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New submissions for Fri, 3 Apr 20

[1]  arXiv:2004.00625 [pdf, other]

Title: Experimental constraints on the ordinary chondrite shock darkening caused by asteroid collisions

Authors: T. Kohout, E. V. Petrova, G. A. Yakovlev, V. I. Grokhovsky, A. Penttilä, A. Maturilli, J.-G. Moreau, S. V. Berzin, J. Wasiljeff, I. A. Danilenko, D. A. Zamyatin, R. F. Muftakhetdinova, M. Heikkilä

Journal-ref: Astronomy & Astrophysics, manuscript no. 37593, 2020

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

Shock-induced changes in ordinary chondrite meteorites related to impacts or planetary collisions are known to be capable of altering their optical properties. Thus, one can hypothesize that a significant portion of the ordinary chondrite material may be hidden within the observed dark C/X asteroid population. The exact pressure-temperature conditions of the shock-induced darkening are not well constrained. Thus, we experimentally investigate the gradual changes in the chondrite material optical properties as a function of the shock pressure. A spherical shock experiment with Chelyabinsk LL5 was performed in order to study the changes in its optical properties. The spherical shock experiment geometry allows for a gradual increase of shock pressure from $\sim$15 GPa at a rim toward hundreds of gigapascals in the center. Four distinct zones were observed with an increasing shock load. The optical changes are minimal up to $\sim$50 GPa. In the region of $\sim$50--60 GPa, shock darkening occurs due to the troilite melt infusion into silicates. This process abruptly ceases at pressures of $\sim$60 GPa due to an onset of silicate melting. At pressures higher than $\sim$150 GPa, recrystallization occurs and is associated with a second-stage shock darkening due to fine troilite-metal eutectic grains. The shock darkening affects the ultraviolet, visible, and near-infrared (UV, VIS, and NIR) region while changes to the MIR spectrum are minimal. Shock darkening is caused by two distinct mechanisms with characteristic pressure regions, which are separated by an interval where the darkening ceases. This implies a reduced amount of shock-darkened material produced during the asteroid collisions.

[2]  arXiv:2004.00627 [pdf, other]

Title: INTEGRAL constraints on primordial black holes and particle dark matter

Authors: Ranjan Laha, Julian B. Muñoz, Tracy R. Slatyer

Comments: 9 pages, 5 figures

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

The International Gamma-Ray Astrophysics Laboratory (INTEGRAL) satellite has yielded unprecedented measurements of the soft gamma-ray spectrum of our Galaxy. Here we use those measurements to set constraints on dark matter (DM) that decays or annihilates into photons with energies $E\approx 0.02-2$ MeV. First, we revisit the constraints on decaying and annihilating particle DM. For DM decaying to two photons, we find that previous limits were overstated by roughly an order of magnitude. Our new, conservative analysis finds that the DM lifetime must satisfy $\tau\gtrsim 10^{27}\,{\rm s}\times (m_{\chi}/\rm MeV)^{-1}$ for DM masses $m_{\chi}=0.054-3.6$ MeV. For MeV-scale DM that annihilates into photons INTEGRAL sets the strongest constraints to date, whereas for annihilations to electron-positron pairs, INTEGRAL only improves upon current limits when assuming $p$-wave annihilation. Second, we target ultralight primordial black holes (PBHs) through their Hawking radiation. This makes them appear as decaying DM with a photon spectrum peaking at $E\approx 5/(8\pi G M_{\rm PBH})$, for a PBH of mass $M_{\rm PBH}$. We use the INTEGRAL data to demonstrate that PBHs with masses less than 2 $\times 10^{17}$ g cannot comprise all of the DM, setting the tightest bound to date on ultralight PBHs.

[3]  arXiv:2004.00628 [pdf, other]

Title: Massive donors in interacting binaries: impact of metallicity

Authors: Jakub Klencki, Gijs Nelemans, Alina Istrate, Onno Pols

Comments: 15 pages, 8 figures (+ 4 pages, 4 fig. appendix), accepted for publication in A&A

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

Metallicity is known to significantly affect the radial expansion of a massive star: the lower the metallicity the more compact the star, especially during its post-MS evolution. We study the impact of this effect in the context of binary evolution. Using the stellar-evolution code MESA, we compute evolutionary tracks of stars at different metallicities, exploring variations of factors known to affect the radial expansion (eg. semiconvection, overshooting, rotation). We find observational support for evolution in which already at metallicity $0.2Z_{\odot}$ massive stars stay relatively compact during the Hertzprung-Gap phase (HG) and most of their expansion happens during core-helium burning (CHeB). Consequently, we show that metallicity has a strong influence on the type of mass transfer evolution in binary systems. At solar metallicity a case-B mass transfer is initiated shortly after the end of MS and a giant donor is almost always a rapidly-expanding HG star. At lower metallicity the parameter space for mass transfer from a more evolved CHeB star increases dramatically. This means that envelope stripping and formation of helium stars in low metallicity environments happens later during the evolution of the donor, implying a much shorter duration of the Wolf-Rayet phase (even by an order of magnitude) and higher final core masses. This metallicity effect is independent of the impact of metallicity-dependent stellar winds. At very low metallicities a significant fraction of massive stars engage in their first episode of mass transfer very late into their evolution, when they already have a well developed CO core. The remaining lifetime ($< 10^4$ yr) is unlikely to be enough to strip the entire H-rich envelope. We also briefly discuss the extremely small parameter space for mass transfer from massive convective-envelope donors in the context of binary black hole merger formation.

