps, other]

Title: Thermodynamical hairs of the four-dimensional Taub-Newman-Unti-Tamburino spacetimes

Authors: Shuang-Qing Wu, Di Wu

Comments: 7 pages, twocolumn, revtex4-1. Matched with published version; Ref.[32] is contained in the source file of 1909.07776v1

Journal-ref: Phys. Rev. D 100 (2019) 101501(R)

Subjects: High Energy Physics - Theory (hep-th); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)

It is demonstrated that the generic four-dimensional Taub-Newman-Unti-Tamburino (Taub-NUT) spacetimes can be perfectly described in terms of three or four different kinds of thermodynamic hairs: the Komar mass ($M = m$), the "angular momentum" ($J_n = mn$), the gravitomagnetic charge ($N = n$), and/or the dual (magnetic) mass ($\widetilde{M} = n$). In other words, the NUT charge is a thermodynamic multihair which means that it simultaneously has both rotation-like and electromagnetic charge-like characteristics; this is in sharp contrast with the previous knowledge that it has only one physical feature, or that it is purely a single solution parameter. To arrive at this novel result, we put forward a simple, systematic way to investigate the consistent thermodynamic first law and Bekenstein-Smarr mass formulas of all four-dimensional spacetimes that contain a nonzero NUT charge, facilitated by first deriving a meaningful Christodoulou-Ruffini-type squared-mass formula. In this way, not only can the elegant Bekenstein-Hawking one-quarter area-entropy relation be naturally restored in the Lorentzian and Euclidian sectors of generic Taub-NUT-type spacetimes without imposing any constraint condition, but also the physical meaning of the NUT parameter as a poly-facet can be completely clarified in the thermodynamic sense for the first time.

[70]  arXiv:1911.04502 (cross-list from hep-ph) [pdf, other]

Title: Scalar gauge dynamics and Dark Matter

Authors: Dario Buttazzo, Luca Di Luzio, Parsa Ghorbani, Christian Gross, Giacomo Landini, Alessandro Strumia, Daniele Teresi, Jin-Wei Wang

Comments: 50 pages, 5 figures, 3 tables

Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)

We consider theories with one gauge group (SU, SO or Sp) and one scalar in a two-index representation. The renormalizable action often has accidental symmetries (such as global U(1) or unusual group parities) that lead to one or more stable states, providing Dark Matter candidates. We discuss the confined phase(s) of each theory and compute the two Higgs phases, finding no generic dualities among them. Discrete gauge symmetries can arise and accidental symmetries can be broken, possibly giving pseudo-Goldstone Dark Matter. Dark Matter candidates can have a complicated sub-structure characteristic of each group and can be accompanied by extra dark radiation.

[71]  arXiv:1911.13199 (cross-list from gr-qc) [pdf, other]

Title: Homogeneity and the causal boundary

Authors: Enrique Gaztanaga

Comments: 10 pages, 2 figures, invited review at XXXIX Polish Astronomical Society Meeting. arXiv admin note: text overlap with arXiv:1904.08218

Journal-ref: Contribution to the Proceedings of the XXXIX Polish Astronomical (09-12 September 2019, Olsztyn, Poland)

Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th); History and Philosophy of Physics (physics.hist-ph)

A Universe with finite age also has a finite causal scale $\chi_\S$, so the metric can not be homogeneous for $\chi>\chi_\S$, as it is usually assumed. To account for this, we propose a new causal boundary condition, that can be fulfil by fixing the cosmological constant $\Lambda$ (a free parameter for gravity). The resulting Universe is inhomogeneous, with possible variation of cosmological parameters on scales $\chi \simeq \chi_\S$. The size of $\chi_\S$ depends on the details of inflation, but regardless of its size, the boundary condition forces $\Lambda/8\pi G $ to cancel the contribution of a constant vacuum energy $\rho_{vac}$ to the measured $\rho_\Lambda \equiv \Lambda/8\pi G + \rho_{vac}$. To reproduce the observed $\rho_{\Lambda} \simeq 2 \rho_m$ today with $\chi_\S \rightarrow \infty$ we then need a universe filled with evolving dark energy (DE) with pressure $p_{DE}> - \rho_{DE}$ and a fine tuned value of $\rho_{DE} \simeq 2 \rho_m$ today. This seems very odd, but there is another solution to this puzzle. We can have a finite value of $\chi_\S \simeq 3 c/H_0$ without the need of DE. This scale corresponds to half the sky at $z \sim 1$ and 60deg at $z \sim 1000$, which is consistent with the anomalous lack of correlations observed in the CMB.

[72]  arXiv:1912.00114 (cross-list from physics.comp-ph) [pdf, other]

Title: The computation of seismic normal modes with rotation as a quadratic eigenvalue problem

Authors: Jia Shi, Ruipeng Li, Yuanzhe Xi, Yousef Saad, Maarten V. de Hoop

Subjects: Computational Physics (physics.comp-ph); Earth and Planetary Astrophysics (astro-ph.EP)

A new approach is presented to compute the seismic normal modes of a fully heterogeneous, rotating planet. Special care is taken to separate out the essential spectrum in the presence of a fluid outer core. The relevant elastic-gravitational system of equations, including the Coriolis force, is subjected to a mixed finite-element method, while self-gravitation is accounted for with the fast multipole method (FMM). To solve the resulting quadratic eigenvalue problem (QEP), the approach utilizes extended Lanczos vectors forming a subspace computed from a non-rotating planet -- with the shape of boundaries of a rotating planet and accounting for the centrifugal potential -- to reduce the dimension of the original problem significantly. The subspace is guaranteed to be contained in the space of functions to which the seismic normal modes belong. The reduced system can further be solved with a standard eigensolver. The computational accuracy is illustrated using all the modes with relative small meshes and also tested against standard perturbation calculations relative to a standard Earth model. The algorithm and code are used to compute the point spectra of eigenfrequencies in several Mars models studying the effects of heterogeneity on a large range of scales.

