Astrophysics

New submissions

• New submissions
• Cross-lists
• Replacements

New submissions for Fri, 21 Feb 20

[1]  arXiv:2002.08366 [pdf, other]

Title: Giant planet swaps during close stellar encounters

Authors: Yi-Han Wang, Rosalba Perna, Nathan W. C. Leigh

Comments: Accepted to ApJ Letters

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

The discovery of planetary systems outside of the solar system has challenged some of the tenets of planetary formation. Among the difficult-to-explain observations, are systems with a giant planet orbiting a very-low mass star, such as the recently discovered GJ~3512b planetary system, where a Jupiter-like planet orbits an $M$-star in a tight and eccentric orbit. Systems such as this one are not predicted by the core accretion theory of planet formation. Here we suggest a novel mechanism, in which the giant planet is born around a more typical Sun-like star ($M_{*,1}$), but is subsequently exchanged during a dynamical interaction with a flyby low-mass star ($M_{*,2}$). We perform state-of-the-art $N$-body simulations with $M_{*,1}=1M_\odot$ and $M_{*,2}=0.1M_\odot$ to study the statistical outcomes of this interaction, and show that exchanges result in high eccentricities for the new orbit around the low-mass star, while about half of the outcomes result in tighter orbits than the planet had around its birth star. We numerically compute the cross section for planet exchange, and show that an upper limit for the probability per planetary system to have undergone such an event is $\Gamma\sim 4.4(M_{\rm c}/100M_\odot)^{-2}(a_{\rm p}/{\rm AU}) (\sigma/1\,{\rm km}\,{\rm s}^{-1})^{5}$Gyr$^{-1}$, where $a_{\rm p}$ is the planet semi-major axis around the birth star, $\sigma$ the velocity dispersion of the star cluster, and $M_{\rm c}$ the total mass of the star cluster. Hence these planet exchanges could be relatively common for stars born in open clusters and groups, should already be observed in the exoplanet database, and provide new avenues to create unexpected planetary architectures.

[2]  arXiv:2002.08371 [pdf, other]

Title: Measuring the Heating and Cooling of the Interstellar Medium at High redshift: PAH and [C II] Observations of the Same Star Forming Galaxies at z~2

Authors: Jed McKinney, Alexandra Pope, Lee Armus, Ranga-Ram Chary, Tanio Diaz-Santos, Mark E. Dickinson, Allison Kirkpatrick

Comments: Accepted to The Astrophysical Journal, 22 pages, 11 figures

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

Star formation depends critically on cooling mechanisms in the interstellar medium (ISM); however, thermal properties of gas in galaxies at the peak epoch of star formation (z ~ 2) remain poorly understood. A limiting factor in understanding the multiphase ISM is the lack of multiple tracers detected in the same galaxies, such as Polycyclic Aromatic Hydrocarbon (PAH) emission, a tracer of a critical photoelectric heating mechanism in interstellar gas, and [C II] 158{\mu}m fine-structure emission, a principal coolant. We present ALMA Band 9 observations targeting [C II] in six z ~ 2 star-forming galaxies with strong Spitzer IRS detections of PAH emission. All six galaxies are detected in dust continuum and marginally resolved. We compare the properties of PAH and [C II] emission, and constrain their relationship as a function of total infrared luminosity (LIR) and IR surface density. [C II] emission is detected in one galaxy at high signal-to-noise (34{\sigma}), and we place a secure upper limit on a second source. The rest of our sample are not detected in [C II] likely due to redshift uncertainties and narrow ALMA bandpass windows. Our results are consistent with the deficit in [C II]/LIR and PAH/LIR observed in the literature. However, the ratio of [C II] to PAH emission at z ~ 2 is possibly much lower than what is observed in nearby dusty star-forming galaxies. This could be the result of enhanced cooling via [O I] at high-z, hotter gas and dust temperatures, and/or a reduction in the photoelectric efficiency, in which the coupling between interstellar radiation and gas heating is diminished.

[3]  arXiv:2002.08372 [pdf, other]

Title: Linking the formation and fate of exo-Kuiper belts within solar system analogues

Authors: Dimitri Veras, Katja Reichert, Francesco Flammini Dotti, Maxwell X. Cai, Alexander J. Mustill, Andrew Shannon, Catriona H. McDonald, Simon Portegies Zwart, M.B.N. Kouwenhoven, Rainer Spurzem

Comments: Accepted for publication in MNRAS

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

Escalating observations of exo-minor planets and their destroyed remnants both passing through the solar system and within white dwarf planetary systems motivate an understanding of the orbital history and fate of exo-Kuiper belts and planetesimal discs. Here we explore how the structure of a 40-1000 au annulus of planetesimals orbiting inside of a solar system analogue that is itself initially embedded within a stellar cluster environment varies as the star evolves through all of its stellar phases. We attempt this computationally challenging link in four parts: (1) by performing stellar cluster simulations lasting 100 Myr, (2) by making assumptions about the subsequent quiescent 11 Gyr main-sequence evolution, (3) by performing simulations throughout the giant branch phases of evolution, and (4) by making assumptions about the belt's evolution during the white dwarf phase. Throughout these stages, we estimate the planetesimals' gravitational responses to analogues of the four solar system giant planets, as well as to collisional grinding, Galactic tides, stellar flybys, and stellar radiation. We find that the imprint of stellar cluster dynamics on the architecture of $\gtrsim 100$ km-sized exo-Kuiper belt planetesimals is retained throughout all phases of stellar evolution unless violent gravitational instabilities are triggered either (1) amongst the giant planets, or (2) due to a close ($\ll 10^3$ au) stellar flyby. In the absence of these instabilities, these minor planets simply double their semimajor axis while retaining their primordial post-cluster eccentricity and inclination distributions, with implications for the free-floating planetesimal population and metal-polluted white dwarfs.

[4]  arXiv:2002.08373 [pdf, other]

Title: A search for the lenses in the Herschel Bright Sources (HerBS) Sample

Authors: Tom J. L. C. Bakx, Stephen Eales, Aristeidis Amvrosiadis

Comments: 18 pages, 15 figures, Accepted for MNRAS, 12 additional figures can be found in ArXiv source

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

Verifying that sub-mm galaxies (SMGs) are gravitationally lensed requires time-expensive observations with over-subscribed high-resolution observatories. Here, we aim to strengthen the evidence of gravitational lensing within the Herschel Bright Sources (HerBS) by cross-comparing their positions to optical (SDSS) and near-infrared (VIKING) surveys, in order to search for the foreground lensing galaxy candidates. Resolved observations of the brightest HerBS sources have already shown that most are lensed, and a galaxy evolution model predicts that $\sim$76% of the total HerBS sources are lensed, although with the SDSS survey we are only able to identify the likely foreground lenses for 25% of the sources. With the near-infrared VIKING survey, however, we are able to identify the likely foreground lenses for 57% of the sources, and we estimate that 82% of the HerBS sources have lenses on the VIKING images even if we cannot identify the lens in every case. We find that the angular offsets between lens and Herschel source are larger than that expected if the lensing is done by individual galaxies. We also find that the fraction of HerBS sources that are lensed falls with decreasing 500-micron flux density, which is expected from the galaxy evolution model. Finally, we apply our statistical VIKING cross-identification to the entire Herschel-ATLAS catalogue, where we also find that the number of lensed sources falls with decreasing 500-micron flux density.

[5]  arXiv:2002.08374 [pdf, other]

Title: Modeling the orbital motion of Sgr A*'s near-infrared flares

Authors: The GRAVITY Collaboration: M. Bauböck, J. Dexter, R. Abuter, A. Amorim, J.P. Berger, H. Bonnet, W. Brandner, Y. Clénet, V. Coudé du Foresto, P.T. de Zeeuw, G. Duvert, A. Eckart, F. Eisenhauer, N.M. Förster Schreiber, F. Gao, P. Garcia, E. Gendron, R. Genzel, O. Gerhard, S. Gillessen, M. Habibi, X. Haubois, T. Henning, S. Hippler, M. Horrobin, A. Jiménez-Rosales, L. Jocou, P. Kervella, S. Lacour, V. Lapeyrère, J.-B. Le Bouquin, P. Léna, T. Ott, T. Paumard, K. Perraut, G. Perrin, O. Pfuhl, S. Rabien, G. Rodriguez Coira, G. Rousset, S. Scheithauer, J. Stadler, A. Sternberg, O. Straub, C. Straubmeier, E. Sturm, L.J. Tacconi, F. Vincent, S. von Fellenberg, I. Waisberg, F. Widmann, E. Wieprecht, E. Wiezorrek, J. Woillez, S. Yazici

Comments: Accepted in A&A

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

Infrared observations of Sgr A* probe the region close to the event horizon of the black hole at the Galactic center. These observations can constrain the properties of low-luminosity accretion as well as that of the black hole itself. The GRAVITY instrument at the ESO VLTI has recently detected continuous circular relativistic motion during infrared flares which has been interpreted as orbital motion near the event horizon. Here we analyze the astrometric data from these flares, taking into account the effects of out-of-plane motion and orbital shear of material near the event horizon of the black hole. We have developed a new code to predict astrometric motion and flux variability from compact emission regions following particle orbits. Our code combines semi-analytic calculations of timelike geodesics that allow for out-of-plane or elliptical motions with ray tracing of photon trajectories to compute time-dependent images and light curves. We apply our code to the three flares observed with GRAVITY in 2018. We show that all flares are consistent with a hotspot orbiting at R$\sim$9 gravitational radii with an inclination of $i\sim140^\circ$. The emitting region must be compact and less than $\sim5$ gravitational radii in diameter. We place a further limit on the out-of-plane motion during the flare.

[6]  arXiv:2002.08377 [pdf, other]

Title: Time Dependent Radiation Hydrodynamics on a Moving Mesh

Authors: Philip Chang, Shane W. Davis, Yan-Fei Jiang

Comments: 13 pages, 8 figures, submitted to MNRAS

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

We describe the structure and implementation of a radiation hydrodynamic solver for MANGA, the moving-mesh hydrodynamics module of the large-scale parallel code, Charm N-body GrAvity solver (ChaNGa). We solve the equations of time dependent radiative transfer using a reduced speed of light approximation following the algorithm of Jiang et al (2014). By writing the radiative transfer equations as a generalized conservation equation, we solve the transport part of these equations on an unstructured Voronoi mesh. We then solve the source part of the radiative transfer equations following Jiang et al (2014) using an implicit solver, and couple this to the hydrodynamic equations. The use of an implicit solver ensure reliable convergence and preserves the conservation properties of these equations even in situations where the source terms are stiff due to the small coupling timescales between radiation and matter. We present the results of a limited number of test cases (energy conservation, momentum conservation, dynamic diffusion, linear waves, crossing beams, and multiple shadows) to show convergence with analytic results and numerical stability. We also show that it produces qualitatively the correct results in the presence of multiple sources in the optically thin case.

[7]  arXiv:2002.08378 [pdf, other]

Title: HOLISMOKES -- I. Highly Optimised Lensing Investigations of Supernovae, Microlensing Objects, and Kinematics of Ellipticals and Spirals

Authors: S. H. Suyu, S. Huber, R. Cañameras, S. Schuldt, S. Taubenberger, A. Yıldırım, V. Bonvin, J. H. H. Chan, F. Courbin, M. Kromer, U. Nöbauer, S. A. Sim, D. Sluse

Comments: 9 pages, 8 figures, submitted to A&A

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

We present the HOLISMOKES project on strong gravitational lensing of supernovae (SNe) as a probe of SN physics and cosmology. We investigate the effects of microlensing on early-phase SN Ia spectra, and find that within 10 rest-frame days after SN explosion, distortions of SN Ia spectra due to microlensing are typically negligible (<1% distortion within the 68% credible region, and ~10% distortion within the 95% credible region). This shows great prospects of using lensed SNe Ia to obtain intrinsic early-phase SN spectra for deciphering SN Ia progenitors. As a demonstration of the usefulness of lensed SNe Ia for cosmology, we simulate a sample of mock lensed SN Ia systems that are expected to have accurate and precise time-delay measurements in the era of the Legacy Survey of Space and Time (LSST). Adopting realistic yet conservative uncertainties on their time-delay distances and lens angular diameter distances (of 6.6% and 5%, respectively), we find that a sample of 20 lensed SNe Ia would allow a constraint on the Hubble constant ($H_0$) with 1.3% uncertainty in the flat $\Lambda$CDM cosmology. We find a similar constraint on $H_0$ in an open $\Lambda$CDM cosmology, while the constraint degrades to 3% in a flat wCDM cosmology. We anticipate lensed SNe to be an independent and powerful probe of SN physics and cosmology in the upcoming LSST era.

[8]  arXiv:2002.08379 [pdf, other]

Title: Detection of Na, K, and H$α$ absorption in the atmosphere of WASP-52b using ESPRESSO

Authors: G. Chen, N. Casasayas-Barris, E. Palle, F. Yan, M. Stangret, H. M. Cegla, R. Allart, C. Lovis

Comments: 12 pages, 11 figures, accepted for publication in A&A on Feb 18, 2020

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

WASP-52b is a low density hot Jupiter orbiting a moderately active K2V star. Previous low-resolution studies have revealed a cloudy atmosphere and found atomic Na above the cloud deck. Here we report the detection of excess absorption at the Na doublet, the H$\alpha$ line, and the K D$_1$ line. We derived a high-resolution transmission spectrum based on three transits of WASP-52b, observed with the ultra stable, high-resolution spectrograph ESPRESSO at the VLT. We measure a line contrast of $1.09\pm 0.16$% for Na D$_1$, $1.31\pm 0.13$% for Na D$_2$, $0.86\pm 0.13$% for H$\alpha$, and $0.46\pm 0.13$% for K D$_1$, with a line FWHM range of 11-22 km s$^{-1}$. We also find that the velocity shift of these detected lines during the transit is consistent with the planet orbital motion, thus confirming their planetary origin. We do not observe any significant net blueshift or redshift that can be attributed to planetary winds. We use activity indicator lines as control but find no excess absorption. However, we do notice signatures arising from the Center-to-Limb variation (CLV) and the Rossiter-McLaughlin (RM) effect at these control lines. This highlights the importance of the CLV+RM correction in correctly deriving the transmission spectrum, which, if not corrected, could resemble or cancel out planetary absorption in certain cases. WASP-52b is the second non-ultra-hot Jupiter to show excess H$\alpha$ absorption, after HD 189733b. Future observations targeting non-ultra-hot Jupiters that show H$\alpha$ could help reveal the relation between stellar activity and the heating processes in the planetary upper atmosphere.