[4]  arXiv:2004.00632 [pdf, other]

Title: X-ray annual modulation observed by XMM-Newton and Axion Quark Nugget Dark Matter

Authors: Shuailiang Ge, Hikari Rachmat, Md Shahriar Rahim Siddiqui, Ludovic Van Waerbeke, Ariel Zhitnitsky

Comments: 16 pages, 13 figures, submitted to MNRAS

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

The XMM-Newton observatory shows evidence with an $11 \sigma$ confidence level for seasonal variation of the X-ray background in the near-Earth environment in the 2-6 keV energy range (Fraser et al. 2014). The interpretation of the seasonal variation given in Fraser et al. 2014 was based on the assumption that solar axions convert to X-rays in the Earth's magnetic field. There are many problems with this interpretation, since the axion-photon conversion must preserve the directionality of the incoming solar axion. At the same time, this direction is avoided by the observations because the XMM-Newton's operations exclude pointing at the Sun and at the Earth. The observed seasonal variation suggests that the signal could have a dark matter origin, since it is very difficult to explain with conventional astrophysical sources. We propose an alternative explanation which involves the so-called Axion Quark Nugget (AQN) dark matter model. In our proposal, dark matter is made of AQNs, which can cross the Earth and emit high energy photons at their exit. We show that the emitted intensity and spectrum is consistent with Fraser et al. 2014, and that our calculation is not sensitive to the specific details of the model. We also find that our proposal predicts a large seasonal variation, on the level of 20-25%, much larger than conventional dark matter models (1-10%). Since the AQN emission spectrum extends up to $\sim$100 keV, well beyond the keV sensitivity of XMM-Newton, we predict the AQN contribution to the hard X-ray and $\gamma$-ray backgrounds in the Earth's environment. The Gamma-Ray Burst Monitor instrument (GBM), aboard the Fermi telescope, is sensitive to the 8 keV-40 MeV energy band. We suggest that the multi-year archival data from the GBM could be used to search for a seasonal variation in the near-Earth environment up to 100 keV as a future test of the AQN framework.

[5]  arXiv:2004.00633 [pdf, other]

Title: Deflection of the hypervelocity stars by the dance of the Milky Way and Large Magellanic Cloud

Authors: Douglas Boubert, Denis Erkal, Alessia Gualandris

Comments: 12 pages, submitted to MNRAS

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

Stars slingshotted by the supermassive black hole at the Galactic centre will escape the Milky Way so quickly that their trajectories will be almost straight lines. Previous works have shown how these `hypervelocity stars' are subsequently deflected by the gravitational field of the Milky Way and the Large Magellanic Cloud (LMC), but have neglected to account for the reflex motion of the Milky Way in response to the fly by of the LMC. A consequence of this motion is that the hypervelocity stars we see on the outskirts of the Milky Way today were ejected from where the Milky Way centre was hundreds of millions of years ago. This change in perspective causes large apparent deflections in the trajectories of the hypervelocity stars, which are of the same order as the deflections caused by the gravitational force of the Milky Way and LMC. We quantify these deflections by simulating the production of hypervelocity stars in an isolated Milky Way (with a spherical or flattened dark matter halo), in a fixed-in-place Milky Way with a passing LMC, and in a Milky Way which responds to the passage of the LMC. The proper motion precision necessary to measure these deflections will be possible with the combination of Gaia with the proposed GaiaNIR successor mission, and these measurements will unlock the hypervelocity stars as probes of the shape of the Milky Way, the mass of the LMC, and of the dance of these two galaxies.

[6]  arXiv:2004.00634 [pdf, other]

Title: Survey of Gravitationally-lensed Objects in HSC Imaging (SuGOHI). VI. Crowdsourced lens finding with Space Warps

Authors: Alessandro Sonnenfeld (1 and 2), Aprajita Verma (3), Anupreeta More (2 and 4), Campbell Allen (3), Elisabeth Beaten (5), James H. H. Chan (6), Roger Hutchings (3), Anton T. Jaelani (7 and 8), Chien-Hsiu Lee (9), Christine Macmillan (5), Philip J. Marshall (10), James O' Donnell (3), Masamune Oguri (2, 11 and 12), Cristian E. Rusu (13), Marten Veldthuis (3), Kenneth C. Wong (2 and 14), Claude Cornen (5), Christopher Davis (10), Adam McMaster (3), Laura Trouille (15), Chris Lintott (3), Grant Miller (3) ((1) Leiden Observatory, (2) Kavli IPMU, (3) University of Oxford, (4) IUCAA, (5) Zooniverse, (6) EPFL, (7) Kindai University, (8) Institut Teknologi Bandung, (9) NAOA, (10) KIPAC, (11) University of Tokyo, (12) Research Center for the Early Universe, (13) Subaru Telescope, (14) NAOJ, (15) Adler Planetarium)

Comments: Submitted to Astronomy & Astrophysics. 19 pages, 11 figures

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

Strong lenses are extremely useful probes of the distribution of matter on galaxy and cluster scales at cosmological distances, but are rare and difficult to find. The number of currently known lenses is on the order of 1,000. We wish to use crowdsourcing to carry out a lens search targeting massive galaxies selected from over 442 square degrees of photometric data from the Hyper Suprime-Cam (HSC) survey. We selected a sample of $\sim300,000$ galaxies with photometric redshifts in the range $0.2 < z_{phot} < 1.2$ and photometrically inferred stellar masses $\log{M_*} > 11.2$. We crowdsourced lens finding on this sample of galaxies on the Zooniverse platform, as part of the Space Warps project. The sample was complemented by a large set of simulated lenses and visually selected non-lenses, for training purposes. Nearly 6,000 citizen volunteers participated in the experiment. In parallel, we used YattaLens, an automated lens finding algorithm, to look for lenses in the same sample of galaxies. Based on a statistical analysis of classification data from the volunteers, we selected a sample of the most promising $\sim1,500$ candidates which we then visually inspected: half of them turned out to be possible (grade C) lenses or better. Including lenses found by YattaLens or serendipitously noticed in the discussion section of the Space Warps website, we were able to find 14 definite lenses, 129 probable lenses and 581 possible lenses. YattaLens found half the number of lenses discovered via crowdsourcing. Crowdsourcing is able to produce samples of lens candidates with high completeness and purity, compared to currently available automated algorithms. A hybrid approach, in which the visual inspection of samples of lens candidates pre-selected by discovery algorithms and/or coupled to machine learning is crowdsourced, will be a viable option for lens finding in the 2020s.

[7]  arXiv:2004.00637 [pdf, other]

Title: WASP-4 is Accelerating Toward the Earth

Authors: L. G. Bouma, J. N. Winn, A. W. Howard, S. B. Howell, H. Isaacson, H. Knutson, R. A. Matson

Comments: ApJL accepted

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

The orbital period of the hot Jupiter WASP-4b appears to be decreasing at a rate of $-8.64 \pm 1.26$ msec/yr, based on transit-timing measurements spanning 12 years. Proposed explanations for the period change include tidal orbital decay, apsidal precession, and acceleration of the system along the line of sight. To investigate further, we performed new radial velocity measurements and speckle imaging of WASP-4. The radial-velocity data show that the system is accelerating towards the Sun at a rate of $-0.0422\pm 0.0028$ m/s/day. The associated Doppler effect should cause the apparent period to shrink at a rate of $-5.94 \pm 0.39$ msec/yr, comparable to the observed rate. Thus, the observed change in the transit period is mostly or entirely produced by the line-of-sight acceleration of the system. This acceleration is probably caused by a wide-orbiting companion of mass 10-300$\,M_{\rm Jup}$ and orbital distance 10-100$\,$AU, based on the magnitude of the radial-velocity trend and the non-detection of any companion in the speckle images. We expect that the orbital periods of 1 out of 3 hot Jupiters will change at rates similar to WASP-4b, based on the hot-Jupiter companion statistics of Knutson et al. (2014). Continued radial velocity monitoring of hot Jupiters is therefore essential to distinguish the effects of tidal orbital decay or apsidal precession from line-of-sight acceleration.