[73]  arXiv:1912.00242 (cross-list from hep-th) [pdf, other]

Title: $H_0$ tension and the String Swampland

Authors: Luis A. Anchordoqui, Ignatios Antoniadis, Dieter Lust, Jorge F. Soriano, Tomasz R. Taylor

Subjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)

We realize the Agrawal-Obied-Vafa swampland proposal of fading dark matter for solving the $H_0$ tension by the model of Salam-Sezgin and its string realization of Cvetic-Gibbons-Pope. The model describes a compactification of six-dimensional supergravity with a monopole background on a 2-sphere. In four dimensions, there are two scalar fields, $X$ and $Y $, and the effective potential in the Einstein frame is an exponential with respect to $Y$ times a quadratic polynomial in the field $e^{-X}$. When making the volume of the 2-sphere large, namely for large values of $Y$, there appears a tower of states, which according to the infinite distance swampland conjecture becomes exponentially massless. We confront the model with recent cosmological observations. We show that this set up is well equipped to explain the overall data even when considering local measurements of $H_0$, and that it can potentially ameliorate the tension between low-redshift observations and measurements of the cosmic microwave background. Indeed, the tower of string states that emerges from the rolling of $Y$ constitutes a portion of the dark matter, and the way in which the $X$ particle and its KK excitations evolve over time (refer to as fading dark matter) is responsible for reducing the $H_0$ tension.

[74]  arXiv:1912.00252 (cross-list from cond-mat.stat-mech) [pdf]

Title: Emergence of modified Newtonian gravity from thermodynamics

Authors: Péter Ván, Sumiyoshi Abe

Comments: 18 pages, 1 figure

Subjects: Statistical Mechanics (cond-mat.stat-mech); Astrophysics of Galaxies (astro-ph.GA); General Relativity and Quantum Cosmology (gr-qc); Classical Physics (physics.class-ph)

Being inspired by Verlinde's proposal that general relativistic gravity has a thermodynamic origin as an entropic force, Newtonian gravity is reexamined in view of nonequilibrium thermodynamics. Here, firstly, an unspecified scalar field potential is introduced and treated as a thermodynamic variable on an equal footing with the fluid variables. Then, the effects of irreversibility on the field are explored through the analysis of the entropy production rate in the linear regime. Remarkably, the second law of thermodynamics imposes a stringent constraint on the allowable field, which turns out to be of gravity. The resulting field equation for the gravitational potential contains a dissipative term originating from irreversibility. It is found that the system relaxes to the conventional theory of Newtonian gravity up to a certain spatial scale (typically the solar scale), whereas on the larger scale (such as the galaxy scale) a potential needed in Modified Newtonian Dynamics (MOND) naturally appears. A comment is made on an implication of the result to the astrophysical phenomenon regarding dark matter.

[75]  arXiv:1912.00378 (cross-list from gr-qc) [pdf, ps, other]

Title: Weakly-coupled stealth solution in scordatura degenerate theory

Authors: Hayato Motohashi, Shinji Mukohyama

Comments: 16 pages

Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)

In scalar-tensor theories we revisit the issue of strong coupling of perturbations around stealth solutions, i.e.\ backgrounds with the same forms of the metric as in General Relativity but with non-trivial configurations of the scalar field. The simplest among them is a stealth Minkowski (or de Sitter) solution with a constant, timelike derivative of the scalar field, i.e.\ ghost condensation. In the decoupling limit the effective field theory (EFT) describing perturbations around the stealth Minkowski (or de Sitter) solution shows the universal dispersion relation of the form $\omega^2 = \alpha k^4/M^2$, where $M$ is a mass scale characterizing the background scalar field and $\alpha$ is a dimensionless constant. Provided that $\alpha$ is positive and of order unity, a simple scaling argument shows that the EFT is weakly coupled all the way up to $M$. On the other hand, if the structure of the underlining theory forces the perturbations to follow second-order equations of motion then $\alpha=0$ and the dispersion relation loses dependence on the spatial momentum. This not only explains the origin of the strong coupling problem that was recently pointed out in a class of degenerate theories but also provides a hint for a possible solution of the problem. We then argue that a controlled detuning of the degeneracy condition, which we call scordatura, renders the perturbations weakly coupled without changing the properties of the stealth solutions of degenerate theories at astrophysical scales.

[76]  arXiv:1912.00395 (cross-list from physics.bio-ph) [pdf, ps, other]

Title: Similarities between Insect Swarms and Isothermal Globular Clusters

Authors: Dan Gorbonos, Kasper van der Vaart, Michael Sinhuber, James G. Puckett, Nicholas T. Ouellette, Andrew M. Reynolds, Nir S. Gov

Subjects: Biological Physics (physics.bio-ph); Solar and Stellar Astrophysics (astro-ph.SR); Statistical Mechanics (cond-mat.stat-mech)

Previous work has suggested that disordered swarms of flying insects can be well modeled as self-gravitating systems, as long as the "gravitational" interaction is adaptive. Motivated by this work we compare the predictions of the classic, mean-field King model for isothermal globular clusters to observations of insect swarms. Detailed numerical simulations of regular and adaptive gravity allow us to expose the features of the swarms' density profiles that are captured by the King model phenomenology, and those that are due to adaptivity and short-range repulsion. Our results provide further support for adaptive gravity as a model for swarms.