[9]  arXiv:2002.08380 [pdf, ps, other]

Title: The building blocks of the Milky Way halo using APOGEE and Gaia -- or -- Is the Galaxy a typical galaxy?

Authors: Ricardo P. Schiavon, J. Ted Mackereth, Joel Pfeffer, Rob A. Crain, Jo Bovy

Comments: To Appear in "Star Clusters: From the Milky Way to the Early Universe ", Proceedings of IAU Symposium No. 351, 2019, A. Bragaglia, M.B. Davies, A. Sills & E. Vesperini, eds. Four pages, no figures

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

We summarise recent results from analysis of APOGEE/Gaia data for stellar populations in the Galactic halo, disk, and bulge, leading to constraints on the contribution of dwarf galaxies and globular clusters to the stellar content of the Milky Way halo. Interpretation of the extant data in light of cosmological numerical simulations suggests that the Milky Way has been subject to an unusually intense accretion history at z >~ 1.5.

[10]  arXiv:2002.08381 [pdf, ps, other]

Title: The Dark Planets of the WASP-47 Planetary System

Authors: Stephen R. Kane, Tara Fetherolf, Michelle L. Hill

Comments: 13 pages, 6 figures, 2 tables, accepted for publication in the Astronomical Journal

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

Exoplanet discoveries have demonstrated a vast range of planetary system architectures. The demographic of compact planetary systems are especially interesting from the perspective of planetary formation and the evolution of orbital dynamics. Another interesting demographic is that of giant planets in eccentric orbits, since these planets have likely had a dynamical history involving planet-planet scattering events. The WASP-47 system is particularly fascinating since it combines these two demographics, having both compact planetary orbits and a giant planet on an eccentric orbit within the system Habitable Zone. Here we provide an analysis of the WASP-47 system from the perspective of atmospheric detection and characterization. We discuss the system architecture and the potential for additional long-period planets. We simulate expected phase variations as a function of planet orbital phase for the system due to the combined effect of the planets. We present analysis of precision photometry of WASP-47 from the K2 mission, phased on each of the planets. The analysis rules out the detection of phase signatures for the two inner-most planets, enabling constraints upon their albedos and atmospheric properties. Our study concludes that WASP-47b is an example of a "dark" planet with a tentative geometric albedo of 0.016 and a 1$\sigma$ upper limit of 0.17. The WASP-47e data are consistent with a broad range of albedos, but also show early evidence of having a relatively low albedo. The growing number of dark, short-period giant planets provide the framework of an ideal sample for studying low albedo dependence on atmospheric composition.

[11]  arXiv:2002.08386 [pdf, other]

Title: Observational signatures of disk and jet misalignment in images of accreting black holes

Authors: Koushik Chatterjee, Ziri Younsi, Matthew Liska, Alexander Tchekhovskoy, Sera Markoff, Doosoo Yoon, David van Eijnatten, Casper Hesp, Adam Ingram, Michiel van der Klis

Comments: 17 pages, 19 figures, submitted to MNRAS, for YouTube playlist see this https URL

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

Black hole accretion is one of nature's most efficient energy extraction processes. When gas falls in, a significant fraction of its gravitational binding energy is either converted into radiation or flows outwards in the form of black hole-driven jets and disk-driven winds. Recently, the Event Horizon Telescope (EHT), an Earth-size sub-millimetre radio interferometer, captured the first images of M87's black hole (or M87*). These images were analysed and interpreted using general-relativistic magnetohydrodynamics (GRMHD) models of accretion disks with rotation axes aligned with the black hole spin axis. However, since infalling gas is often insensitive to the black hole spin direction, misalignment between accretion disk and black hole spin may be a common occurrence in nature. In this work, we use the general-relativistic radiative transfer (GRRT) code \texttt{BHOSS} to calculate the first synthetic radio images of (highly) tilted disk/jet models generated by our GPU-accelerated GRMHD code \texttt{HAMR}. While the tilt does not have a noticeable effect on the system dynamics beyond a few tens of gravitational radii from the black hole, the warping of the disk and jet can imprint observable signatures in EHT images on smaller scales. Comparing the images from our GRMHD models to the 43 GHz and 230 GHz EHT images of M87, we find that M87 may feature a tilted disk/jet system. Further, tilted disks and jets display significant time variability in the 230 GHz flux that can be further tested by longer-duration EHT observations of M87.

[12]  arXiv:2002.08390 [pdf, other]

Title: APOGEE Net: Improving the derived spectral parameters for young stars through deep learning

Authors: Richard Olney, Marina Kounkel, Chad Schillinger, Matthew T. Scoggins, Yichuan Yin, Erin Howard, K. R. Covey, Brian Hutchinson, Keivan G. Stassun

Comments: Accepted to AJ, 23 pages, 12 figures

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

Machine learning allows efficient extraction of physical properties from stellar spectra that have been obtained by large surveys. The viability of ML approaches has been demonstrated for spectra covering a variety of wavelengths and spectral resolutions, but most often for main sequence or evolved stars, where reliable synthetic spectra provide labels and data for training. Spectral models of young stellar objects (YSOs) and low mass main sequence (MS) stars are less well-matched to their empirical counterparts, however, posing barriers to previous approaches to classify spectra of such stars. In this work we generate labels for YSOs and low mass MS stars through their photometry. We then use these labels to train a deep convolutional neural network to predict log g, Teff, and Fe/H for stars with APOGEE spectra in the DR14 dataset. This "APOGEE Net" has produced reliable predictions of log g for YSOs, with uncertainties of within 0.1 dex and a good agreement with the structure indicated by pre-main sequence evolutionary tracks, and correlate well with independently derived stellar radii. These values will be useful for studying pre-main sequence stellar populations to accurately diagnose membership and ages.

[13]  arXiv:2002.08399 [pdf, ps, other]

Title: The appearance of a compact jet in the soft-intermediate state of 4U 1543-47

Authors: D. M. Russell (NYU Abu Dhabi), P. Casella, E. Kalemci, A. Vahdat Motlagh, P. Saikia, S. F. Pirbhoy, D. Maitra

Comments: Accepted to MNRAS. 11 pages, 6 figures

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

Recent advancements in the understanding of jet-disc coupling in black hole candidate X-ray binaries (BHXBs) have provided close links between radio jet emission and X-ray spectral and variability behaviour. In 'soft' X-ray states the jets are suppressed, but the current picture lacks an understanding of the X-ray features associated with the quenching or recovering of these jets. Here we show that a brief, ~4 day infrared (IR) brightening during a predominantly soft X-ray state of the BHXB 4U 1543-47 is contemporaneous with a strong X-ray Type B quasi-periodic oscillation (QPO), a slight spectral hardening and an increase in the rms variability, indicating an excursion to the soft-intermediate state (SIMS). This IR 'flare' has a spectral index consistent with optically thin synchrotron emission and most likely originates from the steady, compact jet. This core jet emitting in the IR is usually only associated with the hard state, and its appearance during the SIMS places the 'jet line' between the SIMS and the soft state in the hardness-intensity diagram for this source. IR emission is produced in a small region of the jets close to where they are launched (~ 0.1 light-seconds), and the timescale of the IR flare in 4U 1543-47 is far too long to be caused by a single, discrete ejection. We also present a summary of the evolution of the jet and X-ray spectral/variability properties throughout the whole outburst, constraining the jet contribution to the X-ray flux during the decay.

[14]  arXiv:2002.08400 [pdf, other]

Title: Exploring galaxy colour in different environments of the cosmic web with SDSS

Authors: Biswajit Pandey, Suman Sarkar

Comments: 13 pages, 9 figures, 5 tables, Submitted to MNRAS

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

We analyze a set of volume limited samples from the SDSS to study the dependence of galaxy colour on different environments of the cosmic web. We measure the local dimension of the galaxies to determine their embedding environments and find that the filaments host a higher fraction of red galaxies than the sheets at each luminosity. At a fixed luminosity, the fraction of red galaxies in filaments and sheets increases with the size of these structures. This suggests that the bigger structures have a larger baryon reservoir favouring higher accretion rate and larger stellar mass. At a fixed length scale, the fraction of red galaxies monotonically increases in all the environments with increasing luminosity. We also find that the average colour of the red and blue populations are systematically higher in the environments with smaller local dimension and increases monotonically in all the environments with luminosity. We observe that the bimodal nature of the galaxy colour distribution persists in all environments and all luminosities suggesting that the transformation from blue to red galaxy can occur in all environments.

[15]  arXiv:2002.08401 [pdf, other]

Title: Determining the Neutrino Lifetime from Cosmology

Authors: Zackaria Chacko, Abhish Dev, Peizhi Du, Vivian Poulin, Yuhsin Tsai

Comments: 6 pages, 3 figures

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

We explore the cosmological signals of theories in which the neutrinos decay into invisible dark radiation after becoming non-relativistic. We show that in this scenario, near-future large scale structure measurements from the Euclid satellite, when combined with cosmic microwave background data from Planck, may allow an independent determination of both the lifetime of the neutrinos and the sum of their masses. These parameters can be independently determined because the Euclid data will cover a range of redshifts, allowing the growth of structure over time to be tracked. If neutrinos are stable on cosmological timescales, these observations can improve the lower limit on the neutrino lifetime by seven orders of magnitude, from $\mathcal{O}(10)$ years to $2\times 10^8$ years ($95\%$ C.L.), without significantly affecting the measurement of neutrino mass. On the other hand, if neutrinos decay after becoming non-relativistic but on timescales less than $\mathcal{O}(100)$ million years, these observations may allow, not just the first measurement of the sum of neutrino masses, but also the determination of the neutrino lifetime from cosmology.

[16]  arXiv:2002.08432 [pdf, other]

Title: Infrared Variability due to Magnetic Pressure Driven Jets, Dust Ejection and Quasi-Puffed-Up Inner Rims

Authors: Kurt Liffman, Geoffrey Bryan, Mark Hutchison, Sarah T. Maddison

Comments: 18 pages, 21 figures

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

The interaction between a YSO stellar magnetic field and its protostellar disc can result in stellar accretional flows and outflows from the inner disc rim. Gas flows with a velocity component perpendicular to disc midplane subject particles to centrifugal acceleration away from the protostar, resulting in particles being catapulted across the face of the disc. The ejected material can produce a "dust fan", which may be dense enough to mimic the appearance of a "puffed-up" inner disc rim. We derive analytic equations for the time dependent disc toroidal field, the disc magnetic twist, the size of the stable toroidal disc region, the jet speed and the disc region of maximal jet flow speed. We show how the observed infrared variability of the pre-transition disc system LRLL~31 can be modelled by a dust ejecta fan from the inner-most regions of the disc whose height is partially dependent on the jet flow speed. The greater the jet flow speed, the higher is the potential dust fan scale height. An increase in mass accretion onto the star tends to increase the height and optical depth of the dust ejection fan, increasing the amount of 1--8~$\mu$m radiation. The subsequent shadow reduces the amount of light falling on the outer disc and decreases the 8-- 40~$\mu$m radiation. A decrease in the accretion rate reverses this scenario, thereby producing the observed "see-saw" infrared variability.

[17]  arXiv:2002.08441 [pdf, ps, other]

Title: Diagnostics of plasma ionisation using torsional Alfén waves

Authors: Istvan Ballai

Comments: 4 pages

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

Using the recently observed torsional Alfv\'en waves in solar prominences, we determine the ionisation state of the plasma by taking into account that Alfv\'en waves propagate in a partially ionised prominence plasma. We derive the evolutionary equation of waves and compare the analytical solutions to observations to determine the number density of neutrals. Using a single fluid plasma approximation, where the wave damping is provided by the Cowling resistivity, we study the temporal evolution of waves. By comparing the solution of equations with observational data (period, amplitude, propagation speed), we determined the value of the Cowling resistivity that led us to draw a conclusion on the amount of neutrals in the partially ionised plasma, a quantity that cannot be measured directly or indirectly. Our results show that damped torsional Alfv\'en waves are an ideal diagnostic tool for the ionisation state of the plasma. Using a simple model, we find that at the observational temperature of torsional Alfv\'en waves, the number of neutrals is of the order of $5\times 10^{10}$ cm$^{-3}$.

[18]  arXiv:2002.08442 [pdf, other]

Title: Detection of the Red Supergiant Wind from the Progenitor of Cassiopeia A

Authors: Kathryn E. Weil, Robert A. Fesen, Daniel J. Patnaude, John C. Raymond, Roger A. Chevalier, Dan Milisavljevic, Christopher L. Gerardy

Comments: 19 pages, 9 figures, accepted to ApJ

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

Cassiopeia A (Cas A) is one of the best studied young Galactic supernova remnants. While providing a rare opportunity to study in detail the remnant of a Type IIb supernova, questions remain regarding the nature of its progenitor, its mass-loss history, and its pre-SN evolution. Here we present an optical investigation of the circumstellar environment around Cas A and find clumpy and filamentary Halpha emission nebulosities concentrated 10-15 pc (10-15 arcminutes) to the north and east. First reported by Minkowski as a faint H II region, these nebulosities exhibit distinct morphological and spectroscopic properties relative to the surrounding diffuse emissions. Compared to neighboring H II regions, these nebulae show stronger [N II] 6548, 6583 A and [S II] 6716, 6731 A emissions relative to Halpha. We show that Cas A's highest-velocity ejecta knots are interacting with some of the closest projected emission nebulae, thus providing strong evidence that these nebulae lie at the same distance as the remnant. We interpret these surrounding nebulosities to be the remains of the progenitor's red supergiant wind which accumulated against the southern edge of a large extended H II region located north of Cas A. Our findings are consistent with the view that Cas A's progenitor underwent considerable mass-loss, first from a fast main-sequence wind, then from a slower, clumpy red supergiant wind, and finally from a brief high-velocity wind, like that from a yellow supergiant.