[8]  arXiv:2004.00641 [pdf, other]

Title: A 1201 s Orbital Period Detached Binary: the First Double Helium Core White Dwarf LISA Verification Binary

Authors: Warren R. Brown (1), Mukremin Kilic (2), A. Bedard (3), Alekzander Kosakowski (2), P. Bergeron (3) ((1) SAO, (2) OU, (3) UMontreal)

Comments: 7 pages, 4 figures, ApJ Letters accepted

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

We report the discovery of a 1201 s orbital period binary, the third shortest-period detached binary known. SDSS J232230.20+050942.06 contains two He-core white dwarfs orbiting with a 27 deg inclination. Located 0.76 kpc from the Sun, the binary has an estimated LISA 4-yr signal-to-noise ratio of 40. J2322+0509 is the first He+He white dwarf LISA verification binary, a source class that is predicted to account for one-third of resolved LISA ultra-compact binary detections.

[9]  arXiv:2004.00644 [pdf, other]

Title: FRB Coherent Emission from Decay of Alfven Waves

Authors: Pawan Kumar, Z. Bosnjak

Comments: To appear in MNRAS in April 2020; 11 pages 2 figures

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

We present a model for FRBs where a large amplitude Alfven wave packet is launched by a disturbance near the surface of a magnetar, and a substantial fraction of the wave energy is converted to coherent radio waves at a distance of a few tens of neutron star radii. The wave amplitude at the magnetar surface should be about 1011G in order to produce a FRB of isotropic luminosity 10$^{44}$ erg s$^{-1}$. An electric current along the static magnetic field is required by Alfven waves with nonzero component of transverse wave-vector. The current is supplied by counter-streaming electron-positron pairs, which have to move at nearly the speed of light at larger radii as the plasma density decreases with distance from the magnetar surface. The counter-streaming pairs are subject to two-stream instability which leads to the formation of particle bunches of size of order $c/\omega_p$; where $\omega_p$ is plasma frequency. A strong electric field develops along the static magnetic field when the wave packet arrives at a radius where electron-positron density is insufficient to supply the current required by the wave. The electric field accelerates particle bunches along the curved magnetic field lines, and that produces the coherent FRB radiation. We provide a number of predictions of this model.

[10]  arXiv:2004.00645 [pdf, other]

Title: Radiation Forces Constrain the FRB Mechanism

Authors: Pawan Kumar, Wenbin Lu

Comments: 12 pages, 3 figures, to appear in MNRAS, April 2020

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

We provide constraints on Fast Radio Burst (FRB) models by careful considerations of radiation forces associated with these powerful transients. We find that the induced-Compton scatterings of the coherent radiation by electrons/positrons accelerate particles to very large Lorentz factors (LF) in and around the source of this radiation. This severely restricts those models for FRBs that invoke relativistic shocks and maser type instabilities at distances less than about $10^{13}$ cm of the neutron star. Radiation traveling upstream, in these models, forces particles to move away from the shock with a LF larger than the LF of the shock front. This suspends the photon generation process after it has been operating for less than ~0.1 ms (observer frame duration). We show that masers operating in shocks at distances larger than $10^{13}$ cm cannot simultaneously account for the burst duration of 1 ms or more and the observed ~1 GHz frequencies of FRBs without requiring an excessive energy budget ($10^{46}$ erg); the energy is not calculated by imposing any efficiency consideration, or other details, for the maser mechanism, but is entirely the result of ensuring that particle acceleration by induced-Compton forces upstream of the shock front does not choke off the maser process. For the source to operate more or less continuously for a few ms, it should be embedded in a strong magnetic field - cyclotron frequency $\gg$ wave frequency - so that radiation forces do not disperse the plasma and shut-off the engine.

[11]  arXiv:2004.00647 [pdf, other]

Title: Maps of the number of HI clouds along the line of sight at high galactic latitude

Authors: G. V. Panopoulou, D. Lenz

Comments: 28 pages (including appendices), 19 figures, submitted to AAS journals, comments welcome

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

Characterizing the structure of the Galactic Interstellar Medium (ISM) in three dimensions is of high importance for accurate modeling of dust emission as a foreground to the Cosmic Microwave Background (CMB). At high Galactic latitude, where the total dust content is low, accurate maps of the 3D structure of the ISM are lacking. We develop a method to quantify the complexity of the distribution of dust along the line of sight with the use of HI line emission. The method relies on a Gaussian decomposition of the HI spectra to disentangle the emission from overlapping components in velocity. We use this information to create maps of the number of clouds along the line of sight. We apply the method to: (a) the high-galactic latitude sky and (b) the region targeted by the BICEP/Keck experiment. In the North Galactic Cap pixels are occupied by 3 clouds on average, while in the South the number falls to 2.5. The statistics of the number of clouds are affected by Intermediate-Velocity Clouds (IVCs), primarily in the North. The presence of IVCs results in detectable features in the dust emission measured by \textit{Planck}. We investigate the complexity of HI spectra in the BICEP/Keck region and find evidence for the existence of multiple components along the line of sight. The data and software are made publicly available, and can be used to inform CMB foreground modeling and 3D dust mapping.