[77]  arXiv:1912.00404 (cross-list from hep-ph) [pdf, other]

Title: Probing Electroweak Dark Matter at 14 TeV LHC

Authors: Shuai Xu, Sibo Zheng

Comments: Revtex, 9 pp

Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Experiment (hep-ex)

Well-motivated electroweak dark matter is often hosted by an extended electroweak sector which also contains new lepton pairs with masses near the weak scale. In this paper, we explore such electroweak dark matter via combining dark matter direct detections and high-luminosity LHC probes of new lepton pairs. Using $Z$- and $W$-associated electroweak processes $pp \to \ell_\alpha^\pm \ell_\beta^\pm+ E_T^{\rm miss}$, $pp \to \ell_\alpha^\pm \ell_\beta^\pm jj + E_T^{\rm miss}$ and $pp \to \ell_\alpha^\pm \ell_\beta^\pm \ell_\gamma^\pm + E_T^{\rm miss}$, where the lepton pairs decay to on-shell $Z$ and/or $W$, we show that dependent on the overall coupling constant, dark matter mass up to $170-210$ GeV can be excluded at $2\sigma$ level and up to $175-205$ GeV can be discovered at $5\sigma$ level at the 14 TeV LHC with integrated luminosities 300 fb$^{-1}$ and 3000 fb$^{-1}$, respectively.

[78]  arXiv:1912.00443 (cross-list from hep-ph) [pdf, other]

Title: Constraints on Dark Matter from the Moon

Authors: Raghuveer Garani, Peter Tinyakov

Comments: 8 pages

Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Earth and Planetary Astrophysics (astro-ph.EP); High Energy Astrophysical Phenomena (astro-ph.HE)

New and complimentary constraints are placed on the spin-independent interactions of dark matter with baryonic matter. Similar to the Earth and other planets, the Moon does not have any major internal heat source. We derive constraints by comparing the rate of energy deposit by dark matter annihilations in the Moon to 12 mW/m$^2$ as measured by the Apollo mission. For light dark matter of mass $\mathcal{O}(10)$ GeV, we also examine the possibility of dark matter annihilations in the Moon limb. In this case, we place constraints by comparing the photon flux from such annihilations to that of the Fermi-LAT measurement of $10^{-4}$ MeV/cm$^2$s. This analysis excludes spin independent cross section $\gtrsim 10^{-37}$ $\rm{cm}^2$ for dark matter mass between 30 and 50 GeV.

[79]  arXiv:1912.00475 (cross-list from gr-qc) [pdf, ps, other]

Title: Constant-roll $k$-Inflation Dynamics

Authors: S.D. Odintsov, V.K. Oikonomou

Comments: CQG Accepted

Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)

In this work we shall investigate the phenomenological implications of the constant-roll condition on a $k$-Inflation theory of gravity. The latter theories are particularly promising, since these remained robust to the results of GW170817, since these have a gravitational wave speed $c_T=1$ in natural units. We shall mainly focus on the phenomenology of the $k$-Inflation models, with the only assumption being the slow-roll condition imposed on the first and fourth slow-roll parameters, and the constant-roll condition for the evolution of the scalar field. We present in detail the final form of the gravitational equations of motion that control the dynamics of the cosmological system, with the constant-roll condition imposed, and by using a conveniently, from the perspective of analytical manipulations, chosen potential, we express the slow-roll indices and the resulting observational indices of the theory as functions of the $e$-foldings number. The results of our analysis indicate that the constant-roll $k$-Inflation theory can be compatible with the Planck 2018 data, for a wide range of the free parameters. Also we examine in a quantitative way the effects of the constant-roll condition on the parameter $f_{NL}^{equil}$ on which the bispectrum is proportional, in the equilateral momentum approximation, and we demonstrate that the effect of the constant-roll condition is non-trivial. In effect, non-Gaussianities in the theory may be enhanced, a phenomenon which is known to be produced by constant-roll scalar theories of gravity in general.

[80]  arXiv:1912.00491 (cross-list from hep-ph) [pdf, other]

Title: Reconnection of magnetic fields in neutron stars driven by the electron mass term in the triangle anomaly

Authors: Maxim Dvornikov, Victor B. Semikoz (IZMIRAN)

Comments: 6 pages in pdflatex, 1 pdf figure; contribution to the proceedings of the 4th International conference on particle physics and astrophysics (October 22-26, 2018, Moscow, Russia)

Journal-ref: J. Phys.: Conf. Ser. 1390, 012079 (2019)

Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE)

The Adler-Bell-Jackiw anomaly for massive particles is studied in an external magnetic field. The contributions of the mean spin and the pseudoscalar are accounted for in the quasiclassical approximation. The equation for the evolution of the magnetic helicity with the new quantum corrections is derived. We show that the quantum contribution to the helicity evolution can overcome the classical one in the dense degenerate matter which can be present in the core of a neutron star. The application of the obtained results for the interpretation of magnetar bursts are discussed.

[81]  arXiv:1912.00591 (cross-list from gr-qc) [pdf, ps, other]

Title: Tidal forces are gravitational waves

Authors: Rituparno Goswami, George F. R. Ellis

Comments: 9 pages, revtex4

Subjects: General Relativity and Quantum Cosmology (gr-qc); Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)

In this paper we show in a covariant and gauge invariant way that in general relativity, tidal forces are actually a hidden form of gravitational waves. This must be so because gravitational effects cannot occur faster than the speed of light. Any two body gravitating system, where the bodies are orbiting around each other, may generate negligible gravitational waves, but it is via these waves that non-negligible tidal forces (causing shape distortions) act on these bodies. Although the tidal forces are caused by the electric part of the Weyl tensor, we transparently show that some small time varying magnetic part of the Weyl tensor with non zero curl must be present in the system that mediates the tidal forces via gravitational wave type effects.

[82]  arXiv:1912.00607 (cross-list from hep-th) [pdf, ps, other]

Title: A refined trans-Planckian censorship conjecture

Authors: Rong-Gen Cai, Shao-Jiang Wang

Comments: 6 pages

Subjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)

We propose a refined version of trans-Planckian censorship conjecture (TCC), which could be elaborated from the strong scalar weak gravity conjecture combined with some entropy bounds. In particular, no fine-tuning on the inflation model-building is required in the refined TCC, and it automatically passes the tests from those stringy examples that support the original TCC.