[19]  arXiv:2002.08447 [pdf, ps, other]

Title: Cataclysmic Variables in the First Year of the Zwicky Transient Facility

Authors: Paula Szkody, Brooke Dicenzo, Anna Y. Q. Ho, Lynne A. Hillenbrand, Jan van Roestel, Margaret Ridder, Isabel DeJesus Lima, Melissa L. Graham, Eric C. Bellm, Kevin Burdge, Thomas Kupfer, Thomas A. Prince, Frank J. Masci, Przemyslaw J. Mroz, V. Zach Golkhou, Michael Coughlin, Virginia A. Cunningham, Richard Dekany, Matthew J. Graham, David Hale, David Kaplan, Mansi M. Kasliwal, Adam A. Miller, James D. Neill, Maria T. Patterson, Reed Riddle, Roger Smith, Maayanne T. Soumagnac

Comments: 27 pages, 9 figures, 3 tables

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

Using selection criteria based on amplitude, time and color, we have identified 329 objects as known or candidate cataclysmic variable (CVs) during the first year of testing and operation of the Zwicky Transient Facility (ZTF). Of these, 90 are previously confirmed CVs, 218 are strong candidates based on the shape and color of their light curves obtained during 3-562 days of observations, and the remaining 21 are possible CVs but with too few data points to be listed as good candidates. Almost half the strong candidates are within 10 deg of the galactic plane, in contrast to most other large surveys which have avoided crowded fields. The available Gaia parallaxes are consistent with sampling the low mass transfer CVs, as predicted by population models. Our followup spectra have confirmed Balmer/helium emission lines in 27 objects, with four showing high excitation HeII emission, including candidates for an AM CVn, a polar and an intermediate polar. Our results demonstrate that a complete survey of the galactic plane is needed to accomplish an accurate determination of the number of CVs existing in the Milky Way.

[20]  arXiv:2002.08472 [pdf, other]

Title: Prescriptions for Correcting Ultraviolet-Based Redshifts for Luminous Quasars at High Redshift

Authors: Cooper Dix (1), Ohad Shemmer (1), Michael S. Brotherton (2), Richard F. Green (3), Michelle Mason (2), Adam D. Myers (2) ((1) U. North Texas, (2) U. Wyoming, (3) U. Arizona)

Comments: 13 pages (emulateapj), 5 figures, Accepted for publication in ApJ

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

High-redshift quasars typically have their redshift determined from rest-frame ultraviolet (UV) emission lines. However, these lines, and more specifically the prominent C IV $\lambda 1549$ emission line, are typically blueshifted yielding highly uncertain redshift estimates compared to redshifts determined from rest-frame optical emission lines. We present near-infrared spectroscopy of 18 luminous quasars at $2.15 < z < 3.70$ that allows us to obtain reliable systemic redshifts for these sources. Together with near-infrared spectroscopy of an archival sample of 44 quasars with comparable luminosities and redshifts, we provide prescriptions for correcting UV-based redshifts. Our prescriptions reduce velocity offsets with respect to the systemic redshifts by $\sim140$ km s$^{-1}$ and reduce the uncertainty on the UV-based redshift by $\sim25\%$ with respect to the best method currently used for determining such values. We also find that the redshifts determined from the Sloan Digital Sky Survey Pipeline for our sources suffer from significant uncertainties, which cannot be easily mitigated. We discuss the potential of our prescriptions to improve UV-based redshift corrections given a much larger sample of high redshift quasars with near-infrared spectra.

[21]  arXiv:2002.08486 [pdf, other]

Title: The accuracy of post-processing nucleosynthesis

Authors: Eduardo Bravo

Comments: Submitted to MNRAS, 11 pages, 4 figures, 3 tables

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

The computational requirements posed by multi-dimensional simulations of type Ia supernovae make it difficult to incorporate complex nuclear networks to follow the release of nuclear energy along with the propagation of the flame. Instead, these codes usually model the flame and use simplified nuclear kinetics with the goal to determine a sufficiently accurate rate of nuclear energy generation and, afterwards, post-process the thermodynamic trajectories with a large nuclear network to obtain more reliable nuclear yields. In this work, I study the performance of simplified nuclear networks with respect to the reproduction of the correct nuclear yields. The first point I address is the definition of a strategy to follow the properties of matter in nuclear statistical equilibrium (NSE). I propose that the best approach is to use published tables of NSE properties together with a careful interpolation routine. Second, I test several simplified nuclear networks for the accuracy of the nucleosynthesis obtained through post-processing, compared with the nucleosynthesis resulting directly from a one-dimensional supernova code equipped with a large nuclear network. Short networks (iso7 and 13{\alpha}) are able to give an accurate yield of 56Ni, after post-processing, but can fail by order of magnitude predicting the ejected mass of even mildly abundant species (>0.001 solar masses). A network of 21 species reproduces the nucleosynthesis of Chandrasekhar and sub-Chandrasekhar explosions with average errors better than 20% for the whole set of stable elements and isotopes followed in the model.

[22]  arXiv:2002.08508 [pdf, other]

Title: How far actually is the Galactic Center IRS 13E3 from Sagittarius A$^{\ast}$?

Authors: Masato Tsuboi, Yoshimi Kitamura, Takahiro Tsutsumi, Ryosuke Miyawaki, Makoto Miyoshi, Atsushi Miyazaki

Comments: 9 pages, 2 figures, 1 table, Accepted for publication in PASJ

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

The Galactic Center IRS 13E cluster is a very intriguing IR object located at $\sim0.13$ pc from Sagittarius A$^\ast$ (Sgr A$^\ast$) in projection distance. There are both arguments for and against the hypothesis that a dark mass like an intermediate mass black hole (IMBH) exists in the cluster. Recently we have detected the rotating ionized gas ring around IRS 13E3, which belongs to the cluster, in the H30$\alpha$ recombination line using ALMA. The enclosed mass is derived to be $M_{\mathrm{encl.}}\simeq2\times10^4$ $M_\odot$, which agrees with an IMBH and is barely less than the astrometric upper limit mass of the IMBH around Sgr A$^\ast$. Because the limit mass depends on the true three-deminsional (3D) distance from Sgr A$^\ast$, it is very important to determine it observationally. However, the 3D distance is indefinite because it is hard to determine the line-of-sight (LOS) distance by usual methods. We would attempt to estimate the LOS distance by spectroscopic informations. The CH$_3$OH molecule is easily destroyed by cosmic ray around Sgr A$^{\ast}$. However, we detected a highly excited CH$_3$OH emission line in the ionized gas stream associated with IRS 13E3. This indicates that IRS 13E3 is located at $r\gtrsim 0.4$ pc from Sgr A$^{\ast}$.

[23]  arXiv:2002.08516 [pdf, other]

Title: The CGM at Cosmic Noon with KCWI: Outflows from a Star-forming Galaxy at $z=2.071$

Authors: Nikole M. Nielsen, Glenn G. Kacprzak, Stephanie K. Pointon, Michael T. Murphy, Christopher W. Churchill, Romeel Davé

Comments: 23 pages, 9 figures, 5 tables. Submitted to ApJ 5 Sep 2019, resubmitted to ApJ 19 Feb 2020

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

We present the first results from our CGM at Cosmic Noon with KCWI program to study gas flows in the circumgalactic medium (CGM) at $z=2-3$. Combining the power of a high-resolution VLT/UVES quasar spectrum, an HST/ACS image, and integral field spectroscopy with Keck/KCWI, we detected Lya emission from a $3.7L_{\ast}$ galaxy at $z_{\rm gal}=2.0711$ associated with a Lyman limit system with weak MgII ($W_r(2796)=0.24$ Ang) in quasar field J143040$+$014939. The galaxy is best modeled as a star-forming (SFR$_{\rm FUV}=37.8$ M$_{\odot}$ yr$^{-1}$) clumpy edge-on disk ($i=85^{\circ}$). The background quasar probes the galaxy at an impact parameter of $D=66$ kpc along the projected galaxy minor axis ($\Phi=89^{\circ}$). From photoionization modeling of the absorption system, which includes Lya, MgII, SiII, SiIII, SiIV, and CIV, we infer a total line-of-sight CGM metallicity of ${\rm [Si/H]}=-1.5^{+0.4}_{-0.3}$. The absorption system is roughly kinematically symmetric about the galaxy redshift, with a full MgII velocity spread of $\sim210$ km s$^{-1}$. Given the galaxy--quasar orientation, CGM metallicity, and gas kinematics, we interpret this gas as outflowing from the host galaxy. By modeling the absorption as a polar outflow cone, we find the gas is decelerating with radial velocity $V_{\rm out}=100-350$ km s$^{-1}$ for half opening angles of $\theta_0=20^{\circ}-80^{\circ}$. Assuming a constant $V_{\rm out}$, it would take $\sim190-650$ Myr for the gas to reach 66 kpc. The outflow is energetic, with a mass outflow rate of $\dot{M}_{\rm out}=45-51$ M$_{\odot}$ yr$^{-1}$ and mass loading factor of $\eta\sim1.3$. We aim to build a sample of $\sim50$ MgII absorber--galaxy pairs at this epoch to better understand gas flows when they are most actively building galaxies.

[24]  arXiv:2002.08519 [pdf, ps, other]

Title: Pulsars Detection by Machine Learning with Very Few Features

Authors: Haitao Lin, Xiangru Li, Ziying Luo

Comments: 13 pages, 7 figures

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Machine Learning (cs.LG)

It is an active topic to investigate the schemes based on machine learning (ML) methods for detecting pulsars as the data volume growing exponentially in modern surveys. To improve the detection performance, input features into an ML model should be investigated specifically. In the existing pulsar detection researches based on ML methods, there are mainly two kinds of feature designs: the empirical features and statistical features. Due to the combinational effects from multiple features, however, there exist some redundancies and even irrelevant components in the available features, which can reduce the accuracy of a pulsar detection model. Therefore, it is essential to select a subset of relevant features from a set of available candidate features and known as {\itshape feature selection.} In this work, two feature selection algorithms ----\textit{Grid Search} (GS) and \textit{Recursive Feature Elimination} (RFE)---- are proposed to improve the detection performance by removing the redundant and irrelevant features. The algorithms were evaluated on the Southern High Time Resolution University survey (HTRU-S) with five pulsar detection models. The experimental results verify the effectiveness and efficiency of our proposed feature selection algorithms. By the GS, a model with only two features reach a recall rate as high as 99\% and a false positive rate (FPR) as low as 0.65\%; By the RFE, another model with only three features achieves a recall rate 99\% and an FPR of 0.16\% in pulsar candidates classification. Furthermore, this work investigated the number of features required as well as the misclassified pulsars by our models.

[25]  arXiv:2002.08522 [pdf, other]

Title: Rapid Evolution of Volatile CO from the Protostellar Disk Stage to the Protoplanetary Disk Stage

Authors: Ke Zhang, Kamber R. Schwarz, Edwin A. Bergin

Comments: 10 pages, 3 figures, 2 tables. Accepted for publication in ApJL

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

Recent observations show that the CO gas abundance, relative to H$_2$, in many 1-10 Myr old protoplanetary disks may be heavily depleted, by a factor of 10-100 compared to the canonical interstellar medium value of 10$^{-4}$. When and how this depletion happens can significantly affect compositions of planetesimals and atmospheres of giant planets. It is therefore important to constrain if the depletion occurs already at the earliest protostellar disk stage. Here we present spatially resolved observations of C$^{18}$O, C$^{17}$O, and $^{13}$C$^{18}$O $J$=2-1 lines in three protostellar disks. We show that the C$^{18}$O line emits from both the disk and the inner envelope, while C$^{17}$O and $^{13}$C$^{18}$O lines are consistent with a disk origin. The line ratios indicate that both C$^{18}$O and C$^{17}$O lines are optically thick in the disk region, and only $^{13}$C$^{18}$O line is optically thin. The line profiles of the $^{13}$C$^{18}$O emissions are best reproduced by Keplerian gaseous disks at similar sizes as their mm-continuum emissions, suggesting small radial separations between the gas and mm-sized grains in these disks, in contrast to the large separation commonly seen in protoplanetary disks. Assuming a gas-to-dust ratio of 100, we find that the CO gas abundances in these protostellar disks are consistent with the ISM abundance within a factor of 2, nearly one order of magnitude higher than the average value of 1-10 Myr old disks. These results suggest that there is a fast, $\sim$1 Myr, evolution of the abundance of CO gas from the protostellar disk stage to the protoplanetary disk stage.

[26]  arXiv:2002.08529 [pdf, other]

Title: Excess C/H in Protoplanetary Disk Gas from Icy Pebble Drift across the CO Snowline

Authors: Ke Zhang, Arthur D. Bosman, Edwin A. Bergin

Comments: 9 pages, 4 figures, and 1 table. Accepted for publication in ApJL

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

The atmospheric composition of giant planets carries the information of their formation history. Superstellar C/H ratios are seen in atmospheres of Jupiter, Saturn, and various giant exoplanets. Also, giant exoplanets show a wide range of C/O ratio. To explain these ratios, one hypothesis is that protoplanets accrete carbon-enriched gas when a large number of icy pebbles drift across the CO snowline. Here we report the first direct evidence of an elevated C/H ratio in disk gas. We use two thermo-chemical codes to model the $^{13}$C$^{18}$O, C$^{17}$O, and C$^{18}$O (2-1) line spectra of the HD 163296 disk. We show that the gas inside the CO snowline ($\sim$70 au) has a C/H ratio of 1-2 times higher than the stellar value. This ratio exceeds the expected value substantially, as only 25-60% of the carbon should be in gas at these radii. Although we cannot rule out the case of a normal C/H ratio inside 70 au, the most probable solution is an elevated C/H ratio of 2-8 times higher than the expectation. Our model also shows that the gas outside 70 au has a C/H ratio of 0.1$\times$ the stellar value. This picture of enriched C/H gas at the inner region and depleted gas at the outer region is consistent with numerical simulations of icy pebble growth and drift in protoplanetary disks. Our results demonstrate that the large-scale drift of icy pebble can occur in disks and may significantly change the disk gas composition for planet formation.

[27]  arXiv:2002.08557 [pdf, other]

Title: Consequences of neutrino self interactions for weak decoupling and big bang nucleosynthesis

Authors: E. Grohs, George M. Fuller, Manibrata Sen

Comments: 24 pages, 5 figures

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

We calculate and discuss the implications of neutrino self-interactions for the physics of weak decoupling and big bang nucleosynthesis (BBN) in the early universe. In such neutrino-sector extensions of the standard model, neutrinos may not free-stream, yet can stay thermally coupled to one another. Nevertheless, the neutrinos exchange energy and entropy with the photon, electron-positron, and baryon component of the early universe only through the ordinary weak interaction. We examine the effects of neutrino self-interaction for the primordial helium and deuterium abundances and $N_{\rm eff}$, a measure of relativistic energy density at photon decoupling. These quantities are determined in, or may be influenced by, the physics in the weak decoupling epoch. Self interacting neutrinos have been invoked to address a number of anomalies, including as a possible means of ameliorating tension in the Hubble parameter. Our calculations show that surprisingly subtle changes in BBN accompany some of these neutrino self-interaction schemes. Such minute signals require high-precision measurements, making deuterium the best abundance for BBN constraints in the models explored here.