[12]  arXiv:2004.00649 [pdf, other]

Title: A Triple Rollover: A third multiply-imaged source at z~6 behind the Jackpot gravitational lens

Authors: Thomas E. Collett, Russell J. Smith

Comments: 7 pages, submitted to MNRAS. The authors contributed equally to this work

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

Using deep integral-field spectroscopy with MUSE, we have identified a doubly-imaged Ly alpha source at redshift 5.975 behind the z=0.222 lens galaxy J0946+1006 ('the Jackpot'). The source separation implies an Einstein radius of ~2.5 arcsec. Combined with the two previously-known Einstein rings in this lens (radii 1.4 arcsec at z = 0.609 and 2.1 arcsec at z ~ 2.4), this system is now a unique galaxy-scale triple-source-plane lens. We show that existing lensing models for J0946+1006 successfully map the two new observed images to a common point on the z=5.975 source plane. The new source will provide further constraints on the mass distribution in the lens and in the two previously known sources. The third source also probes two new distance scaling factors which are sensitive to the cosmological parameters of the Universe. We show that detection of a new multiply imaged emission-line source is not unexpected in observations of this depth; similar data for other known lenses should reveal a larger sample of multiple-image-plane systems for cosmography and other applications.

[13]  arXiv:2004.00650 [pdf, other]

Title: The mass gap, the spin gap, and the origin of merging binary black holes

Authors: Vishal Baibhav, Davide Gerosa, Emanuele Berti, Kaze W. K. Wong, Thomas Helfer, Matthew Mould

Comments: 21 pages, 14 figures

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

Two of the dominant channels to produce the black-hole binary mergers observed by LIGO and Virgo are believed to be the isolated evolution of stellar binaries in the field and dynamical formation in star clusters. Their relative efficiency can be characterized by a "mixing fraction." Pair instabilities prevent stellar collapse from generating black holes more massive than about $45 M_\odot$. This "mass gap" only applies to the field formation scenario, and it can be filled by repeated mergers in clusters. A similar reasoning applies to the binary's effective spin. If black holes are born slowly rotating, the high-spin portion of the parameter space (the "spin gap") can only be populated by black hole binaries that were assembled dynamically. Using a semianalytical cluster model, we show that future gravitational-wave events in either the mass gap, the spin gap, or both can be leveraged to infer the mixing fraction between the field and cluster formation channels.

[14]  arXiv:2004.00656 [pdf, other]

Title: Optimized statistical approach for combining multi-messenger data for neutron star equation of state inference

Authors: Carolyn Raithel, Feryal Ozel, Dimitrios Psaltis

Comments: Submitted to ApJ

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

The neutron star equation of state (EOS) is now being constrained from a diverse set of multi-messenger data, including gravitational waves from binary neutron star mergers, X-ray observations of the neutron star radius, and many types of laboratory nuclear experiments. These measurements are typically mapped to a common domain -- either to a corresponding radius or to a parametrized EOS using a Bayesian inference scheme -- for comparison with one another. We explore here the statistical biases that can arise when such multi-messenger data are mapped to a common domain for comparison. We find that placing Bayesian priors individually in each domain of measurement can transform to biased constraints in the domain of comparison. Using the first two binary neutron star mergers as an example, we show that a uniform prior in the tidal deformability can produce artificial evidence for large radii, which the data do not support. We present a new prescription for defining Bayesian priors in any domain of measurement, that will allow for minimally-biased constraints in the domain of comparison. Finally, using this new prescription, we provide a status update on multi-messenger EOS constraints on the neutron star radius.

[15]  arXiv:2004.00664 [pdf, other]

Title: Is superorbital modulation in SMC X-1 caused by absorption in warped precessing accretion disc?

Authors: Pragati Pradhan, Chandreyee Maitra, Biswajit Paul

Comments: 14 pages, 6 figures, 4 tables; accepted for publication in ApJ

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

We present a broadband spectral-timing analysis of SMC X-1 at different intensity states of its super-orbital variation using 10 Suzaku and 6 NuSTAR observations. The spectrum in all the states can be described by an absorbed powerlaw with a high energy cutoff and a black-body component along with an iron emission line. Compared to other supergiant HMXBs, the Fe K$\alpha$ line equivalent width is low in SMC X-1 - from less than 10 eV in high state to up to $\sim$ 270 eV in the low states. The spectral shape is dependent on flux with the hard X-ray spectrum steepening with increasing flux. We also report a highly variable normalisation of the power-law component across these 16 super-orbital states. Pulsations in the hard X-rays for both the instruments were detected in all but two observations. The pulse profiles are near sinusoidal with two peaks and the relative intensity of the second peak decreasing with decreasing luminosity. These findings suggest that the super-orbital modulation in SMC X-1 is not caused by absorption in precessing warped accretion disc alone and there are intrinsic changes in X-rays emanating from the neutron star at different super-orbital states. We also note a putative cyclotron line at $\sim$ 50 keV in the \nustar~spectra of three bright states indicating a possible magnetic field of $\sim$ 4.2 $\times$ 10$^{12}$ G. Finally, with the new pulse period measurements reported here, the time base for the secular spin-up of SMC X-1 is increased by thirteen years and the complete pulse period history shows a sudden change in the spin-up trend around 1995.

[16]  arXiv:2004.00672 [pdf, other]

Title: Generating primordial features at large scales in two field models of inflation

Authors: Matteo Braglia, Dhiraj Kumar Hazra, Lakshmanan Sriramkumar, Fabio Finelli

Comments: 25 pages, 9 figures

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

We investigate the generation of features at large scales in the primordial power spectrum (PPS) when inflation is driven by two scalar fields. In canonical single field models of inflation, these features are often generated due to deviations from the slow-roll regime. While deviations from slow-roll can be naturally achieved in two field models due to a sharp turn in the trajectory in the field space, features at the largest scales of the types suggested by CMB temperature anisotropies are more difficult to achieve in models involving two canonical scalar fields due to the presence of isocurvature fluctuations. We show instead that a coupling between the kinetic terms of the scalar fields can easily produce such features. We discuss models whose theoretical predictions are consistent with current observations and highlight the implications of our results.