[83]  arXiv:1912.00616 (cross-list from gr-qc) [pdf, other]

Title: Revisiting pre-inflationary universe of family of $α-$attractor in loop quantum cosmology

Authors: M. Shahalam, Mudhahir Al Ajmi, R. Myrzakulov, Anzhong Wang

Comments: 22 pages, 6 caption figures, 4 tables

Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)

In this work, we revisit the dynamics of pre-inflationary universe with a family of $\alpha-$attractor potentials, in the framework of loop quantum cosmology, in which the big bang singularity is generically resolved purely with quantum geometric effects, and replaced by a quantum bounce. At the bounce, the background evolution is divided into two distinct classes, the first is dominated by the kinetic energy of the inflaton field and the second by the potential energy. In both classes, we find the physically viable initial conditions numerically that provide not only the slow-roll inflation, but also sufficient e-folds to be compatible with observations. In the entire range of kinetic energy dominated initial conditions (except some subsets of Models 2 and 4), the background evolution prior to reheating is always split into three different phases: bouncing, transition and slow-roll inflation. In the bouncing phase, the numerical evolution of the scale factor is independent not only of the initial data, but also the inflationary potentials, as long as it is dominated by the kinetic energy, and can be well approximated by an analytical solution, whereas in the potential energy dominated case, such approximated results do not exist. Moreover, we study the phase space analysis for a class of $\alpha-$attractor potentials, and discuss the phase space trajectories for physically viable initial conditions of the inflaton field.

[84]  arXiv:1912.00647 (cross-list from physics.plasm-ph) [pdf]

Title: New insights on prebiotic chemistry from plasma kinetics

Authors: Gaia Micca Longo, Vincenzo Laporta, Savino Longo

Subjects: Plasma Physics (physics.plasm-ph); Earth and Planetary Astrophysics (astro-ph.EP); Atomic Physics (physics.atom-ph)

The famous Miller-Urey experiment, which provides essential information on the prebiotic synthesis of the molecules of life, still has many obscure points. In this paper, we want to suggest a way of possible future progress, which consists in framing the experience of Miller and Urey in the context of the kinetics of ionized gas, or plasma. In this framework, extremely effective and versatile theoretical tools, based on quantum mechanics and chemical kinetics, make it possible to look, in a new way, at the elementary processes that lead to the formation of excited species and ions, at the base of the cascade of subsequent reactions.

[85]  arXiv:1912.00685 (cross-list from gr-qc) [pdf, other]

Title: Relativistic stars in mass-varying massive gravity

Authors: Xue Sun, Shuang-Yong Zhou

Comments: 9 pages, 9 figures

Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE)

Mass-varying massive gravity allows the graviton mass to vary according to different environments. We investigate neutron star and white dwarf solutions in this theory and find that the graviton mass can become very large near the compact stars and settle down quickly to small cosmological values away the stars, similar to that of black holes in the theory. It is found that there exists a tower of compact star solutions where the graviton mass decreases radially to zero non-trivially. We compute the massive graviton effects on the mass-radius relations of the compact stars, and also compare the relative strengths between neutron stars and white dwarfs in constraining the parameter space of mass-varying massive gravity.

[86]  arXiv:1912.00737 (cross-list from cond-mat.stat-mech) [pdf, ps, other]

Title: Brownian motion approach to anomalous rotation of galaxies

Authors: Alexander Jurisch

Comments: 8 pages, 4 figures

Subjects: Statistical Mechanics (cond-mat.stat-mech); Astrophysics of Galaxies (astro-ph.GA)

It has been shown that the weak-interacting limit of the metric-skew-tensor-gravity (MSTG) can explain the anomalous rotation of galaxies without non-baryonic dark matter. We show that MSTG is related to the equilibrium-state of ordinary Brownian motion. We also explore if other stochastic processes can model anomalous rotation. Furthermore, we analyze phase-diagrams that elucidate the condensation of a gravitating cloud towards a Kepler-Newton system and illustrate regions of existence of rotating objects.

[87]  arXiv:1912.00785 (cross-list from gr-qc) [pdf, other]

Title: Gauge Independence of Induced Gravitational Waves

Authors: Keisuke Inomata, Takahiro Terada

Comments: 15 pages, 1 figure

Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)

We study gauge (in)dependence of the gravitational waves (GWs) induced from curvature perturbations. For the GWs produced in a radiation-dominated era, we find that the observable (late-time) GWs in the TT gauge and in the Newtonian gauge are the same in contrast to a claim in the literature. We also mention the interpretation of the gauge dependence of the tensor perturbations which appears in the context of the induced GWs.

[88]  arXiv:1912.00900 (cross-list from gr-qc) [pdf, other]

Title: Violation of Chandrasekhar mass-limit in noncommutative geometry: A strong possible explanation for the super-Chandrasekhar limiting mass white dwarfs

Authors: Surajit Kalita, Banibrata Mukhopadhyay, T. R. Govindarajan

Comments: 9 pages including 1 figure; comments welcome. arXiv admin note: text overlap with arXiv:1908.11206 by other authors

Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)

One of the most celebrated discoveries of twentieth century is the existence of limiting mass of white dwarfs, which is one of the compact objects formed once nuclear burning stops inside the star. On approaching this limiting mass $\sim1.4M_\odot$, called the Chandrasekhar mass-limit, a white dwarf is believed to spark off with an explosion called type Ia supernova, which is considered to be a standard candle. However, observations of several over-luminous, peculiar type Ia supernovae indicate that the Chandrasekhar mass-limit to be significantly larger. By considering noncommutativity of components of position and momentum variables, hence uncertainty in their measurements, at the quantum scales, we show that the mass of white dwarfs could be significantly super-Chandrasekhar and thereby arrive at a new mass-limit $\sim 2.6M_\odot$, explaining a possible origin of over-luminous peculiar type Ia supernovae. The idea of noncommutativity, apart from the Heisenberg's uncertainty principle, is there for quite sometime, without any observational proof however. Our finding offers a plausible astrophysical evidence of noncommutativity, arguing for a possible second standard candle, which has many far reaching implications.