[28]  arXiv:2002.08564 [pdf, other]

Title: Corona-Heated Accretion-disk Reprocessing (CHAR): A Physical Model to Decipher the Melody of AGN UV/optical Twinkling

Authors: Mouyuan Sun (XMU), Yongquan Xue (USTC), W. N. Brandt (PSU), Wei-Min Gu (XMU), Jonathan R. Trump (UConn), Zhenyi Cai (USTC), Zhicheng He (USTC), Da-bin Lin (GXU), Tong Liu (XMU), Junxian Wang (USTC)

Comments: 25 pages, 25 figures. Accepted to ApJ. The two figsets can be downloaded from this https URL

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

Active galactic nuclei (AGNs) have long been observed to "twinkle" (i.e., their brightness varies with time) on timescales from days to years in the UV/optical bands. Such AGN UV/optical variability is essential for probing the physics of supermassive black holes (SMBHs), the accretion disk, and the broad-line region. Here we show that the temperature fluctuations of an AGN accretion disk, which is magnetically coupled with the corona, can account for observed high-quality AGN optical light curves. We calculate the temperature fluctuations by considering the gas physics of the accreted matter near the SMBH. We find that the resulting simulated AGN UV/optical light curves share the same statistical properties as the observed ones as long as the dimensionless viscosity parameter $\alpha$, which is widely believed to be controlled by magnetohydrodynamic (MHD) turbulence in the accretion disk, is about $0.01$---$0.2$. Moreover, our model can simultaneously explain the larger-than-expected accretion disk sizes and the dependence of UV/optical variability upon wavelength for NGC 5548. Our model also has the potential to explain some other observational facts of AGN UV/optical variability, including the timescale-dependent bluer-when-brighter color variability and the dependence of UV/optical variability on AGN luminosity and black hole mass. Our results also demonstrate a promising way to infer the black-hole mass, the accretion rate, and the radiative efficiency, thereby facilitating understanding of the gas physics and MHD turbulence near the SMBH and its cosmic mass growth history by fitting the AGN UV/optical light curves in the era of time-domain astronomy.

[29]  arXiv:2002.08566 [pdf, other]

Title: Atmospheric neutrinos in a next-generation xenon dark matter experiment

Authors: Jayden L. Newstead, Rafael F. Lang, Louis E. Strigari

Comments: 7 pages, 6 figures, code and results available at this https URL

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

We study the sensitivity of future xenon- and argon-based dark matter and neutrino detection experiments to low-energy atmospheric neutrinos. Not accounting for experimental backgrounds, the primary obstacle for identifying nuclear recoils induced by atmospheric neutrinos is the tail of the electron recoil distribution due to $pp$ solar neutrinos. We use the NEST code to model the solar and atmospheric neutrino signals in a xenon detector and find that an exposure of 700 tonne-years will produce a $5\sigma$ detection of atmospheric neutrinos. We explore the effect of different detector properties and find that a sufficiently long electron lifetime is essential to the success of such a measurement.

[30]  arXiv:2002.08588 [pdf, other]

Title: An AGB Star with a Thick Circumstellar Shell

Authors: Jeremy Mould, Mark Durré, Syed Uddin, Lifan Wang

Comments: 6 pages, 5 figures, accepted for publication in PASP

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

The Asymptotic Giant Branch (AGB) is the terminal phase of red giant evolution with timescales of millions of years and a total mass lost from the star that is a significant fraction of the initial mass. Investigation of one of these stars, WISEA J173046.10-344455.5, a kpc in the direction of the center of the Galaxy, reveals a cool oxygen rich star with a dust shell of black-body temperature 1305 K.

[31]  arXiv:2002.08593 [pdf, other]

Title: Heating of the Real Polar Cap of Radio Pulsars

Authors: Maciej Sznajder, Ulrich Geppert

Comments: Accepted for publication in MNRAS

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

The heating of the real polar cap surface of radio pulsars by the bombardment of ultra-relativistic charges is studied. The real polar cap is a significantly smaller area within or close by the conventional polar cap which is encircled by the last open field lines of the dipolar field $\vec{B}_d$. It is surrounded by those field lines of the small scale local surface field $\vec{B}_s$ that join the last open field lines of $\vec{B}_d$ in a height of $\sim 10^5$ cm above the cap. As the ratio of radii of the conventional and real polar cap $R_{dip}/R_{pc}\sim 10$, flux conservation requires $B_s/B_d\sim 100$. For rotational periods $P\sim 0.5$ s, $B_s\sim 10^{14}$ G creates a strong electric potential gap that forms the inner accelerating region (IAR) in which charges gain kinetic energies $\sim 3\times 10^{14}$ eV. This sets an upper limit for the energy that back flowing charges can release as heat in the surface layers of the real polar cap. Within the IAR, which is flown through with a dense stream of extremely energetic charges, no stable atmosphere of hydrogen can survive. Therefore, we consider the polar cap as a solidified "naked" surface consisting of fully ionized iron ions. We discuss the physical situation at the real polar cap, calculate its surface temperatures $T_s$ as functions of $B_s$ and $P$, and compare the results with X-ray observations of radio pulsars.

[32]  arXiv:2002.08600 [pdf, other]

Title: Stabilization of dayside surface liquid water via tropopause cold trapping on arid slowly rotating tidally locked planets

Authors: Feng Ding, Robin D. Wordsworth

Comments: accepted for publication in ApJL

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

Terrestrial-type exoplanets orbiting nearby red dwarf stars (M-dwarfs) are among the best targets for atmospheric characterization and biosignature searches in the near future. Recent evolutionary studies have suggested that terrestrial planets in the habitable zone of M-dwarfs are probably tidally locked and have limited surface water inventories as a result of their host stars' high early luminosities. Several previous climate simulations of such planets have indicated that their remaining water would be transported to the planet's permanent nightside and become trapped as surface ice, leaving the dayside devoid of water. Here we use a three-dimensional general circulation model with a water cycle and accurate radiative transfer scheme to investigate the surface water evolution on slowly rotating tidally locked terrestrial planets with limited surface water inventories. We show that there is a competition for water trapping between the nightside surface and the substellar tropopause in this type of climate system. Although under some conditions the surface water remains trapped on the nightside as an ice sheet, in other cases liquid water stabilizes in a circular area in the substellar region as a wetland. Planets with 1 bar N$_2$ and atmospheric CO$_2$ levels greater than 0.1 bar retain stable dayside liquid water, even with very small surface water inventories. Our results reveal the diversity of possible climate states on terrestrial-type exoplanets and highlight the importance of surface liquid water detection techniques for future characterization efforts.

[33]  arXiv:2002.08610 [pdf, other]

Title: Passive spirals and shock influenced star formation in the merging cluster A3376

Authors: Kshitija Kelkar, K. S. Dwarakanath, Bianca M. Poggianti, Alessia Moretti, Rogerio Monteiro-Oliveira, Rubens Machado, Gastao Lima-Neto, Jacopo Fritz, Benedetta Vulcani, Marco Gullieuszik, Daniela Bettoni

Comments: 15 pages, 12 figures, submitted to Monthly Notices of Royal Astronomy Society (MNRAS)

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

We present a detailed analysis of star formation properties of galaxies in a nearby ($z\sim0.046$) young ($\sim$0.6 Gyr) post-merger cluster system A3376, with a moderate shock front ( $v_{s}\sim$1630 km/s) observed as symmetric radio relics. Exploiting the spectroscopic data from the wide-field OmegaWINGS survey and the associated photometric information, our investigations reveal the plausible effects of the dynamic post-merger environment differing from the putative pre-merger cluster environment. The remnants of the pre-merger relaxed cluster environment are realised through the existence of passive spiral galaxies located in the central regions of the cluster between the two BCGs. We discover A3376 to contain a population of massive $(M_{*}/M_{\odot})>10$) blue regular star-forming spirals in regions of maximum merger shock influence but exhibiting star formation rates similar to those in relaxed clusters at similar epoch. We further discover low-mass (Log $(M_{*}/M_{\odot})\leq 10$) late-type blue PSBs which could either be formed as a result of rapid quenching of low-mass spirals following the shock-induced star formation or due to the intense surge in the ICM pressures at the beginning of the merger. With the possibility of the merger shock affecting high- and low-mass spirals differently, our results bridge the seemingly contradictory results observed in known merging cluster systems so far and establish that different environmental effects are at play right from pre- to post-merger stage.

[34]  arXiv:2002.08624 [pdf, other]

Title: Anticorrelated temperature-density profiles in the quiet solar corona and coronal mass ejections: Approach based on the spine-type Hamiltonians

Authors: Yu.V. Dumin

Comments: PDFLaTeX, aa documentclass, 4 pages, 5 PDF figures, submitted to Astronomy & Astrophysics

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

Context: The mechanism of the solar corona heating remains one of key problems in astrophysics for a few decades; but none of the proposed mechanisms can give a definitive answer to this question. As a result, the novel scenarios are still suggested. Aims: Here, we perform a critical consideration of the recently-proposed mechanism for the formation of the anticorrelated temperature and density profiles due to specific features of relaxation in the strongly non-equilibrium plasmas described by the so-called spin-type Hamiltonians [L. Casetti and S. Gupta, 2014, Eur. Phys. J. B 87, 91; T.N. Teles et al., 2015, Phys. Rev. E 92, 020101(R)]. Methods: We employ the universal property of the above-mentioned systems to produce the long-lived anticorrelated temperature-density distributions and analyse their most important qualitative features that should be expected in the context of the coronal plasmas. Results: As follows from our consideration, the anticorrelated profiles predicted by the spine-type Hamiltonians can be hardly relevant to explanation of the temperature distribution in the quiet solar corona. However, they might be interesting for the interpretation of the large-scale inhomogeneity of the powerful coronal mass ejections, possessing the filament-type structure.

[35]  arXiv:2002.08636 [pdf, other]

Title: Screening corrections to Electron Capture Rates and resulting constraints on Primordial Magnetic Fields

Authors: Yudong Luo, Michael A. Famiano, Toshitaka Kajino, Motohiko Kusakabe, A. Baha Balantekin

Comments: 18 pages, 7 figures, submitted to Phys. ReV. D

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

We explore screening effects arising from a relativistic magnetized plasma with applications to Big Bang nucleosynthesis (BBN). %Specifically, due to their small magnetic moments, energies of electrons and positrons can be easily quantized via Landau quantization. The screening potential which depends on the thermodynamics of charged particles in the plasma is altered by the magnetic field. We focus on the impact of screening on the electron capture interaction. Taking into account the correction in BBN arising from a homogeneous primordial magnetic field (PMF), we constrain the epoch at which the PMF was generated and its strength during BBN. Considering such screening corrections to the electron capture rates and using up-to-date observations of primordial elemental abundances, we also discuss the possibility of solving the problem of under-estimation of the deuterium abundance. We find for certain values of the PMF strength predicted D and $^4$He abundances are both consistent with the observational constraints.

[36]  arXiv:2002.08640 [pdf, ps, other]

Title: The ALMA Spectroscopic Survey in the HUDF: The Cosmic Dust and Gas Mass Densities in Galaxies up to $z\sim3$

Authors: Benjamin Magnelli, Leindert Boogaard, Roberto Decarli, Jorge Gónzalez-López, Mladen Novak, Gergö Popping, Ian Smail, Fabian Walter, Manuel Aravena, Roberto J. Assef, Franz Erik Bauer, Frank Bertoldi, Chris Carilli, Paulo C. Cortes, Elisabete da Cunha, Emanuele Daddi, Tanio Díaz-Santos, Hanae Inami, Robert J. Ivison, Olivier Le Fèvre, Pascal Oesch, Dominik Riechers, Hans-Walter Rix, Mark T. Sargent, Paul van der Werf, Jeff Wagg, Axel Weiss

Comments: 32 pages, 13 figures, Accepted for publication in ApJ

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

Using the deepest 1.2 mm continuum map to date in the Hubble Ultra Deep Field obtained as part of the ALMA Spectroscopic Survey (ASPECS) large program, we measure the cosmic density of dust and implied gas (H$_{2}+$H I) mass in galaxies as a function of look-back time. We do so by stacking the contribution from all $H$-band selected galaxies above a given stellar mass in distinct redshift bins, $\rho_{\rm dust}(M_\ast>M,z)$ and $\rho_{\rm gas}(M_\ast>M,z)$. At all redshifts, $\rho_{\rm dust}(M_\ast>M,z)$ and $\rho_{\rm gas}(M_\ast>M,z)$ grow rapidly as $M$ decreases down to $10^{10}\,M_\odot$, but this growth slows down towards lower stellar masses. This flattening implies that at our stellar mass-completeness limits ($10^8\,M_\odot$ and $10^{8.9}\,M_\odot$ at $z\sim0.4$ and $z\sim3$), both quantities converge towards the total cosmic dust and gas mass densities in galaxies. The cosmic dust and gas mass densities increase at early cosmic time, peak around $z\sim2$, and decrease by a factor $\sim4$ and 7, compared to the density of dust and molecular gas in the local universe, respectively. The contribution of quiescent galaxies -- i.e., with little on-going star-formation -- to the cosmic dust and gas mass densities is minor ($\lesssim10\%$). The redshift evolution of the cosmic gas mass density resembles that of the star-formation rate density, as previously found by CO-based measurements. This confirms that galaxies have relatively constant star-formation efficiencies (within a factor $\sim2$) across cosmic time. Our results also imply that by $z\sim0$, a large fraction ($\sim90\%$) of dust formed in galaxies across cosmic time has been destroyed or ejected to the intergalactic medium.