[17]  arXiv:2004.00676 [pdf, ps, other]

Title: Swift observations of Mrk\,421 in selected epochs. iii. Extreme x-ray timing/spectral properties and multiwavelength lognormality in 2015\,December--2018\,April

Authors: B. Kapanadze, A. Gurchumelia, D. Dorner, S. Vercellone, P. Romano, P. Hughes, M. Aller, H. Aller, O. Kharshiladze

Comments: Accept

Journal-ref: The Astrophysical Journal, 2020

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

We present the results from the timing and spectral study of Mrk\,421 based mainly on the \emph{Swift} data in the X-ray energy range obtained during the time interval 2015\,December--2018\,April. The most extreme X-ray flaring activity on the long-term, daily and intraday timescales was observed during the 2-month period which started in 2017\,December when the 0.3--10\,keV flux exceeded a level of 5$\times$10$^{-9}$erg\,cm$^{-2}$s$^{-1}$, recorded only twice previously. While the TeV-band and X-ray variabilities mostly were correlated, the source often varied in a complex manner in the MeV--GeV and radio--UV energy ranges, indicating that the multifrequency emission of Mrk\,421 could not be always generated in a single zone. The longer-term flares at X-rays and $\gamma$-rays showed a lognormal character, possibly indicating a variability imprint of the accretion disk onto the jet. A vast majority of the 0.3--10\,keV spectra were consistent with the log-parabolic model, showing relatively low spectral curvature and correlations between the different spectral parameters, predicted in the case of the first and second-order Fermi processes. The position of the synchrotron spectral energy distribution (SED) peak showed an extreme variability on diverse timescales between the energies $E_{\rm p}$$<$0.1\,keV and $E_{\rm p}$$>$15\,keV, with 15\% of the spectra peaking at hard X-rays and was related to the peak height as $S_{\rm p}$$\varpropto$$E^{\alpha}_{\rm p}$ with $\alpha$$\sim$0.6, which is expected for the transition from Kraichnan-type turbulence into the \textquotedblleft hard-sphere\textquotedblright~ one. The 0.3--300\,GeV spectra showed the features of the hadronic contribution, jet-star interaction and upscatter in the Klein-Nishina regime in different time intervals.

[18]  arXiv:2004.00678 [pdf, ps, other]

Title: Tight Constraints on the Excess Radio Background at $z = 9.1$ from LOFAR

Authors: R. Mondal, A. Fialkov, C. Fling, I.T. Iliev, R. Barkana, B. Ciardi, G. Mellema, S. Zaroubi, L.V.E Koopmans, F. G. Mertens, B. K. Gehlot, R. Ghara, A. Ghosh, S. K. Giri, V.N. Pandey

Comments: 13 pages, 6 figures, 2 tables, Comments are welcome

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

The ARCADE2 and LWA1 experiments have claimed an excess over the Cosmic Microwave Background (CMB) at low radio frequencies. If the cosmological high-redshift contribution to this radio background is between 0.1% and 22% of the CMB at $1.42\,$GHz, it could explain the tentative EDGES Low-Band detection of the anomalously deep absorption in the 21-cm signal of neutral hydrogen (Fialkov & Barkana 2019). We use the upper limit on the 21-cm signal from the Epoch of Reionization ($z=9.1$) based on $141\,$hours of observations with LOFAR (Mertens et al. 2020) to evaluate the contribution of the high redshift Universe to the detected radio background. Marginalizing over astrophysical properties of star-forming halos, we find (at 68% C.L.) that the cosmological radio background can be at most 0.7% of the CMB at $1.42\,$GHz. This limit rules out strong contribution of the high-redshift Universe to the ARCADE2 and LWA1 measurements. Even though LOFAR places limit on the extra radio background, excess of $0.1-0.7$% over the CMB (at $1.42\,$GHz) is still allowed and could explain the EDGES Low-Band detection. We also constrain the thermal and ionization state of the gas at $z = 9.1$, and put limits on the properties of the first star-forming objects. We find that, in agreement with the limits from EDGES High-Band data, LOFAR data disfavour scenarios with inefficient X-ray sources and cases where the Universe was ionized by massive halos only.

[19]  arXiv:2004.00680 [pdf, other]

Title: Mergers Do Trigger AGNs out to z $\sim$ 0.6

Authors: F. Gao, L. Wang, W. J. Pearson, Y. A. Gordon, B. W. Holwerda, A. M. Hopkins, M. J. I. Brown, J. Bland-Hawthorn, M. S. Owers

Comments: 18 pages, accepted for publication in A&A

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

Aims. The fueling and feedback of Active Galactic Nuclei (AGNs) are important in understanding the co-evolution between black holes and host galaxies. Mergers are thought to have the capability to bring gas inwards and ignite nuclear activity, especially for more powerful AGNs. However, there is still significant ongoing debate on whether mergers can trigger AGNs and, if they do, whether mergers are a significant triggering mechanism. Methods. We select a low-redshift ($0.005<z<0.1$) sample from the Sloan Digital Sky Survey (SDSS) and a high-redshift ($0 < z < 0.6$) sample from the Galaxy And Mass Assembly (GAMA) survey. We take advantage of the convolutional neural network technique to identify mergers. We use mid-infrared (MIR) color cut and optical emission line diagnostics to classify AGNs. We also include Low Excitation Radio Galaxies (LERGs) to investigate the connection between mergers and low accretion rate AGNs. Results. We find that AGNs are more likely to be found in mergers than non-mergers, with an AGN excess up to $1.81\pm{0.16}$, suggesting that mergers can trigger AGNs. We also find the fraction of mergers in AGNs is higher than that in non-AGN controls, for both MIR and optically selected AGNs, as well as LERGs, with values between $16.40\pm{0.5}\%$ and $39.23\pm{2.10}\%$, implying a non-negligible to potentially significant role of mergers in triggering AGNs. This merger fraction in AGNs increases as stellar mass increases which supports the idea that mergers are more important for triggering AGNs in more massive galaxies. In terms of merger fraction as a function of AGN power we find a positive trend for MIR selected AGNs and a complex trend for optically selected AGNs, which we interpret under an evolutionary scenario proposed by previous studies. In addition, obscured MIR selected AGNs are more likely to be hosted in mergers than unobscured MIR selected AGNs.

[20]  arXiv:2004.00718 [pdf, other]

Title: The properties of inside-out assembled galaxies at $z<0.1$

Authors: Dejene Zewdie, Mirjana Pović, Manuel Aravena, Roberto J. Assef, Asrate Gaulle

Comments: 3 pages, 2 figures, Proceedings paper of the IAU symposium "Nuclear Activity in Galaxies Across Cosmic Time" (Ethiopia) accepted to be published under the Cambridge University Press, eds M. Povi\'c, P. Marziani, J. Masegosa, H. Netzer, S. H. Negu, & S. B. Tessema

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

In this work, we study the properties of galaxies that are showing the inside-out assembly (which we call inside-out assembled galaxies; IOAGs), with the main aim to understand better their properties and morphological transformation. We analysed a sample of galaxies from the Sloan Digital Sky Survey (SDSS) Data Release 8 (DR8), with stellar masses in the range $\log M_{\star}=10.73-11.03$ $M_{\odot{}}$ at $z < 0.1$, and analyze their location in the stellar mass-SFR and the color-stellar mass diagram. We found that IOAGs have different spectroscopic properties, most of them being classified either as AGN or composite. We found that the majority of our sources are located below the main sequence of star formation in the SFR-stellar mass diagram, and in the green valley or red sequence in the color-stellar mass diagram. We argue that IOAGs seem to correspond to the transition area where the galaxies are moving from star-forming to quiescent, and from the blue cloud to the red sequence and/or to recently quenched galaxies.