[89]  arXiv:1912.00972 (cross-list from physics.plasm-ph) [pdf, other]

Title: The Magnetorotational Instability Prefers Three Dimensions

Authors: Jeffrey S. Oishi, Geoffrey M. Vasil, Morgan Baxter, Andrew Swan, Keaton J. Burns, Daniel Lecoanet, Benjamin P. Brown

Comments: 15 pages, 5 figures. Proceedings of the Royal Society A, accepted

Subjects: Plasma Physics (physics.plasm-ph); High Energy Astrophysical Phenomena (astro-ph.HE)

The magnetorotational instability (MRI) occurs when a weak magnetic field destabilises a rotating, electrically conducting fluid with inwardly increasing angular velocity. The MRI is essential to astrophysical disk theory where the shear is typically Keplerian. Internal shear layers in stars may also be MRI unstable, and they take a wide range of profiles, including near-critical. We show that the fastest growing modes of an ideal magnetofluid are three-dimensional provided the shear rate, $S$, is near the two-dimensional onset value, $S_c$. For a Keplerian shear, three-dimensional modes are unstable above $S\approx0.10S_c$, and dominate the two-dimensional modes until $S\approx2.05S_{c}$. These three-dimensional modes dominate for shear profiles relevant to stars and at magnetic Prandtl numbers relevant to liquid-metal laboratory experiments. Significant numbers of rapidly growing three-dimensional modes remain well past $2.05S_{c}$. These finding are significant in three ways. First, weakly nonlinear theory suggests that the MRI saturates by pushing the shear rate to its critical value. This can happen for systems, like stars and laboratory experiments, that can rearrange their angular velocity profiles. Second, the non-normal character and large transient growth of MRI modes should be important whenever three-dimensionality exists. Finally, three-dimensional growth suggests direct dynamo action driven from the linear instability.

[90]  arXiv:1912.01000 (cross-list from physics.app-ph) [pdf]

Title: Protective coatings for front surface silver mirrors by atomic layer deposition

Authors: Pavel Bulkin, Sofia Gaiaschi, Patrick Chapon, Dmitri Daineka, Natalya Kundikova

Comments: 19 pages, 7 figures, 1 table, article is based on the regular talk given at The 8th International Conference on Spectroscopic Ellipsometry, May 26-31, 2019, Barcelona

Subjects: Applied Physics (physics.app-ph); Instrumentation and Methods for Astrophysics (astro-ph.IM)

Silver is a metal which provides the highest reflectivity in the very broad wavelength range as well as the lowest polarization splitting. However, it is not very stable chemically and silver mirrors are easily damaged in a corrosive or oxidizing environment, leading first to the drastic drop in reflection followed by the complete disintegration of a silver layer. For this reason aluminum is much more in use. The problem of protection of silver layer is a very important one for number of applications, requiring the front side reflection, such as telescopes mirrors, reflective IR imaging optics, gratings, photovoltaic concentrator mirrors, etc. Atomic layer deposition (ALD) technique using trimethylaluminum (TMA) and water as precursors provides a very efficient way to protect a sensitive surface of silver from a corrosive and oxidizing environment, because ALD coatings can be deposited at rather low temperature. Moreover, ALD layer provides extremely high conformality (even when deposited over high aspect ratio features) and has high integrity, efficiently blocking foreign species diffusion to silver-overcoat interface. In our studies we tested the efficiency of the protection of silver mirrors by ALD-deposited Al2O3 layers against oxygen plasma exposure by correlating the ellipsometric measurements with the absolute reflection measurements and Glow-Discharge Optical Emission Spectroscopy (GD-OES) data. We have found that for optimal protection the thickness of ALD deposited layer should exceed at least 15 nm (about 150 ALD cycles at 150 oC), as thinner layers do not provide reliable protection of silver surface against oxygen plasma. We have also demonstrated that the deposition of 15 nm of a protective ALD-deposited Al2O3 layer does not affect the absolute reflectivity of a silver mirror in a spectral range 300 -2500 nm.

Replacements for Tue, 3 Dec 19

[91]  arXiv:1709.06514 (replaced) [pdf, ps, other]

Title: A study of dust properties in the inner sub-au region of the Herbig Ae star HD 169142 with VLTI/PIONIER

Authors: L. Chen, A. Kospal, P. Abraham, A. Kreplin, A. Matter, G. Weigelt

Comments: 13 pages, 9 figures

Journal-ref: A&A 609, A45 (2018)

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)

[92]  arXiv:1712.00370 (replaced) [pdf, other]

Title: Implications of dark matter cascade decay from DAMPE, HESS, Fermi-LAT and AMS02 data

Authors: Yu Gao, Yin-Zhe Ma

Comments: 8 pages, 1 table, 4 figures

Journal-ref: MNRAS 491, 965-971 (2020)

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)

[93]  arXiv:1806.06716 (replaced) [pdf, other]

Title: Theory of chemical evolution of molecule compositions in the universe, in the Miller-Urey experiment and the mass distribution of interstellar and intergalactic molecules

Authors: Stuart A. Kauffman, David P. Jelenfi, Gabor Vattay

Journal-ref: Journal of Theoretical Biology 2019

Subjects: Populations and Evolution (q-bio.PE); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Biological Physics (physics.bio-ph)

[94]  arXiv:1809.04408 (replaced) [pdf, ps, other]

Title: Gravitational instability caused by the weight of heat

Authors: Zacharias Roupas

Comments: Typos corrected in last update

Journal-ref: Symmetry 2019, 11(12), 1435

Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); Statistical Mechanics (cond-mat.stat-mech); High Energy Physics - Theory (hep-th)