[37]  arXiv:2002.08690 [pdf, other]

Title: High-resolution spectroscopy and spectropolarimetry of the total lunar eclipse January 2019

Authors: K. G. Strassmeier, I. Ilyin, E. Keles, M. Mallonn, A. Järvinen, M. Weber, F. Mackebrandt, J. M. Hill

Comments: Accepted for publication in Astronomy & Astrophysics

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

Observations of the Earthshine off the Moon allow for the unique opportunity to measure the large-scale Earth atmosphere. Another opportunity is realized during a total lunar eclipse which, if seen from the Moon, is like a transit of the Earth in front of the Sun. We thus aim at transmission spectroscopy of an Earth transit by tracing the solar spectrum during the total lunar eclipse of January 21, 2019. Time series spectra of the Tycho crater were taken with the Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in its polarimetric mode in Stokes IQUV at a spectral resolution of 130000 (0.06 \AA). In particular, the spectra cover the red parts of the optical spectrum between 7419-9067 \AA . The spectrograph's exposure meter was used to obtain a light curve of the lunar eclipse. The brightness of the Moon dimmed by 10.75 mag during umbral eclipse. We found both branches of the O$_2$ A-band almost completely saturated as well as a strong increase of H$_2$O absorption during totality. The deep penumbral spectra show significant excess absorption from the NaI 5890 \AA doublet, the CaII infrared triplet around 8600 \AA, and the KI line at 7699 \AA in addition to several hyper-fine-structure lines of MnI and even from BaII. The detections of the latter two elements are likely due to an untypical solar center-to-limb effect rather than Earth's atmosphere. The absorption in CaII and KI remained visible throughout umbral eclipse. A small continuum polarization of the O$_2$ A-band of 0.12\% during umbral eclipse was detected at 6.3$\sigma$. No line polarization of the O$_2$ A-band, or any other spectral-line feature, is detected outside nor inside eclipse. It places an upper limit of $\approx$0.2\% on the degree of line polarization during transmission through Earth's atmosphere and magnetosphere.

[38]  arXiv:2002.08705 [pdf, other]

Title: Multicolor Optical Monitoring of the Blazar S5 0716+714 from 2017 to 2019

Authors: Dingrong Xiong, Jinming Bai, Junhui Fan, Dahai Yan, Minfeng Gu, Xuliang Fan, Jirong Mao, Nan Ding, Rui Xue, Weimin Yi

Comments: 27 pages, 9 figures, 4 tables, accepted for publication in ApJS

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

We continuously monitored the blazar S5 0716+714 in the optical $g$, $r$ and $i$ bands from Nov. 10, 2017 to Jun. 06, 2019. The total number of observations is 201 nights including 26973 data points. This is a very large quasi-simultaneous multicolor sample for the blazar. The average time spans and time resolutions are 3.4 hours and 2.9 minutes per night, respectively. During the period of observations, the target source in the $r$ band brightens from $14^{\rm m}.16$ to $12^{\rm m}.29$ together with five prominent sub-flares, and then first becomes fainter to $14^{\rm m}.76$ and again brightens to $12^{\rm m}.94$ with seven prominent sub-flares. For the long-term variations, we find a strong flatter when brighter (FWB) trend at a low flux state and then a weak FWB trend at a higher flux state. A weak FWB trend at a low flux state and then a strong FWB trend at a higher flux state are also reported. Most of sub-flares show the strong FWB trends, except for two flares with a weak FWB trend. The particle acceleration and cooling mechanisms together with the superposition of different FWB-slopes from sub-flares are likely to explain the optical color behaviours. A scenario of bent jet is discussed.

[39]  arXiv:2002.08707 [pdf, ps, other]

Title: On the turbulence driving mode of expanding HII regions

Authors: Shyam H. Menon, Christoph Federrath, Rolf Kuiper

Comments: 10 pages, 6 figures. Accepted for publication in MNRAS

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

We investigate the turbulence driving mode of ionizing radiation from massive stars on the surrounding interstellar medium (ISM). We run hydrodynamical simulations of a turbulent cloud impinged by a plane-parallel ionization front. We find that the ionizing radiation forms pillars of neutral gas reminiscent of those seen in observations. We quantify the driving mode of the turbulence in the neutral gas by calculating the driving parameter $b$, which is characterised by the relation $\sigma_s^2 = \ln({1+b^2\mathcal{M}^2})$ between the variance of the logarithmic density contrast $\sigma_s^2$ (where $s = \ln({\rho/\rho_0})$ with the gas density $\rho$ and its average $\rho_0$), and the turbulent Mach number $\mathcal{M}$. Previous works have shown that $b\sim1/3$ indicates solenoidal (divergence-free) driving and $b\sim1$ indicates compressive (curl-free) driving, with $b\sim1$ producing up to ten times higher star formation rates than $b\sim1/3$. The time variation of $b$ in our study allows us to infer that ionizing radiation is inherently a compressive turbulence driving source, with a time-averaged $b\sim 0.76 \pm 0.08$. We also investigate the value of $b$ of the pillars, where star formation is expected to occur, and find that the pillars are characterised by a natural mixture of both solenoidal and compressive turbulent modes ($b\sim0.4$) when they form, and later evolve into a more compressive turbulent state with $b\sim0.5$--$0.6$. A virial parameter analysis of the pillar regions supports this conclusion. This indicates that ionizing radiation from massive stars may be able to trigger star formation by producing predominately compressive turbulent gas in the pillars.

[40]  arXiv:2002.08727 [pdf, other]

Title: Coherent radio emission from a quiescent red dwarf indicative of star-planet interaction

Authors: H. K. Vedantham, J. R. Callingham, T. W. Shimwell, C. Tasse, B. J. S. Pope, M. Bedell, I. Snellen, P. Best, M. J. Hardcastle, M. Haverkorn, A. Mechev, S. P. O'Sullivan, H. J. A. Röttgering, G. J. White

Comments: Accepted version

Journal-ref: Vedantham, H.K., Callingham, J.R., Shimwell, T.W. et al. Coherent radio emission from a quiescent red dwarf indicative of star-planet interaction. Nat Astron (2020)

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

Low frequency ($\nu\lesssim 150\,$MHz) stellar radio emission is expected to originate in the outer corona at heights comparable to and larger than the stellar radius. Such emission from the Sun has been used to study coronal structure, mass ejections, space-weather conditions around the planets (Schwenn 2006). Searches for low-frequency emission from other stars have only detected a single active flare-star (Lynch et al. 2017) that is not representative of the wider stellar population. Here we report the detection of low-frequency radio emission from a quiescent star, GJ 1151--- a member of the most common stellar type (red dwarf or spectral class M) in the Galaxy. The characteristics of the emission are similar to those of planetary auroral emissions (Zarka 1998) (e.g. Jupiter's decametric emission), suggesting a coronal structure dominated by a global magnetosphere with low plasma density. Our results show that large-scale currents that power radio aurorae operate over a vast range of mass and atmospheric composition, ranging from terrestrial planets to main-sequence stars. The Poynting flux required to produce the observed radio emission cannot be generated by GJ 1151's slow rotation, but can originate in a sub-Alfv\'{e}nic interaction of its magnetospheric plasma with a short-period exoplanet. The emission properties are consistent with theoretical expectations (Zarka 2007; Lanza 2009; Saur et al. 2013; Turnpenney et al. 2018) for interaction with an Earth-size planet in a $\sim 1-5$ day-long orbit.

[41]  arXiv:2002.08728 [pdf, ps, other]

Title: Comparative Spectral Analysis of the Superluminous Supernova 2019neq

Authors: R. Konyves-Toth, B. P. Thomas, J. Vinko, J. C. Wheeler

Comments: 14 pages, submitted to ApJ

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

We present a detailed spectroscopic analysis of the recently discovered fast evolving Type I superluminous supernova (SLSN-I), SN 2019neq (at redshift z = 0.1059) comparing it to the well-studied slow evolving SLSN-I, SN 2010kd (z = 0.101). Our investigation concentrates on optical spectra taken during the photospheric phase. The observations of SN 2019neq were carried out with the 10m Hobby-Eberly Telescope (HET) Low Resolution Spectrograph-2 (LRS2) at McDonald Observatory. We apply the SYN++ code to model the spectra taken at -4 days, +5 days and +29 days from maximum light. We examine the chemical evolution and ejecta composition of the SLSN by identifying the elements and ionization states in its spectra. Our analysis confirms that SN 2019neq is a fast evolving SLSN-I. We derive the number density of each ionization state at the epoch of the three observations. Finally, we give constraints on the lower limit of the ejecta mass and find a hint for a possible relation between the evolution timescale and the ejected mass of SLSNe-I.

[42]  arXiv:2002.08734 [pdf, other]

Title: Is an upturn commonly seen in Fermi-LAT GRB afterglow spectra?

Authors: Xin-Bo He, Pak-Hin Thomas Tam, Guang-Bo Long, Yong Zhang (Sun Yat-sen Univ)

Comments: 14 pages, 5 figures, 1 table, submitted

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

We analyzed 199 GRBs detected by Fermi-LAT during the years 2008-2019. We found 67 photons at energies >=10 GeV, which come from 34 GRBs. Out of these 34 GRBs, Fermi-LAT detects significant (TS>=4) afterglow 0.1-200 GeV photons from 25 GRBs. We present time-integrated 0.1-200 GeV spectra of these 25 GRBs. The spectra of a significant fraction (9/25) of these GRBs revealed a harder component above an energy break of 0.3-2 GeV. While shock synchrotron may account for the photons at the lower energy end, high energy photons above the break is naturally explained by synchrotron self-Compton (SSC) emission. We perform broadband model fit to the X-ray-LAT emission of GRB 131231A. Comparing the afterglow spectra of these 25 GRBs with other Fermi-LAT detected GRBs, we found that the power-law index distribution is similar for the two populations. This may indicate that the additional high-energy component may also exist in Fermi-LAT GRBs in general.

[43]  arXiv:2002.08745 [pdf, other]

Title: Variability and transient search in the SUDARE-VOICE field: a new method to extract the light curves

Authors: Dezi Liu, Wenqiang Deng, Zuhui Fan, Liping Fu, Giovanni Covone, Mattia Vaccari, Mario Radovich, Massimo Capaccioli, Demetra De Cicco, Aniello Grado, Lucia Marchetti, Nicola Napolitano, Maurizio Paolillo, Giuliano Pignata, Fabio Ragosta

Comments: 13 pages, 12 figures. MNRAS accepted

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

The VST Optical Imaging of the CDFS and ES1 Fields (VOICE) Survey, in synergy with the SUDARE survey, is a deep optical $ugri$ imaging of the CDFS and ES1 fields using the VLT Survey Telescope (VST). The observations for the CDFS field comprise about 4.38 deg$^2$ down to $r\sim26$ mag. The total on-sky time spans over four years in this field, distributed over four adjacent sub-fields. In this paper, we use the multi-epoch $r$-band imaging data to measure the variability of the detected objects and search for transients. We perform careful astrometric and photometric calibrations and point spread function (PSF) modeling. A new method, referring to as differential running-average photometry, is proposed to measure the light curves of the detected objects. With the method, the difference of PSFs between different epochs can be reduced, and the background fluctuations are also suppressed. Detailed uncertainty analysis and detrending corrections on the light curves are performed. We visually inspect the light curves to select variable objects, and present some objects with interesting light curves. Further investigation of these objects in combination with multi-band data will be presented in our forthcoming paper.

[44]  arXiv:2002.08746 [pdf, other]

Title: A census of main-sequence interactions in the Multiple Star Catalog

Authors: Adrian S. Hamers

Comments: Submitted to MNRAS. 15 pages, 11 figures

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

Statistics of hierarchical systems containing three or more stars are continuously improving. The Multiple Star Catalog (MSC) is currently the most comprehensive catalogue of multiple-star systems and contains component masses, orbital periods, and additional information. The systems in the MSC are interesting for several reasons, including the long-term dynamical evolution of few-body systems. Although the secular evolution of triples and quadruples has been explored before, a systematic study of the systems in the MSC including also quintuples and sextuples has not been carried out. Here, we explore the main-sequence (MS) evolution of stars from the MSC based on approximately 2x10^5 secular dynamical integrations. We estimate statistical probabilities for strong interactions during the MS such as tidal evolution and mass transfer, and the onset of dynamical instability. Depending on the assumed model for the unknown orbital elements, we find that the fraction of noninteracting systems is largest for triples (~0.9), and decreases to ~0.6-0.8 for sextuples. The fraction of strong interactions increases from ~0.1 to ~0.2 from triples to sextuples, and the fraction of dynamically unstable systems increases from ~0.001 to ~0.1-0.2. The larger fractions of strong interactions and dynamical instability in systems with increasing multiplicity can be attributed to increasingly complex secular evolution in these systems. Our results indicate that a significant fraction of high-multiplicity systems interact or become dynamically unstable already during the MS, with an increasing importance as the number of stars increases.

[45]  arXiv:2002.08756 [pdf, other]

Title: Modeling the Early Evolution of a Slow Coronal Mass Ejection Imaged by the Parker Solar Probe

Authors: Alexis P. Rouillard, Nicolas Poirier, Michael Lavarra, Antony Bourdelle, Kévin Dalmasse, Athanasios Kouloumvakos, Angelos Vourlidas, Valbona Kunkel, Phillip Hess, Russ A. Howard, Guillermo Stenborg, Nour E. Raouafi

Comments: 19 pages, 10 figures, to appear in ApJS, 2 animations of Figure 2 available at this https URL and this https URL

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

During its first solar encounter, the Parker Solar Probe (PSP) acquired unprecedented up-close imaging of a small Coronal Mass Ejection (CME) propagating in the forming slow solar wind. The CME originated as a cavity imaged in extreme ultraviolet that moved very slowly ($<50$ km/s) to the 3-5 solar radii (R$_\odot$) where it then accelerated to supersonic speeds. We present a new model of an erupting Flux Rope (FR) that computes the forces acting on its expansion with a computation of its internal magnetic field in three dimensions. The latter is accomplished by solving the Grad-Shafranov equation inside two-dimensional cross sections of the FR. We use this model to interpret the kinematic evolution and morphology of the CME imaged by PSP. We investigate the relative role of toroidal forces, momentum coupling, and buoyancy for different assumptions on the initial properties of the CME. The best agreement between the dynamic evolution of the observed and simulated FR is obtained by modeling the two-phase eruption process as the result of two episodes of poloidal flux injection. Each episode, possibly induced by magnetic reconnection, boosted the toroidal forces accelerating the FR out of the corona. We also find that the drag induced by the accelerating solar wind could account for about half of the acceleration experienced by the FR. We use the model to interpret the presence of a small dark cavity, clearly imaged by PSP deep inside the CME, as a low-density region dominated by its strong axial magnetic fields.