[21]  arXiv:2004.00727 [pdf]

Title: The Geology and Geophysics of Kuiper Belt Object (486958) Arrokoth

Authors: J.R. Spencer (1), S.A. Stern (1), J.M. Moore (2), H.A. Weaver (3), K.N. Singer (1), C.B. Olkin (1), A.J. Verbiscer (4), W.B. McKinnon (5), J.Wm. Parker (1), R.A. Beyer (6 and 2), J.T. Keane (7), T.R. Lauer (8), S.B. Porter (1), O.L. White (6 and 2), B.J. Buratti (9), M.R. El-Maarry (10 and 11), C.M. Lisse (3), A.H. Parker (1), H.B. Throop (12), S.J. Robbins (1), O.M. Umurhan (2), R.P. Binzel (13), D.T. Britt (14), M.W. Buie (1), A.F. Cheng (3), D.P. Cruikshank (2), H.A. Elliott (15), G.R. Gladstone (15), W.M. Grundy (16 and 17), M.E. Hill (3), M. Horanyi (18), D.E. Jennings (19), J.J. Kavelaars (20), I.R. Linscott (21), D.J. McComas (22), R.L. McNutt (3), S. Protopapa (1), D.C. Reuter (19), P.M. Schenk (23), M.R. Showalter (6), L.A. Young (1), A.M. Zangari (1), A.Y. Abedin (20), C.B. Beddingfield (6), et al. (34 additional authors not shown)

Journal-ref: Science, 367, aay3999 (2020)

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

The Cold Classical Kuiper Belt, a class of small bodies in undisturbed orbits beyond Neptune, are primitive objects preserving information about Solar System formation. The New Horizons spacecraft flew past one of these objects, the 36 km long contact binary (486958) Arrokoth (2014 MU69), in January 2019. Images from the flyby show that Arrokoth has no detectable rings, and no satellites (larger than 180 meters diameter) within a radius of 8000 km, and has a lightly-cratered smooth surface with complex geological features, unlike those on previously visited Solar System bodies. The density of impact craters indicates the surface dates from the formation of the Solar System. The two lobes of the contact binary have closely aligned poles and equators, constraining their accretion mechanism.

[22]  arXiv:2004.00747 [pdf, ps, other]

Title: Self-similar orbit-averaged Fokker-Planck equation for isotropic spherical dense clusters (iii) Application to Galactic globular clusters

Authors: Yuta Ito

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

This is the third paper of a series of our works on the self-similar orbit-averaged Fokker-Planck (OAFP) equation. The first paper shows an accurate spectral solution of the equation for isotropic pre-collape cluster and the second details the physical feature of the model and negative specific heat. Based on the works, the present work applies the solution to observed the structural profiles of Galactic globular clusters. For fitting to the structures, the most fundamental (quasi-)stationary model, the King model, and the variants have shown successful results while they can not apply to clusters just before or after core-collapse phase at the late stage of the relaxation evolution. We aim at establishing an energy-truncated self-similar OAFP model that can apply to clusters at both the early- and late stage of the evolution. This new model fits the structural profiles of at least half of Galactic globular clusters while it also applies to core-collapsed stars with resolved cores. As a main result, we provide the completion rate of core collapse against concentration for the clusters. Also, we show our new model can apply to the globular clusters even at broad radii (0.01$\sim$10 arcminutes). However, due to the nature of polytrope (elongated outer halo) the tidal radius of the model becomes unrealistically large for some clusters. To avoid the issue, we propose an approximated form of the new model. Lastly, we suggest that Milky Way globular clusters with low concentrations have the same spatial structures as stellar polytropes and discuss whether such polytropic globular cluster can exist.

[23]  arXiv:2004.00791 [pdf, ps, other]

Title: Discovery of delayed spin-up behavior following two large glitches in the Crab pulsar, and the statistics of such processes

Authors: M. Y. Ge (1), S. N. Zhang (1,3), F. J. Lu (1), T. P. Li (1,2,3), J. P. Yuan (4,5), X. P. Zheng (6), Y. Huang (1), S. J. Zheng (1), Y. P. Chen (1), Z. Chang (1), Y. L. Tuo (1,3), Q. Cheng (7), C. Güngör (1,8), L. M. Song (1,3), Y. P. Xu (1), X. L. Cao (1), Y. Chen (1), C. Z. Liu (1), S. Zhang (1), J. L. Qu (1,3), Q. C. Bu (1), C. Cai (1), G. Chen (1), L. Chen (9), M. Z. Chen (4), T. X. Chen (1), Y. B. Chen (2), W. Cui (2), W. W. Cui (1), J. K. Deng (2), Y. W. Dong (1), Y. Y. Du (1), M. X. Fu (2), G. H. Gao (1,3), H. Gao (1,3), M. Gao (1), Y. D. Gu (1), J. Guan (1), C. C. Guo (1,3), D. W. Han (1), L. F. Hao (10), J. Huo (1), S. M. Jia (1), L. H. Jiang (1), W. C. Jiang (1), C. J. Jin (11), J. Jin (1), Y. J. Jin (15), L. D. Kong (1,3), B. Li (1), D. Li (11), C. K. Li (1), G. Li (1), et al. (83 additional authors not shown)

Comments: 25 pages, 8 figures

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

Glitches correspond to sudden jumps of rotation frequency ($\nu$) and its derivative ($\dot{\nu}$) of pulsars, the origin of which remains not well understood yet, partly because the jump processes of most glitches are not well time-resolved. There are three large glitches of the Crab pulsar, detected in 1989, 1996 and 2017, which were found to have delayed spin-up processes before the normal recovery processes. Here we report two additional glitches of the Crab pulsar occurred in 2004 and 2011 for which we discovered delayed spin up processes, and present refined parameters of the largest glitch occurred in 2017. The initial rising time of the glitch is determined as $<0.48$ hour. We also carried out a statistical study of these five glitches with observed spin-up processes. The two glitches occurred in 2004 and 2011 have delayed spin-up time scales ($\tau_{1}$) of $1.7\pm0.8$\,days and $1.6\pm0.4$\,days, respectively. We find that the $\Delta{\nu}$ vs. $|\Delta{\dot\nu}|$ relation of these five glitches is similar to those with no detected delayed spin-up process, indicating that they are similar to the others in nature except that they have larger amplitudes. For these five glitches, the amplitudes of the delayed spin-up process ($|\Delta{\nu}_{\rm d1}|$) and recovery process ($\Delta{\nu}_{\rm d2}$), their time scales ($\tau_{1}$, $\tau_{2}$), and permanent changes in spin frequency ($\Delta{\nu}_{\rm p}$) and total frequency step ($\Delta{\nu}_{\rm g}$) have positive correlations. From these correlations, we suggest that the delayed spin-up processes are common for all glitches, but are too short and thus difficult to be detected for most glitches.