[95]  arXiv:1812.03901 (replaced) [pdf, ps, other]

Title: Acceleration and Escape Processes of High-energy Particles in Turbulence inside Hot Accretion Flows

Authors: Shigeo S. Kimura, Kengo Tomida, Kohta Murase

Comments: 17 pages, 16 figures, Figure 4 is corrected, conclusions are unchanged, published in MNRAS

Journal-ref: Mon.Not.Roy.Astron.Soc. 485 (2019) 163

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

[96]  arXiv:1903.07281 (replaced) [pdf, other]

Title: More about Q-ball with elliptical orbit

Authors: Fuminori Hasegawa, Jeong-Pyong Hong, Motoo Suzuki

Comments: 10 pages, 14 figures

Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

[97]  arXiv:1903.09046 (replaced) [pdf, other]

Title: The Ly$α$ Luminosity Function and Cosmic Reionization at $z \sim$ 7.0: a Tale of Two LAGER Fields

Authors: Weida Hu, Junxian Wang, Zhen-Ya Zheng, Sangeeta Malhotra, James E. Rhoads, Leopoldo Infante, L. Felipe Barrientos, Huan Yang, Chunyan Jiang, Wenyong Kang, Lucia A. Perez, Isak Wold, Pascale Hibon, Linhua Jiang, Ali Ahmad Khostovan, Francisco Valdes, Alistair R. Walker, Gaspar Galaz, Alicia Coughlin, Santosh Harish, Xu Kong, John Pharo, XianZhong Zheng

Comments: 23 pages, 11 figures, 2 tables, accepted for publication in ApJ

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[98]  arXiv:1904.08946 (replaced) [pdf, ps, other]

Title: Rapid Luminosity Decline and Subsequent Reformation of the Innermost Dust Distribution in the Changing-look AGN Mrk 590

Authors: Mitsuru Kokubo (Tohoku University), Takeo Minezaki (The University of Tokyo)

Comments: 21 pages, 8 figures, 4 tables, accepted for publication in MNRAS 2019 November 29

Subjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)

[99]  arXiv:1904.11009 (replaced) [pdf, other]

Title: Evidence for Late-stage Eruptive Mass-loss in the Progenitor to SN2018gep, a Broad-lined Ic Supernova: Pre-explosion Emission and a Rapidly Rising Luminous Transient

Authors: Anna Y. Q. Ho (Caltech), Daniel A. Goldstein, Steve Schulze, David K. Khatami, Daniel A. Perley, Mattias Ergon, Avishay Gal-Yam, Alessandra Corsi, Igor Andreoni, Cristina Barbarino, Eric C. Bellm, Nadia Blagorodnova, Joe S. Bright, Eric Burns, S. Bradley Cenko, Virginia Cunningham, Kishalay De, Richard Dekany, Alison Dugas, Rob P. Fender, Claes Fransson, Christoffer Fremling, Adam Goldstein, Matthew J. Graham, David Hale, Assaf Horesh, Tiara Hung, Mansi M. Kasliwal, N. Paul M. Kuin, Shri R. Kulkarni, Thomas Kupfer, Ragnhild Lunnan, Frank J. Masci, Chow-Choong Ngeow, Peter E. Nugent, Eran O. Ofek, Maria T. Patterson, Glen Petitpas, Ben Rusholme, Hanna Sai, Itai Sfaradi, David L. Shupe, Jesper Sollerman, Maayane T. Soumagnac, Yutaro Tachibana, Francesco Taddia, Richard Walters, Xiaofeng Wang, et al. (2 additional authors not shown)

Comments: Accepted to ApJ on 1 Oct 2019. In this version, we made minor corrections and removed extraneous references

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

[100]  arXiv:1905.05752 (replaced) [pdf, ps, other]

Title: From massive spirals to dwarf irregulars: a new set of tight scaling relations for cold gas and stars driven by disc gravitational instability

Authors: Alessandro B. Romeo

Comments: MNRAS, in press. Changed from letter to paper format, and revised significantly

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Plasma Physics (physics.plasm-ph)

[101]  arXiv:1905.09781 (replaced) [pdf, other]

Title: Model-independent determination of $H_0$ and $Ω_{K0}$ from strong lensing and type Ia supernovae

Authors: Thomas Collett, Francesco Montanari, Syksy Rasanen

Comments: 7 pages, 1 figure. V2. Added clarifications. Published version

Journal-ref: Phys. Rev. Lett. 123, 231101 (2019)

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)

[102]  arXiv:1906.09554 (replaced) [pdf, other]

Title: Swift UVOT Grism Observations of Nearby Type Ia Supernovae -- II. Probing the Progenitor Metallicity of SNe Ia with Ultraviolet Spectra

Authors: Y.-C. Pan, R. J. Foley, D. O. Jones, A. V. Filippenko, N. P. M. Kuin

Comments: Accepted for publication in MNRAS

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)

[103]  arXiv:1907.00989 (replaced) [pdf, other]

Title: Beyond two-point statistics: using the minimum spanning tree as a tool for cosmology

Authors: Krishna Naidoo, Lorne Whiteway, Elena Massara, Davide Gualdi, Ofer Lahav, Matteo Viel, Héctor Gil-Marín, Andreu Font-Ribera

Comments: 19 pages, 15 figures (including 2 page appendix with 2 figures), text based edits to match version published in MNRAS

Journal-ref: Monthly Notices of the Royal Astronomical Society, Volume 491, Issue 2, January 2020, Pages 1709-1726

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

[104]  arXiv:1907.02999 (replaced) [pdf, other]

Title: A Self-consistent Framework for Multiline Modeling in Line Intensity Mapping Experiments

Authors: Guochao Sun, Brandon S. Hensley, Tzu-Ching Chang, Olivier Doré, Paolo Serra