[46]  arXiv:2002.08759 [pdf, other]

Title: The BepiColombo SERENA/ELENA Instrument On-Ground Testing with the ELENA Special Check Out Equipment (SCOE)

Authors: Francesco Lazzarotto (1), Nello Vertolli (1), Dario Maschietti (3), Andrea Maria Di Lellis (3), Jouni Ryno (5), Fabio Camozzi (6), Stefano Orsini (1), Anna Milillo (1), Alessandro Mura (1), Elisabetta De Angelis (1), Rosanna Rispoli (1), Luca Colasanti (1), Stefano Selci (2), Marco D'Alessandro (2), Roberto Leoni (4), Francesco Mattioli (4) ((1) INAF-IAPS Rome Italy,(2) ISM-CNR Rome Italy,(3) AMDL srl Rome Italy,(4) IFN-CNR Rome Italy,(5) FMI Helsinki Finland,(6) OHB-Italia Milan Italy)

Comments: Proceedings of the European Ground System Architecture Workshop (ESAW) 18-19 June 2013 ESA/ESOC, Darmstadt, Germany

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

The neutral particles sensor ELENA (Emitted Low Energy Neutral Atoms) for the ESA/JAXA BepiColombo mission to Mercury (in the SERENA instrument suite) is devoted to measure low energetic neutral atoms. The main goal of the experiment is measuring the sputtering emission from planetary surfaces, from E=20eV up to E=5keV, within 1D (2 deg. x 76 deg. ). ELENA original project had also a particle discrimination system based on Time-of-Flight (TOF) of particles through the shutter on the Micro Channel Plates detector (MCP), it has been withdrawn from the flight model due to design and development problems. The ELENA SCOE is the configuration/testing system of ELENA, it allows to command operations and to set up configuration parameters on the instrument and to monitor the incoming data. The TC/TM simulation/encoding/decoding software is developed respecting the CCSDS/ECSS standards implemented by ESA, and it's SCOS2000 compatible. TC generation, HK data monitoring and basic science data analysis are operated by the SERENA EGSE, developed by the Finnish Meteorological Institute (FMI), Helsinki, Finland. The data stream outcoming from the EGSE is then preprocessed from TM to user readable formats: FITS and then ASCII csv tables with metadata collected in a detached XML file, called label. This task is performed using the PacketLib, ProcessorLib, and DISCoS (PPD) framework and is going to be used as the first level prototype of the BepiColombo Science Ground Segment processing pipeline, based in ESAC, Madrid, Spain and implemented using the PDS4 data format.

[47]  arXiv:2002.08776 [pdf]

Title: Observational Constraints on the Great Filter

Authors: Jacob Haqq-Misra, Ravi Kumar Kopparapu, Edward Schwieterman

Comments: Accepted for publication in Astrobiology

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

The search for spectroscopic biosignatures with the next-generation of space telescopes could provide observational constraints on the abundance of exoplanets with signs of life. An extension of this spectroscopic characterization of exoplanets is the search for observational evidence of technology, known as technosignatures. Current mission concepts that would observe biosignatures from ultraviolet to near-infrared wavelengths could place upper limits on the fraction of planets in the galaxy that host life, although such missions tend to have relatively limited capabilities of constraining the prevalence of technosignatures at mid-infrared wavelengths. Yet search-ing for technosignatures alongside biosignatures would provide important knowledge about the future of our civilization. If planets with technosignatures are abundant, then we can increase our confidence that the hardest step in planetary evolution--the Great Filter--is probably in our past. But if we find that life is commonplace while technosignatures are absent, then this would in-crease the likelihood that the Great Filter awaits to challenge us in the future.

[48]  arXiv:2002.08794 [pdf, ps, other]

Title: Transit of asteroids across the 7/3 Kirkwood gap under the Yarkovsky effect

Authors: Yang-Bo Xu (1), Li-Yong Zhou (1), Wing-Huen Ip (2) ((1) Nanjing University, (2) Nantional Central University)

Comments: 10 pages, 10 figures. Accepted by A&A

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

Many asteroids in the main belt are continuously pushed by Yarkovsky effect into regions of different mean motion resonances (MMRs) and then ejected out. They are considered as the principal source of near-Earth objects. We investigate in this paper the effects of the 7/3 MMR with Jupiter (J7/3 MMR) on the transportation of asteroids from Koronis and Eos families that reside respectively on the inner and outer side of the resonance. The fraction of asteroids that make successful crossing through the resonance and the escaping rate from the resonance are found to depend on the Yarkovsky drifting rate, the initial inclination and the migrating direction. The excitation of eccentricity and inclination due to the combined influence from both the resonance and Yarkovsky effect is discussed. Only the eccentricity can be pumped up considerably, and it is attributed mainly to the resonance. In the observational data, family members are also found in the resonance and on the opposite side of the resonance with respect to the corresponding family centre. The existence of these family members is explained using our results of numerical simulations. Finally, the replenishment of asteroids in the J7/3 MMR and the transportation of asteroids by it are discussed.

[49]  arXiv:2002.08806 [pdf, ps, other]

Title: Solar-cycle irradiance variations over the last four billion years

Authors: Anna V. Shapiro, Alexander I. Shapiro, Laurent Gizon, Natalie A. Krivova, Sami K. Solanki

Comments: 8 pages, 6 figures, accepted publication for Astronomy&Astrophysics

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

The variability of the spectral solar irradiance (SSI) over the course of the 11-year solar cycle is one of the manifestations of solar magnetic activity. There is a strong evidence that the SSI variability has an effect on the Earth's atmosphere. The faster rotation of the Sun in the past lead to a more vigorous action of solar dynamo and thus potentially to larger amplitude of the SSI variability on the timescale of the solar activity cycle. This could led to a stronger response of the Earth's atmosphere as well as other solar system planets' atmospheres to the solar activity cycle. We calculate the amplitude of the SSI and TSI variability over the course of the solar activity cycle as a function of solar age. We employ the relationship between the stellar magnetic activity and the age based on observations of solar twins. Using this relation we reconstruct solar magnetic activity and the corresponding solar disk area coverages by magnetic features (i.e. spots and faculae) over the last four billion years. These disk coverages are then used to calculate the amplitude of the solar-cycle SSI variability as a function of wavelength and solar age. Our calculations show that the young Sun was significantly more variable than the present Sun. The amplitude of the solar-cycle Total Solar Irradiance (TSI) variability of the 600 Myr old Sun was about 10 times larger than that of the present Sun. Furthermore, the variability of the young Sun was spot-dominated (the Sun being brighter at the activity minimum than in the maximum), i.e. the Sun was overall brighter at activity minima than at maxima. The amplitude of the TSI variability decreased with solar age until it reached a minimum value at 2.8 Gyr. After this point, the TSI variability is faculae-dominated (the Sun is brighter at the activity maximum) and its amplitude increases with age.

[50]  arXiv:2002.08812 [pdf, other]

Title: Lifting the dust veil from the Globular Cluster Palomar2

Authors: Charles Bonatto, Ana Chies-Santos

Comments: Accepted for publication by MNRAS

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

This work employs high-quality {\em Hubble Space Telescope} ({\em HST}) Advanced Camera for Surveys (ACS) F606W and F814W photometry to correct for the differential reddening affecting the colour-magnitude diagram (CMD) of the poorly-studied globular cluster (GC) Palomar\,2. Differential reddening is taken into account by assuming that morphological differences among CMDs extracted across the field of view of Palomar\,2 correspond essentially to shifts (quantified in terms of $\delta E(B-V)$) along the reddening vector due to a non-uniform dust distribution. The average reddening difference over all partial CMDs is $\overline{\delta E(B-V)}=0.24\pm0.08$, with the highest reaching $\delta E(B-V) =0.52$. The corrected CMD displays well-defined and relatively narrow evolutionary sequences, especially for the evolved stars, i.e. the red-giant, horizontal and asymptotic giant branches (RGB, HB and AGB, respectively). The average width of the upper main sequence and RGB profiles of the corrected CMD corresponds to 56\% of the original one. Parameters measured on this CMD show that Palomar\,2 is $\approx13.25$\,Gyr old, has the mass $M\sim1.4\times10^5\,m_\odot$ stored in stars, is affected by the foreground $E(B-V)\approx0.93$, is located at $d_\odot\approx26$\,Kpc from the Sun, and is characterized by the global metallicity $Z/Zo\approx0.03$, which corresponds to the range $-1.9\leq [Fe/H] \leq-1.6$ (for $0.0\leq[\alpha/Fe]\leq+0.4$), quite consistent with other outer halo GCs. Additional parameters are the absolute magnitude $M_V\approx-7.8$, and the core and half-light radii $r_C\approx2.6$\,pc and $R_{HL}\approx4.7$\,pc, respectively.

[51]  arXiv:2002.08846 [pdf, other]

Title: Neutrino effects on the morphology of cosmic large-scale structure

Authors: Yu Liu, Yu Yu, Hao-Ran Yu, Pengjie Zhang

Comments: 8 pages, 2 figures, Accepted for publication in PRD

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

In this work, we propose a powerful probe of neutrino effects on the large-scale structure (LSS) of the Universe, i.e., Minkowski functionals (MFs). The morphology of LSS can be fully described by four MFs. This tool, with strong statistical power, is robust to various systematics and can comprehensively probe all orders of N-point statistics. By using a pair of high-resolution N-body simulations, for the first time, we comprehensively studied the subtle neutrino effects on the morphology of LSS. For an ideal LSS survey of volume $\sim1.73$ Gpc$^3$/$h^3$, neutrino signals are mainly detected from void regions with a significant level up to $\thicksim 10\sigma$ and $\thicksim 300\sigma$ for CDM and total matter density fields, respectively. This demonstrates its enormous potential for much improving the neutrino mass constraint in the data analysis of up-coming ambitious LSS surveys.

[52]  arXiv:2002.08847 [pdf]

Title: Potassium Isotopic Compositions of Enstatite Meteorites

Authors: Chen Zhao, Katharina Lodders, Hannah Bloom, Heng Chen, Zhen Tian, Piers Koefoed, Maria K. Peto, Kun Wang

Comments: 46 pages, 7 figures, 2 tables, published in Meteoritics & Planetary Science

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

Enstatite chondrites and aubrites are meteorites that show the closest similarities to the Earth in many isotope systems that undergo mass-independent and mass-dependent isotope fractionations. Due to the analytical challenges to obtain high-precision K isotopic compositions in the past, potential differences in K isotopic compositions between enstatite meteorites and the Earth remained uncertain. We report the first high-precision K isotopic compositions of eight enstatite chondrites and four aubrites and find that there is a significant variation of K isotopic compositions among enstatite meteorites (from -2.34 permil to -0.18 permil). However, K isotopic compositions of nearly all enstatite meteorites scatter around the Bulk Silicate Earth (BSE) value. The average K isotopic composition of the eight enstatite chondrites (-0.47 +/- 0.57 permil) is indistinguishable from the BSE value (-0.48 +/- 0.03 permil), thus further corroborating the isotopic similarity between Earth' building blocks and enstatite meteorite precursors. We found no correlation of K isotopic compositions with the chemical groups, petrological types, shock degrees, and terrestrial weathering conditions; however, the variation of K isotopes among enstatite meteorite can be attributed to the parent body processing. Our sample of the main group aubrite MIL 13004 is exceptional and has an extremely light K isotopic composition (delta 41K= -2.34 +/- 0.12 permil). We attribute this unique K isotopic feature to the presence of abundant djerfisherite inclusions in our sample because this K-bearing sulfide mineral is predicted to be enriched in 39K during equilibrium exchange with silicates.

[53]  arXiv:2002.08850 [pdf, other]

Title: The SUPERWIDE Catalog: A Catalog of 99,203 Wide Binaries Found in Gaia and Supplemented by the SUPERBLINK High Proper Motion Catalog

Authors: Zachary Hartman, Sébastien Lépine

Comments: 38 Pages, 34 Figures, Accepted to ApJS, Comments are welcome

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

We present a catalog of 99,203 wide binary systems, initially identified as common proper motion (CPM) pairs from a subset of ~5.2 million stars with proper motions $\mu > 40$ mas/year, selected from Gaia data release 2 (DR2) and the SUPERBLINK high proper motion catalog. CPM pairs are found by searching for pairs of stars with angular separations $< 1$ degree and proper motion differences $\Delta\mu < 40$ mas/year. A Bayesian analysis is then applied in two steps. In a first pass, we use proper motion differences and angular separations to distinguish between binaries and chance alignments. In a second pass, we use parallax data from Gaia DR2 to refine our Bayesian probability estimates. We present a table of 119,390 pairs which went through the full analysis, 99,203 of which have probabilities $>95\%$ of being real binaries. Of those 99,203 high probability pairs, we estimate that only about 364 pairs are most likely to be false positives. In addition, we identify 57,506 pairs which have probabilities $>10\%$ from the first pass but have high parallax errors and therefore were not vetted in the second pass. We examine the projected physical separation distribution of our highest probability pairs and note that the distribution is a simple exponential tail and shows no evidence of being bi-modal. Among pairs with lower probability, wide binaries are detected at larger separations ($>10^{4-5}$ AU) consistent with the very wide population suggested in previous studies, however our analysis suggests that these do not represent a distinct population. We examine the HR diagram of this set of high probability wide binaries and find evidence for 980 over-luminous components among 2,227 K+K wide binaries; assuming these represent unresolved sub-systems, we determine that the higher order multiplicity fraction for K+K wide systems is at least 39.6\%.

[54]  arXiv:2002.08868 [pdf]

Title: A crucial test for astronomical spectrograph calibration with frequency combs

Authors: Rafael A. Probst, Dinko Milaković, Borja Toledo-Padrón, Gaspare Lo Curto, Gerardo Avila, Anna Brucalassi, Bruno L. Canto Martins, Izan de Castro Leão, Massimiliano Esposito, Jonay I. González Hernández, Frank Grupp, Theodor W. Hänsch, Hanna Kellermann, Florian Kerber, Olaf Mandel, Antonio Manescau, Eszter Pozna, Rafael Rebolo, José Renan de Medeiros, Tilo Steinmetz, Alejandro Suárez Mascareño, Thomas Udem, Josefina Urrutia, Yuanjie Wu, Luca Pasquini, Ronald Holzwarth

Comments: 22 pages, 14 figures. View the Nature Astronomy publication under this https URL . Nature Astronomy article available under this https URL

Journal-ref: Nature Astronomy (2020)

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

Laser frequency combs (LFCs) are well on their way to becoming the next-generation calibration sources for precision astronomical spectroscopy. This development is considered key in the hunt for low-mass rocky exoplanets around solar-type stars whose discovery with the radial-velocity method requires cm/s Doppler precision. In order to prove such precise calibration with an LFC, it must be compared to another calibrator of at least the same precision. Being the best available spectrograph calibrator, this means comparing it to a second - fully independent - LFC. This test had long been pending, but our installation of two LFCs at the ultra-stable spectrograph HARPS presented the so far unique opportunity for simultaneous calibrations with two separate LFCs. Although limited in time, the test results confirm the 1 cm/s stability that has long been anticipated by the astronomical community.