[24]  arXiv:2004.00815 [pdf, other]

Title: Quantifying the effect of field variance on the H$α$ luminosity function with the New Numerical Galaxy Catalogue ($ν^2$GC)

Authors: Kazuyuki Ogura, Masahiro Nagashima, Rhythm Shimakawa, Masao Hayashi, Masakazu A. R. Kobayashi, Taira Oogi, Tomoaki Ishiyama, Yusei Koyama, Ryu Makiya, Katsuya Okoshi, Masato Onodera, Hikari Shirakata

Comments: 13 pages, 11 figures, accepted for publication in the ApJ

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

We construct a model of H$\alpha$ emitters (HAEs) based on a semi-analytic galaxy formation model, the New Numerical Galaxy Catalog ($\nu^2$GC). In this paper, we report our estimate for the field variance of the HAE distribution. By calculating the H$\alpha$ luminosity from the star-formation rate of galaxies, our model well reproduces the observed H$\alpha$ luminosity function (LF) at $z=0.4$. The large volume of the $\nu^2$GC makes it possible to examine the spatial distribution of HAEs over a region of (411.8 Mpc)$^3$ in the comoving scale. The surface number density of $z=0.4$ HAEs with $L_{\rm H\alpha} \geq 10^{40}$ erg s$^{-1}$ is 308.9 deg$^{-2}$. We have confirmed that the HAE is a useful tracer for the large-scale structure of the Universe because of their significant overdensity ($>$ 5$\sigma$) at clusters and the filamentary structures. The H$\alpha$ LFs within a survey area of $\sim$2 deg$^2$ (typical for previous observational studies) show a significant field variance up to $\sim$1 dex. Based on our model, one can estimate the variance on the H$\alpha$ LFs within given survey areas.

[25]  arXiv:2004.00836 [pdf, other]

Title: The effect of hydrodynamics alone on the subhalo population in a $Λ$CDM rich cluster sized dark matter halo

Authors: Junyi Jia, Liang Gao, Yan Qu

Comments: 8 pages, 6 figres

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

We perform a set of non-radiative hydro-dynamical (NHD) simulations of a rich cluster sized dark matter halo from the Phoenix project with 3 different numerical resolutions, to investigate the effect of hydrodynamics alone on the subhalo population in the halo. Compared to dark matter only (DMO) simulations of the same halo, subhaloes are less abundant for relatively massive subhaloes ($M_{sub} > 2.5 \times 10^9h^{-1}M_{\odot}$, or $V_{max} > 70 kms^{-1}$) but more abundant for less massive subhaloes in the NHD simulations. This results in different shapes in the subhalo mass/$V_{max}$ function in two different sets of simulations. At given subhalo mass, the subhaloes less massive than $10^{10} h^{-1}M_{\odot}$ have larger $V_{max}$ in the NHD than DMO simulations, while $V_{max}$ is similar for the subhaloes more massive than the mass value. This is mainly because the progenitors of present day low mass subhaloes have larger concentration parameters in the NHD than DMO simulations. The survival number fraction of the accreted low mass progenitors of the main halo at redshift 2 is about 50 percent higher in the NHD than DMO simulations.

[26]  arXiv:2004.00846 [pdf, other]

Title: Equation of state constraints from the threshold binary mass for prompt collapse of neutron star mergers

Authors: Andreas Bauswein, Sebastian Blacker, Vimal Vijayan, Nikolaos Stergioulas, Katerina Chatziioannou, James A. Clark, Niels-Uwe F. Bastian, David B. Blaschke, Mateusz Cierniak, Tobias Fischer

Comments: 8 pages, 2 figures, 1 table

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

Using hydrodynamical simulations for a large set of high-density matter equations of state (EoSs) we systematically determine the threshold mass M_thres for prompt black-hole formation in equal-mass and asymmetric neutron star (NS) mergers. We devise the so far most direct, general and accurate method to determine the unknown maximum mass of nonrotating NSs from merger observations revealing M_thres. Considering hybrid EoSs with hadron-quark phase transition, we identify a new, observable signature of quark matter in NS mergers. Furthermore, our findings have direct applications in gravitational wave searches, kilonova interpretations and multi-messenger constraints on NS properties.

[27]  arXiv:2004.00847 [pdf, other]

Title: FLASH Early Science -- Discovery of an intervening HI 21-cm absorber from an ASKAP survey of the GAMA 23 field

Authors: J. R. Allison, E. M. Sadler, S. Bellstedt, L. J. M. Davies, S. P. Driver, S. L. Ellison, M. Huynh, A. D. Kapinska, E. K. Mahony, V. A. Moss, A. S. G. Robotham, M. T. Whiting, S. J. Curran, J. Darling, A. W. Hotan, R. W. Hunstead, B. S. Koribalski, C. D. P. Lagos, M. Pettini, K. A. Pimbblet, M. A. Voronkov