Comments: Accepted for publication in ApJ

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[105]  arXiv:1907.07634 (replaced) [pdf, ps, other]

Title: CubeSats for Astronomy and Astrophysics

Authors: Ewan S. Douglas, Kerri L. Cahoy, Mary Knapp, Rachel E. Morgan

Comments: 6 pages, 0 figures. APC white paper submitted to the Astro2020 Decadal Survey with minor typographical edits

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)

[106]  arXiv:1907.10112 (replaced) [pdf, other]

Title: Einstein--scalar--Gauss--Bonnet black holes: Analytical approximation for the metric and applications to calculations of shadows

Authors: Roman A. Konoplya, Thomas Pappas, Alexander Zhidenko

Comments: 20 pages, 9 figures, 1 ancillary Mathematica(R) notebook

Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Theory (hep-th)

[107]  arXiv:1907.10608 (replaced) [pdf, other]

Title: A 40-billion solar mass black hole in the extreme core of Holm 15A, the central galaxy of Abell 85

Authors: K. Mehrgan, J. Thomas, R. Saglia, X. Mazzalay, P. Erwin, R. Bender, M. Kluge, M. Fabricius

Comments: 25 pages, 20 figures, accepted for publication in the Astrophysical Journal

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[108]  arXiv:1907.13108 (replaced) [pdf, ps, other]

Title: Inflationary perturbation spectra at next-to-leading slow-roll order in effective field theory of inflation

Authors: Guang-Hua Ding, Jin Qiao, Qiang Wu, Tao Zhu, Anzhong Wang

Comments: 11 pages. arXiv admin note: text overlap with arXiv:1811.03216, arXiv:1707.08020; version published in Eur. Phys. J. C

Journal-ref: Eur. Phys. J. C 79, 976 (2019)

Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)

[109]  arXiv:1908.01107 (replaced) [pdf, other]

Title: A unified binary neutron star merger magnetar model for the Chandra X-ray transients CDF-S XT1 and XT2

Authors: Hui Sun, Ye Li, Binbin Zhang, Bing Zhang, Franz E. Bauer, Yongquan Xue, Weimin Yuan

Comments: 8 pages, 5 figures, accepted for publication in ApJ

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

[110]  arXiv:1908.01391 (replaced) [pdf, other]

Title: Cosmological constraints in extended parameter space from the Planck 2018 Legacy release

Authors: Eleonora Di Valentino, Alessandro Melchiorri, Joseph Silk

Comments: 9 pages, 3 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)

[111]  arXiv:1908.04624 (replaced) [pdf, other]

Title: Non-Equilibrium Spectrum Formation Affecting Solar Irradiance

Authors: Robert J. Rutten

Comments: Editor's Choice lead article of Solar Physics Topical Selection "Irradiance Variations of the Sun and Sun-like Stars". The arXiv pdf is better for e-reading because the publisher destroyed citation links and refused repair

Journal-ref: Solar Physics (2019) 294,165

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

[112]  arXiv:1908.08421 (replaced) [pdf, ps, other]

Title: Multi-messenger tests of cosmic-ray acceleration in radiatively inefficient accretion flows

Authors: Shigeo S. Kimura, Kohta Murase, Peter Mészáros

Comments: 15 pages, 6 figures, 3 tables, Typos in Figure 3 are corrected, conclusions are unchanged

Journal-ref: Phys. Rev. D 100, 083014 (2019)

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)

[113]  arXiv:1908.09409 (replaced) [pdf, ps, other]

Title: Electric and magnetic axion quark nuggets, their stability and their detection

Authors: O. Santillan, M. Sempe

Comments: 21 pages, no figures. Typos corrected and some explanations added

Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE)

[114]  arXiv:1909.07034 (replaced) [pdf, other]

Title: Discrimination of heavy elements originating from Pop III stars in z = 3 intergalactic medium

Authors: Takanobu Kirihara, Kenji Hasegawa, Masayuki Umemura, Masao Mori, Tomoaki Ishiyama

Comments: 10 pages, 8 figures, accepted for publication in MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[115]  arXiv:1909.12857 (replaced) [pdf, other]

Title: Implications on the origin of cosmic rays in light of 10 TV spectral softenings

Authors: Chuan Yue, Peng-Xiong Ma, Qiang Yuan, Yi-Zhong Fan, Zhan-Fang Chen, Ming-Yang Cui, Hao-Ting Dai, Tie-Kuang Dong, Xiaoyuan Huang, Wei Jiang, Shi-Jun Lei, Xiang Li, Cheng-Ming Liu, Hao Liu, Yang Liu, Chuan-Ning Luo, Xu Pan, Wen-Xi Peng, Rui Qiao, Yi-Feng Wei, Li-Bo Wu, Zhi-Hui Xu, Zun-Lei Xu, Guan-Wen Yuan, Jing-Jing Zang, Ya-Peng Zhang, Yong-Jie Zhang, Yun-Long Zhang

Comments: 8 pages, 3 figures and 3 tables; accepted for publication in Frontiers of Physics

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

[116]  arXiv:1910.04776 (replaced) [pdf, other]

Title: Maximally accreting supermassive stars: a fundamental limit imposed by hydrostatic equilibrium

Authors: L. Haemmerlé, G. Meynet, L. Mayer, R. S. Klessen, T. E. Woods, A. Heger

Comments: 5 pages, 3 figures

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)

[117]  arXiv:1910.13277 (replaced) [pdf, ps, other]

Title: Upscattered Cocoon Emission in Short Gamma-ray Bursts as High-energy Gamma-ray Counterparts to Gravitational Waves

Authors: Shigeo S. Kimura, Kohta Murase, Kunihito Ioka, Shota Kisaka, Ke Fang, Peter Mészáros

Comments: 8pages, 3 figures, accepted for publication in ApJL

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)

[118]  arXiv:1911.01233 (replaced) [pdf, ps, other]