[55]  arXiv:2002.08919 [pdf, ps, other]

Title: Switches between accretion structures during flares in 4U 1901+03

Authors: L. Ji, L. Ducci, A. Santangelo, S. Zhang, V. Suleimanov, S. Tsygankov, V. Doroshenko, A. Nabizadeh, S. N. Zhang, M. Y. Ge, L. Tao, Q. C. Bu, J. L. Qu, F. J. Lu, L. Chen, L. M. Song, T. P. Li, Y. P. Xu, X. L. Cao, Y. Chen, C. Z. Liu, C. Cai, Z. Chang, G. Chen, T. X. Chen, Y. B. Chen, Y. P. Chen, W. Cui, W. W. Cui, J. K. Deng, Y. W. Dong, Y. Y. Du, M. X. Fu, G. H. Gao, H. Gao, M. Gao, Y. D. Gu, J. Guan, C. C. Guo, D. W. Han, Y. Huang, J. Huo, S. M. Jia, L. H. Jiang, W. C. Jiang, J. Jin, L. D. Kong, B. Li, C. K. Li, G. Li, M. S. Li, W. Li, X. Li, X. B. Li, X. F. Li, Y. G. Li, Z. W. Li, X. H. Liang, J. Y. Liao, G. Q. Liu, H. X. Liu, H. W. Liu, X. J. Liu, Y. N. Liu, B. Lu, X. F. Lu, Q. Luo, T. Luo, X. Ma, B. Meng, Y. Nang, J. Y. Nie, G. Ou, X. Q. Ren, N. Sai, X. Y. Song, L. Sun, Y. Tan, Y. L. Tuo, et al. (44 additional authors not shown)

Comments: 11 pages, 8 figures, accepted for publication in MNRAS

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

We report on our analysis of the 2019 outburst of the X-ray accreting pulsar 4U 1901+03 observed with Insight-HXMT and NICER. Both spectra and pulse profiles evolve significantly in the decaying phase of the outburst. Dozens of flares are observed throughout the outburst. They are more frequent and brighter at the outburst peak. We find that the flares, which have a duration from tens to hundreds of seconds, are generally brighter than the persistent emission by a factor of $\sim$ 1.5. The pulse profile shape during the flares can be significantly different than that of the persistent emission. In particular, a phase shift is clearly observed in many cases. We interpret these findings as direct evidence of changes of the pulsed beam pattern, due to transitions between the sub- and super-critical accretion regimes on a short time scale. We also observe that at comparable luminosities the flares' pulse profiles are rather similar to those of the persistent emission. This indicates that the accretion on the polar cap of the neutron star is mainly determined by the luminosity, i.e., the mass accretion rate.

[56]  arXiv:2002.08921 [pdf, ps, other]

Title: Molecular environments of the supernova remnant G359.1-0.5

Authors: L. K. Eppens (1 and 2), E. M. Reynoso (1), J. Lazendic-Galloway (3), J. A. Combi (2 and 4), J. F. Albacete Colombo (5)- ((1) IAFE, Argentina, (2) FCAGLP, Argentina, (3) School of Physics and Astronomy, Monash University, Australia, (4) IAR, Argentina and (5) UNRN, Sede Atlantica, Argentina)

Comments: Accepted for publication in Monthly Notices of the Royal Astronomical Society

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

We report new CO observations and a detailed molecular-line study of the mixed morphology (MM) supernova remnant (SNR) G359.1-0.5, which contains six OH (1720 MHz) masers along the radio shell, indicative of shock-cloud interaction. Observations of 12CO and 13CO J:1-0 lines were performed in a 38x38 arcmin area with the on-the-fly technique using the Kit Peak 12 Meter telescope. The molecular study has revealed the existence of a few clumps with densities around 1,000 cm$^{-3}$ compatible in velocity and position with the OH (1720 MHz) masers. These clumps, in turn, appear to be part of a larger, elongated molecular structure ~34 arcmin long extending between -12.48 and +1.83 km/s, adjacent to the western edge of the radio shell. According to the densities and relative position with respect to the masers, we conclude that the CO clouds depict unshocked gas, as observed in other remnants with OH (1720 MHz) masers. In addition, we investigated the distribution of the molecular gas towards the adjacent gamma-ray source HESS J1745-303 but could not find any morphological correlation between the gamma-rays and the CO emission at any velocity in this region.

[57]  arXiv:2002.08942 [pdf, other]

Title: Constraining dark photons and their connection to 21 cm cosmology with CMB data

Authors: Kyrylo Bondarenko, Josef Pradler, Anastasia Sokolenko

Comments: 9 pages, 7 figures

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

In the inhomogeneous Universe, the cosmological conversion of dark photons into ordinary photons (and vice versa) may happen at a great number of resonance redshifts. This alters the CMB observed energy spectrum and degree of small-scale anisotropies. We utilize results from the EAGLE simulation to obtain the conversion probability along random line-of-sights to quantify these effects. We then apply our results to the case where dark photons are sourced by dark matter decay and their high-redshift conversion into ordinary photons modify the global 21 cm signal expected from the cosmic dawn era. Concretely, we show that a significant portion of the parameter space for which a converted population of photons in the Rayleigh-Jeans tail of the CMB explains the absorption strength observed by EDGES, is ruled out from the brightness temperature measurements of COBE/FIRAS and the CMB anisotropy measurements of Planck and SPT.

[58]  arXiv:2002.08951 [pdf, other]

Title: Bayesian Inference of Dense Matter Equation of State within Relativistic Mean Field Models using Astrophysical Measurements

Authors: Silvia Traversi, Prasanta Char, Giuseppe Pagliara

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)

We present a Bayesian analysis to constrain the equation of state of dense nucleonic matter by exploiting the available data from symmetric nuclear matter at saturation and from observations of compact X-ray sources and from the gravitational wave event GW170817. For the first time, such analysis is performed by using a class of models, the relativistic mean field models, which allow to consistently construct an equation of state in a wide range of densities, isospin asymmetries and temperatures. The selected class of models contains five nuclear physics empirical parameters at saturation for which we construct the joint posterior distributions. By exploring different types of priors, we find that the equations of state with the largest evidence are the ones featuring a strong reduction of the effective mass of the nucleons in dense matter which can be interpreted as an indication of a phase transition to a chiral symmetry restored phase. Those equations of state in turn predict $R_{1.4} \sim 12$ km. Finally, we present a preliminary investigation on the effect of including $\Lambda$ hyperons showing that they appear in stars more massive than about $1.6 M_{\odot}$ and lead to radii larger than about $R_{1.4} \sim 14$ km. Within the model here explored, the formation of such particles provide a poor agreement with the constraints from GW170817.

[59]  arXiv:2002.08952 [pdf, other]

Title: Spectroscopically Confirmed Lyman-Alpha Emitters from Redshift 5 to 7 Behind Ten Galaxy Cluster Lenses

Authors: Spencer Fuller, Brian Lemaux, Maruša Bradač, Austin Hoag, Kasper Schmidt, Kuang Huang, Victoria Strait, Charlotte Mason, Tommaso Treu, Laura Pentericci, Michele Trenti, Alaina Henry, Matt Malkan

Comments: 21 pages, 10 figures, submitted to ApJ

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

We present 36 spectroscopically confirmed intrinsically UV-faint Ly$\alpha$ emitting galaxies from follow-up observations with Keck/DEIMOS of gravitationally lensed high-redshift candidates. Candidates were selected to be between $5\lesssim z \lesssim 7$ from photometric data using \textit{HST} and \textit{Spitzer} imaging surveys. We used photometric redshift information to perform an integrated photometric redshift probability cut $>1\%$ between $5<z<7$ to construct a sample of 198 high-redshift objects. Our high-redshift sample spans intrinsic UV luminosities from a few $L^*$ down to $0.001L^*$. We identified 19 high-confidence detections of Ly$\alpha$ and an additional 17 likely detections. We divided our sample into lower-redshift ($z\sim5.5$) and higher-redshift ($z\sim6.5$) bins and ran Monte Carlo trials, incorporating the strength of the Ly$\alpha$ emission and the photometric redshift of the non-detections. Considering only objects where Ly$\alpha$ could be detected at EW(Ly$\alpha$)$>$25{\AA} at $3\sigma$ at the fiducial depth of our survey, and only those galaxies with EW(Ly$\alpha$)$>$25{\AA} as true LAEs, and finally, only objects with $m_{AB}<26.8$, we found the LAE fraction to be flat, or modestly increase from 0.26$\pm0.04$ to 0.30$\pm0.04$. These values relative to those for lower-redshift samples are consistent with a rising LAE fraction with redshift out to $z\sim6$, but at $z\sim6.5$ there is some tension between our results and results from surveys at intrinsically brighter luminosities. We conclude intrinsically fainter galaxies have Ly$\alpha$ emission, and there is a steep drop in the LAE fraction from our high-redshift sample at $z\sim6.5$ and from similar galaxies at $z\sim7.5$. This likely indicates we are witnessing the tail end of the epoch of reionization, as such a drop is not expected due to changes of intrinsic galaxy properties between these redshifts.

Cross-lists for Fri, 21 Feb 20

[60]  arXiv:2002.07586 (cross-list from gr-qc) [pdf, ps, other]

Title: Geodesics of the hyperbolically symmetric black hole

Authors: L. Herrera, A. Di Prisco, J. Ospino, L. Witten

Comments: 8 pages Revtex. 4 figures

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

We carry out a systematic study on the motion of test particles in the region inner to the horizon of a hyperbolically symmetric black hole. The geodesic equations are written and analyzed in detail. The obtained results are contrasted with the corresponding results obtained for the spherically symmetric case. It is found that test particles experience a repulsive force within the horizon, which prevents them to reach the center. These results are obtained for radially moving particles as well as for particles moving in the $\theta-R$ subspace. To complement our study we calculate the precession of a gyroscope moving along a circular path (non--geodesic) within the horizon. We obtain that the precession of the gyroscope is retrograde in the rotating frame, unlike the precession close to the horizon ($R=2m+\epsilon$) in the Schwarzschild spacetime, which is forward.

[61]  arXiv:2002.08370 (cross-list from hep-ph) [pdf, other]

Title: Robust cosmological constraints on axion-like particles

Authors: Paul Frederik Depta, Marco Hufnagel, Kai Schmidt-Hoberg

Comments: 21 pages, 6 figures

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

Axion-like particles with masses in the keV-GeV range have a profound impact on the cosmological evolution of our Universe, in particular on the abundance of light elements produced during Big Bang Nucleosynthesis. The resulting limits are complementary to searches in the laboratory and provide valuable additional information regarding the validity of a given point in parameter space. A potential drawback is that altering the cosmological history may potentially weaken or even fully invalidate these bounds. The main objective of this article is therefore to evaluate the robustness of cosmological constraints on axion-like particles in the keV-GeV region, allowing for various additional effects which may weaken the bounds of the standard scenario. Employing the latest determinations of the primordial abundances as well as information from the cosmic microwave background we find that while bounds can indeed be weakened, very relevant robust constraints remain.

[62]  arXiv:2002.08383 (cross-list from gr-qc) [pdf, other]

Title: Modeling the gravitational wave signature of neutron star black hole coalescences: PhenomNSBH

Authors: Jonathan E. Thompson, Edward Fauchon-Jones, Sebastian Khan, Elisa Nitoglia, Francesco Pannarale, Tim Dietrich, Mark Hannam

Comments: 11 pages, 5 figures

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

Accurate gravitational-wave (GW) signal models exist for black-hole binary (BBH) and neutron-star binary (BNS) systems, which are consistent with all of the published GW observations to date. Detections of a third class of compact-binary systems, neutron-star-black-hole (NSBH) binaries, have not yet been confirmed, but are eagerly awaited in the near future. For NSBH systems, GW models do not exist across the viable parameter space of signals. In this work we present the frequency-domain phenomenological model, PhenomNSBH, for GWs produced by NSBH systems with mass ratios from equal-mass up to 15, spin on the black hole up to a dimensionless spin of $|\chi|=0.5$, and tidal deformabilities ranging from 0 (the BBH limit) to 5000. We extend previous work on a phenomenological amplitude model for NSBH systems to produce an amplitude model that is parameterized by a single tidal deformability parameter. This amplitude model is combined with an analytic phase model describing tidal corrections. The resulting approximant is accurate enough to be used to measure the properties of NSBH systems for signal-to-noise ratios (SNRs) up to 50, and is compared to publicly-available NSBH numerical-relativity simulations and hybrid waveforms constructed from numerical-relativity simulations and tidal inspiral approximants. For most signals observed by second-generation ground-based detectors within this SNR limit, it will be difficult to use the GW signal alone to distinguish single NSBH systems from either BNSs or BBHs, and therefore to unambiguously identify an NSBH system.

[63]  arXiv:2002.08559 (cross-list from gr-qc) [pdf, other]

Title: Probing string-inspired gravity with the inspiral-merger-ringdown consistency tests of gravitational waves

Authors: Zack Carson, Kent Yagi

Comments: 13 pages, 3 figures

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

The extreme-gravity collisions between black holes allow us to probe the underlying theory of gravity. We apply the theory-agnostic inspiral-merger-ringdown consistency test to an example theory beyond general relativity for the first time. Here we focus on the string-inspired Einstein-dilaton Gauss-Bonnet gravity and modify the inspiral, ringdown, and remnant black hole properties of the gravitational waveform. We found that future multiband observations allow us to constrain the theory stronger than current observations by an order of magnitude. The formalism developed here can easily be applied to other theories.

[64]  arXiv:2002.08821 (cross-list from gr-qc) [pdf, other]

Title: A Distant Origin For Magnified LIGO/Virgo Black Holes Implied By Binary Component Masses

Authors: T. Broadhurst, J.M. Diego, G.F. Smoot

Comments: 2 figures

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

The primary and secondary masses of the binary black holes (BBH) reported by LIGO/Virgo are correlated with a narrow dispersion that appears to increase in proportion to mass. The mean binary mass ratio $1.45\pm0.07$ we show is consistent with pairs drawn randomly from the mass distribution of black holes in our Galaxy. However, BBH masses are concentrated around $\simeq 30M_\odot$, whereas black holes in our Galaxy peak at $\simeq 10M_\odot$. This mass difference can be reconciled by gravitational lensing magnification which allows distant events to be detected with typically $z\simeq 2$, so the waveform is reduced in frequency by $1+z$, and hence the measured chirp masses appear 3 times larger than their intrinsic values. This redshift enhancement also accounts for the dispersion of primary and secondary masses, both of which should increase as $1+z$, thereby appearing to scale with mass, in agreement with the data. Thus the BBH component masses provide independent support for lensing, implying most high chirp mass events have intrinsic masses like the stellar mass black holes in our Galaxy, coalescing at $z>1$, with only two low mass BBH detections, of $\simeq 10M_\odot$ as expected for unlensed events in the local Universe, $z\simeq 0.1$. This lensing solution requires a rapidly declining BBH event rate below $z<1$, which together with the observed absence of BBH spin suggests most events originate within young globular clusters at $z>1$, via efficient binary capture of stellar mass black holes with randomly oriented spins.

[65]  arXiv:2002.08879 (cross-list from gr-qc) [pdf, other]

Title: Neutron and quark stars: constraining the parameters for simple EoS using the GW170817

Authors: Griselda Arroyo-Chávez, Alejandro Cruz-Osorio, F. D. Lora-Clavijo, Cuauhtemoc Campuzano Vargas, Luis Alejandro García Mora

Comments: 7 pages, 4 figures and 1 table

Journal-ref: Astrophysics and Space Science (2020)

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

It is well known that the equation of state (EoS) of compact objects like neutron and quark stars is not determined despite there are several sophisticated models to describe it. From the electromagnetic observations, summarized in \cite{Lattimer01}, and the recent observation of gravitational waves from binary neutron star inspiral GW170817 \cite{Abbott2017_etal} and GW190425 \cite{Abbott2019}, it is possible to make an estimation of the range of masses and so constraint the mass of the neutron and quark stars, determining not only the best approximation for the EoS, but which kind of stars we would be observing. In this paper we explore several configurations of neutron stars assuming a simple polytropic equation of state, using a single layer model without crust. In particular, when the EoS depends on the mass rest density, $p=K \rho_{0}^{\Gamma}$, and when it depends on the energy density $p=K \rho^{\Gamma}$, considerable differences in the mass-radius relationships are found. On the other hand, we also explore quark stars models using the MIT bag EoS for different values of the vacuum energy density $B$.

[66]  arXiv:2002.08883 (cross-list from eess.SP) [pdf]

Title: Datasets of ionospheric parameters provided by SCINDA GNSS receiver from Lisbon airport area

Authors: Tatiana Barlyaeva, Teresa Barata, Anna Morozova

Comments: arXiv admin note: text overlap with arXiv:1910.04044

Subjects: Signal Processing (eess.SP); Instrumentation and Methods for Astrophysics (astro-ph.IM); Atmospheric and Oceanic Physics (physics.ao-ph)

Here we present datasets provided by a SCINDA GNSS receiver installed in Lisbon airport area from November of 2014 to July of 2019. The installed equipment is a NovAtel EURO4 with a JAVAD Choke-Ring antenna. The data are in the archived format and include the general messages on quality of records (*.msg), random number generator files (*.rng), raw observables as the signal-to-noise (S/N) ratios, pseudoranges and phases (*.obs), receiver position information (*.psn), ionosphere scintillations monitor (*.ism) and ionospheric parameters: total electron content, TEC, rate of change of TEC, ROTI, and the scintillation index S4 (*.scn). The presented data cover the full 2015 year. The raw data are of 1-minute resolution and available for each of receiver-satellite pairs. The processing and the analysis of the ionosphere scintillation datasets can be done using a dedicated "SCINDA-Iono" toolbox for MATLAB developed by T. Barlyaeva (2019) and available online via MathWorks File Exchange system. The toolbox allows to calculate 1-hour means for ionospheric parameters both for each of available receiver-satellite pairs and averaged over all available satellites during the analyzed hour. Here we present also the processed data for the following months in 2015: March, June, October, and December. The months were selected as containing most significant geomagnetic events of 2015. The 1-hour means for other months can be obtained from the raw data using, e.g. the aforementioned toolbox. The provided datasets can be of interest for the GNSS and ionosphere scientific communities.

[67]  arXiv:2002.08893 (cross-list from hep-ph) [pdf, ps, other]

Title: Comment on A dark matter interpretation of excesses in multiple direct detection experiments [arXiv:2002.06937]

Authors: Alan E. Robinson, Émile Michaud

Comments: 2 pages

Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Materials Science (cond-mat.mtrl-sci); High Energy Physics - Experiment (hep-ex); Instrumentation and Detectors (physics.ins-det)

In their recent preprint [arXiv:2002.06937], Kurinsky, Baxter, Kahn, and Krnjaic assume an unphysical ionization yield for plasmon excitations in order to claim a possible dark matter signal. Their proposed signal is not possible based on known physics, but their proposed detection method warrants further investigation.

Replacements for Fri, 21 Feb 20

[68]  arXiv:1804.10890 (replaced) [pdf, ps, other]

Title: Neutrino signal from proto-neutron star evolution: Effects of opacities from charged-current-neutrino interactions and inverse neutron decay

Authors: Tobias Fischer, Gang Guo, Alan A. Dzhioev, Gabriel Martínez-Pinedo, Meng-Ru Wu, Andreas Lohs, Yong-Zhong Qian

Comments: 16 pages, 7 figures

Journal-ref: Phys. Rev. C 101, 025804 (2020)

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)

[69]  arXiv:1903.08585 (replaced) [pdf, ps, other]

Title: Numerical Simulations of Gravitational Waves from Early-Universe Turbulence

Authors: Alberto Roper Pol, Sayan Mandal, Axel Brandenburg, Tina Kahniashvili, Arthur Kosowsky

Comments: 10 pages, 8 figures, 2 tables, submitted to PRD

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

[70]  arXiv:1904.11896 (replaced) [pdf, other]

Title: Loose Ends for the Exomoon Candidate Host Kepler-1625b

Authors: Alex Teachey, David Kipping, Christopher J. Burke, Ruth Angus, Andrew W. Howard

Comments: 21 pages, 4 tables, 11 figures. Accepted for publication in The Astronomical Journal, January 2020

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

[71]  arXiv:1905.09283 (replaced) [pdf, other]

Title: Pre-Supernova Neutrinos in Large Dark Matter Direct Detection Experiments

Authors: Nirmal Raj, Volodymyr Takhistov, Samuel J. Witte

Comments: 11 pages, 6 figures, 3 tables; v3: extended discussion on backgrounds, minor improvements, matches published version

Journal-ref: Phys. Rev. D 101, 043008 (2020)

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

[72]  arXiv:1908.00889 (replaced) [pdf, other]

Title: On standardizing kilonovae and their use as standard candles to measure the Hubble constant

Authors: Michael W. Coughlin, Tim Dietrich, Jack Heinzel, Nandita Khetan, Sarah Antier, Mattia Bulla, Nelson Christensen, David A. Coulter, Ryan J. Foley

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

[73]  arXiv:1908.03610 (replaced) [pdf, other]

Title: Optimising Automatic Morphological Classification of Galaxies with Machine Learning and Deep Learning using Dark Energy Survey Imaging

Authors: Ting-Yun Cheng, Christopher J. Conselice, Alfonso Aragón-Salamanca, Nan Li, Asa F. L. Bluck, Will G. Hartley, James Annis, David Brooks, Peter Doel, Juan García-Bellido, David J. James, Kyler Kuehn, Nikolay Kuropatkin, Mathew Smith, Flavia Sobreira, Gregory Tarle

Comments: 20 pages, 19 figures. Accepted to MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM)

[74]  arXiv:1908.10866 (replaced) [pdf, other]

Title: Faint rapid red transients from Neutron star -- CO white-dwarf mergers

Authors: Yossef Zenati, Alexey Bobrick, Hagai B. Perets

Comments: Accepted for publication by MNRAS

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

[75]  arXiv:1909.10946 (replaced) [pdf, other]

Title: Forecast for FAST: from Galaxies Survey to Intensity Mapping

Authors: Wenkai Hu, Xin Wang, Fengquan Wu, Yougang Wang, Pengjie Zhang, Xuelei Chen

Comments: replaced with revised version, 17 pages, 18 figures

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

[76]  arXiv:1911.05793 (replaced) [pdf, other]

Title: Extended FLRW Models: dynamical cancellation of cosmological anisotropies

Authors: Mikjel Thorsrud, Ben D. Normann, Thiago S. Pereira

Comments: 31 pages, 2 figures; v2: minor amendments to match the version published in CQG

Journal-ref: Class. Quantum Grav. 37 (2020) 065015

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

[77]  arXiv:1911.07530 (replaced) [pdf, other]

Title: The Sun at TeV energies: gammas, neutrons, neutrinos and a cosmic ray shadow

Authors: Miguel Gutiérrez, Manuel Masip

Comments: 9 pages, version to appear in Astroparticle Physics

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

[78]  arXiv:1912.07499 (replaced) [pdf, ps, other]

Title: The turbulent stress spectrum in the inertial and subinertial ranges

Authors: Axel Brandenburg, Stanislav Boldyrev

Comments: 7 pages, 9 figures, ApJ, in press

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA); Fluid Dynamics (physics.flu-dyn)

[79]  arXiv:1912.10498 (replaced) [pdf, other]

Title: The Statistics of Extended Debris Disks Measured with Gaia and Planck

Authors: Jacob Nibauer, Eric Baxter, Bhuvnesh Jain

Comments: 21 pages, 15 figures

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)

[80]  arXiv:1912.10841 (replaced) [pdf, other]

Title: Wideband 67-116 GHz receiver development for ALMA Band 2

Authors: P. Yagoubov, T. Mroczkowski, V. Belitsky, D. Cuadrado-Calle, F. Cuttaia, G. A. Fuller, J.-D. Gallego, A. Gonzalez, K. Kaneko, P. Mena, R. Molina, R. Nesti, V. Tapia, F. Villa, M. Beltran, F. Cavaliere, J. Ceru, G. E. Chesmore, K. Coughlin, C. De Breuck, M. Fredrixon, D. George, H. Gibson, J. Golec, A. Josaitis, F. Kemper, M. Kotiranta, I. Lapkin, I. Lopez-Fernandez, G. Marconi, S. Mariotti, W. McGenn, J. McMahon, A. Murk, F. Pezzotta, N. Phillips, N. Reyes, S. Ricciardi, M. Sandri, M. Strandberg, L. Terenzi, L. Testi, B. Thomas, Y. Uzawa, D. Vigano, N. Wadefalk

Comments: 23 pages, accepted for publication in A&A on 20 Dec 2019. This version corrects the affiliations of 2 co-authors

Journal-ref: A&A 634, A46 (2020)

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Instrumentation and Detectors (physics.ins-det)

[81]  arXiv:2001.00642 (replaced) [pdf, other]

Title: The (re)appearance of NGC 925 ULX-3, a new transient ULX

Authors: Hannah P. Earnshaw, Marianne Heida, Murray Brightman, Felix Fürst, Fiona A. Harrison, Amruta Jaodand, Matthew J. Middleton, Timothy P. Roberts, Rajath Sathyaprakash, Daniel Stern, Dominic J. Walton

Comments: 9 pages, 3 figures, 1 table. Accepted for publication in ApJ; updated to accepted version with minor revisions

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

[82]  arXiv:2001.07536 (replaced) [pdf, other]

Title: Resolving the $H_0$ tension with diffusion

Authors: Alejandro Perez, Daniel Sudarsky, Edward Wilson-Ewing

Comments: 12 pages. v2: Minor changes

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

[83]  arXiv:2001.08297 (replaced) [pdf, other]

Title: The establishment of the Standard Cosmological Model through observations

Authors: Ricardo T. Génova-Santos (IAC)

Comments: Accepted for publication in the book "Reviews in Frontiers of Modern Astrophysics: From Space Debris to Cosmology" (eds Kabath, Jones and Skarka; publisher Springer Nature) funded by the European Union Erasmus+ Strategic Partnership grant "Per Aspera Ad Astra Simul" 2017-1-CZ01-KA203-035562

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

[84]  arXiv:2002.00106 (replaced) [pdf, ps, other]

Title: Orbital dynamics of highly probable but rare Orionid outbursts possibly observed by the ancient Maya

Authors: J. H. Kinsman, D. J. Asher

Comments: Accepted 2020 January 17. Received 2020 January 3; in original form 2019 May 30. 9 pages, 4 figures

Journal-ref: Monthly Notices of the Royal Astronomical Society, 493 (2020) 551-558

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); History and Philosophy of Physics (physics.hist-ph)

[85]  arXiv:2002.00957 (replaced) [pdf, ps, other]

Title: The WISSH quasars project VIII. The impact of extreme radiative field in the accretion disk and X-ray corona interplay

Authors: L. Zappacosta, E. Piconcelli, M. Giustini, G. Vietri, F. Duras, G. Miniutti, M. Bischetti, A. Bongiorno, M. Brusa, M. Chiaberge, A. Comastri, C. Feruglio, A. Luminari, A. Marconi, C. Ricci, C. Vignali, F. Fiore

Comments: 10 pages (including Appendix), 4 figures. Astronomy & Astrophysics Letters in press. New version to match the journal version

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

[86]  arXiv:2002.06158 (replaced) [pdf, other]

Title: Characterizing low contrast Galactic open clusters with GAIA DR2

Authors: M. S. Angelo, J. F. C. Santos Jr, W. J. B. Corradi

Comments: 19 pages, 5 figures. Accept for publication in MNRAS

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

[87]  arXiv:2002.07625 (replaced) [pdf, other]

Title: Scalar-tensor extension of Natural Inflation

Authors: Guillem Simeon

Comments: 4 pages, 1 figure, clarifications added

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

[88]  arXiv:2002.07644 (replaced) [pdf, other]

Title: A systematic approach to realising quantum filters for high-precision measurements using network synthesis theory

Authors: Joe Bentley, Hendra Nurdin, Yanbei Chen, Haixing Miao

Subjects: Quantum Physics (quant-ph); Instrumentation and Methods for Astrophysics (astro-ph.IM)

[89]  arXiv:2002.07847 (replaced) [pdf, other]

Title: The Solar wind prevents re-accretion of debris after Mercury's giant impact

Authors: Christopher Spalding, Fred C. Adams

Comments: 14 pages, 6 Figures, Accepted for publication in The Planetary Science Journal (AAS journals)

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

• New submissions
• Cross-lists
• Replacements