Title: Asymptotic behavior of a matter filled universe with exotic topology

Authors: Puskar Mondal

Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Mathematical Physics (math-ph)

[119]  arXiv:1911.03606 (replaced) [pdf, ps, other]

Title: Correspondence of cosmology from non-extensive thermodynamics with fluids of generalized equation of state

Authors: Shin'ichi Nojiri, Sergei D. Odintsov, Emmanuel N. Saridakis, R. Myrzakulov

Comments: 7 pages, version published in Nucl.Phys.B

Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)

[120]  arXiv:1911.04495 (replaced) [pdf, other]

Title: Formation and merging of Mass Gap Black Holes in Gravitational Wave Merger Events from Wide Hierarchical Quadruple Systems

Authors: Mohammadtaher Safarzadeh, Adrian S. Hamers, Abraham Loeb, Edo Berger

Comments: Accepted for publication at ApJ Letters

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

[121]  arXiv:1911.07832 (replaced) [pdf, other]

Title: Angular Correlation Function Estimators Accounting for Contamination from Probabilistic Distance Measurements

Authors: Humna Awan, Eric Gawiser

Comments: 23 pages and 4 appendices (17 pages). 17 figures. Submitted to ApJ, with this version revised further in response to comments from the referee, with an expanded photo-z model (Section 5.3)

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

[122]  arXiv:1911.09707 (replaced) [pdf, other]

Title: High-resolution Photo-excitation Measurements Exacerbate the Long-standing Fe XVII Emission Problem

Authors: Steffen Kühn (1, 2), Chintan Shah (1, 3), José R. Crespo López-Urrutia (1), Keisuke Fujii (4), René Steinbrügge (5), Jakob Stierhof (6), Moto Togawa (1), Zoltán Harman (1), Natalia S. Oreshkina (1), Charles Cheung (7), Mikhail G. Kozlov (8, 9), Sergey G. Porsev (8, 7), Marianna S. Safronova (7, 10), Julian C. Berengut (11, 1), Michael Rosner (1), Matthias Bissinger (12, 6), Ralf Ballhausen (6), Natalie Hell (13), SungNam Park (14), Moses Chung (14), Moritz Hoesch (5), Jörn Seltmann (5), Andrey S. Surzhykov (15, 16), Vladimir A. Yerokhin (17), Jörn Wilms (6), F. Scott Porter (3), Thomas Stöhlker (18, 19, 20), Christoph H. Keitel (1), Thomas Pfeifer (1), Gregory V. Brown (13), Maurice A. Leutenegger (3), Sven Bernitt (1, 18, 19, 20) ((1) Max-Planck-Institut für Kernphysik, Heidelberg, Germany, (2) Heidelberg Graduate School of Fundamental Physics, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany, (3) NASA/Goddard Space Flight Center, Greenbelt, USA, (4) Department of Mechanical Engineering and Science, Graduate School of Engineering, Kyoto University, Japan, (5) Deutsches Elektronen-Sychrotron DESY, Hamburg, Germany, (6) Dr. Karl Remeis-Sternwarte, Bamberg, Germany, (7) Department of Physics and Astronomy, University of Delaware, Newark, USA, (8) Petersburg Nuclear Physics Institute of NRC "Kurchatov Institute", Russia (9) St. Petersburg Electrotechnical University "LETI", St. Petersburg, Russia, (10) Joint Quantum Institute, National Institute of Standards and Technology and the University of Maryland, Gaithersburg, USA, (11) School of Physics, University of New South Wales, Sydney, Australia, (12) Erlangen Centre for Astroparticle Physics (ECAP), Erlangen, Germany, (13) Lawrence Livermore National Laboratory, Livermore, USA, (14) Ulsan National Institute of Science and Technology, Ulsan, South Korea, (15) Physikalisch-Technische Bundesanstalt, Braunschweig, Germany, (16) Braunschweig University of Technology, Braunschweig, Germany, (17) Peter the Great St.Petersburg Polytechnic University, St. Petersburg, Russia, (18) Institut für Optik und Quantenelektronik, Friedrich-Schiller-Universität Jena, Jena, Germany, (19) Helmholtz-Institut Jena, Jena, Germany, (20) GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany)

Comments: Main text (6 pages, 3 figures), Supplmentary Material (7 pages, 3 figure), submitted to PRL

Subjects: Atomic Physics (physics.atom-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR); Plasma Physics (physics.plasm-ph)

[123]  arXiv:1911.09850 (replaced) [pdf, other]

Title: Signals of Axion Like Dark Matter in Time Dependent Polarization of Light

Authors: So Chigusa, Takeo Moroi, Kazunori Nakayama

Comments: 18 pages, 2 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)

[124]  arXiv:1911.10609 (replaced) [pdf, other]

Title: Tension of the $E_G$ statistic and RSD data with Planck/$Λ$CDM and implications for weakening gravity

Authors: F. Skara, L. Perivolaropoulos

Comments: 20 pages, 7 Figures. References added. Comments added in the `Conclusion' section on the effects of lensing on the $E_G$ data. The data and the Mathematica data analysis files may be downloaded from this http URL

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)

[125]  arXiv:1911.11701 (replaced) [pdf, other]

Title: Shot noise in multi-tracer constraints on $f_\text{NL}$ and relativistic projections: Power Spectrum

Authors: Dimitry Ginzburg, Vincent Desjacques

Comments: Comments are welcomed

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

[126]  arXiv:1911.13113 (replaced) [pdf, ps, other]

Title: Photometric rotation periods for 107 M dwarfs from the APACHE survey

Authors: P. Giacobbe, M. Benedetto, M. Damasso, A. Sozzetti, J.M. Christille, M.G. Lattanzi, P. Calcidese, A. Carbognani, D. Barbato, M. Pinamonti, E. Poggio, A. F. Lanza, A. Bernagozzi, D. Cenadelli, L. Lanteri, E. Bertolini

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

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