Comments: 15 pages, 12 figures, accepted for publication in MNRAS

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

We present early science results from the First Large Absorption Survey in HI (FLASH), a spectroscopically blind survey for 21-cm absorption lines in cold hydrogen HI gas at cosmological distances using the Australian Square Kilometre Array Pathfinder (ASKAP). We have searched for HI absorption towards 1253 radio sources in the GAMA 23 field, covering redshifts between $z = 0.34$ and $0.79$ over a sky area of approximately 50 square degrees. In a purely blind search we did not obtain any detections of 21-cm absorbers above our reliability threshold. Assuming a fiducial value for the HI spin temperature of $T_{\rm spin}$ = 100 K and source covering fraction $c_{\rm f} = 1$, the total comoving absorption path length sensitive to all Damped Lyman-$\alpha$ Absorbers (DLAs; $N_{\rm HI} \geq 2 \times 10^{20}$ cm$^{-2}$) is $\Delta{X} = 6.6 \pm 0.3$ ($\Delta{z} = 3.7 \pm 0.2$) and super-DLAs ($N_{\rm HI} \geq 2 \times 10^{21}$ cm$^{-2}$) is $\Delta{X} = 111 \pm 6$ ($\Delta{z} = 63 \pm 3$). We estimate upper limits on the HI column density frequency distribution function that are consistent with measurements from prior surveys for redshifted optical DLAs, and nearby 21-cm emission and absorption. By cross matching our sample of radio sources with optical spectroscopic identifications of galaxies in the GAMA 23 field, we were able to detect 21-cm absorption at $z = 0.3562$ towards NVSS J224500$-$343030, with a column density of $N_{\rm HI} = (1.2 \pm 0.1) \times 10^{20} (T_{\rm spin}/100~\mathrm{K})$ cm$^{-2}$. The absorber is associated with GAMA J22450.05$-$343031.7, a massive early-type galaxy at an impact parameter of 17 kpc with respect to the radio source and which may contain a massive ($M_{\rm HI} \gtrsim 3 \times 10^{9}$ M$_{\odot}$) gas disc. Such gas-rich early types are rare, but have been detected in the nearby Universe.

[28]  arXiv:2004.00848 [pdf, other]

Title: Probing the magnetospheric accretion region of the young pre-transitional disk system DoAr 44 using VLTI/GRAVITY

Authors: J. Bouvier, K. Perraut, J.-B. Le Bouquin, G. Duvert, C. Dougados, W. Brandner, M. Benisty, J.-P. Berger, E. Alécian

Comments: Astronomy & Astrophysics, in press, 8 pages, 3 figures

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

Young stellar objects are thought to accrete material from their circumstellar disks through their strong stellar magnetospheres. We aim to directly probe the magnetospheric accretion region on a scale of a few 0.01 au in a young stellar system using long-baseline optical interferometry. We observed the pre-transitional disk system DoAr 44 with VLTI/GRAVITY on two consecutive nights in the K-band. We computed interferometric visibilities and phases in the continuum and in the BrG line in order to constrain the extent and geometry of the emitting regions. We resolve the continuum emission of the inner dusty disk and measure a half-flux radius of 0.14 au. We derive the inclination and position angle of the inner disk, which provides direct evidence that the inner and outer disks are misaligned in this pre-transitional system. This may account for the shadows previously detected in the outer disk. We show that BrG emission arises from an even more compact region than the inner disk, with an upper limit of 0.047 au (5 Rstar). Differential phase measurements between the BrG line and the continuum allow us to measure the astrometric displacement of the BrG line-emitting region relative to the continuum on a scale of a few tens of microarcsec, corresponding to a fraction of the stellar radius. Our results can be accounted for by a simple geometric model where the BrG line emission arises from a compact region interior to the inner disk edge, on a scale of a few stellar radii, fully consistent with the concept of magnetospheric accretion process in low-mass young stellar systems.

[29]  arXiv:2004.00863 [pdf, other]

Title: First Structure Formation under the Influence of Gas-Dark Matter Streaming Velocity and Density: Impact of the Baryons-trace-dark matter Approximation

Authors: Hyunbae Park, Kyungjin Ahn, Naoki Yoshida, Shingo Hirano

Comments: Submitted to ApJ

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

The impact of the streaming motion between gas and dark matter on the first structure formation has been actively explored by recent studies. Here we investigate how much the key results are affected by two approximations made in many of those studies. One is to implement the streaming motion by accounting for only the relative velocity between baryons and dark matter while assuming "baryons trace dark matter" spatially at the initial conditions of the simulation. This assumption neglects the impact on the gas density taking place before the initialization. In our simulation initialized at $z=200$, this approximation overestimates the gas power spectrum up to 30\% at $k\approx10^2~h~\mbox{Mpc}^{-1}$ at $z=20$. However, the halo mass function and the gas fraction in halos are minimally affected. The other approximation is to artificially amplify the density/velocity fluctuations in a cosmic mean density volume at the initialization to simulate the first minihalos. This approximation gives a head start to the halo growth and the subsequent growth rate is as fast as in the mean density. The growth in actual overdensity, however, is accelerated gradually in time. For example, increasing $\sigma_8$ by 50\% effectively transforms $z\rightarrow\sqrt{1.5}z$ in the halo mass growth history while in 2-$\sigma$ overdensity the acceleration is described by $z\rightarrow{z}+4.8$. Halos in the former case are more grown than in the latter before $z\approx27$ and vice versa after. The gas fraction in halo remains unchanged by this second approximation as well, suggesting that those approximations do {\it{not}} bias the PopIII star-formation rate significantly.

[30]  arXiv:2004.00864 [pdf, other]

Title: Local gravity test of unified models of inflation and dark energy in $f(R)$ gravity

Authors: Mai Yashiki, Nobuyuki Sakai, Ryo Saito

Comments: 11 pages, 12 figures

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

We study local-gravity tests on unified models of inflation and dark energy in $f(R)$ gravity. In this paper, we consider three unified models, which are combination of the known dark energy models and the same inflationary term. During inflation, all unified models reduce to the model $f(R)=R + \alpha R^n$, which is a generalization of the $R^2$ inflation model proposed by Starobinsky. From the observational constraint on the tensor-to-scalar ratio and the spectral index, we obtain $1.977<n<2.003$. We then investigate local-gravity tests for these unified models. The inflationary term becomes important at extremely high curvature in the action. However, we point out that it can be important at much lower curvature for the scalaron's potential and then its mass. Investigating how it works in the chameleon screening mechanism, we nonetheless find that the inflationary term does not relax or tighten the constraints on the three unified models in relevant density scales.

[31]  arXiv:2004.00874 [pdf, other]

Title: Influence of migration models and thermal torque on planetary growth in the pebble accretion scenario

Authors: Thomas Baumann, Bertram Bitsch

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

Low-mass planets that are in the process of growing larger within protoplanetary disks exchange torques with the disk and change their semi-major axis accordingly. This process is called type I migration and is strongly dependent on the underlying disk structure. As a result, there are many uncertainties about planetary migration in general. In a number of simulations, the current type I migration rates lead to planets reaching the inner edge of the disk within the disk lifetime. A new kind of torque exchange between planet and disk, the thermal torque, aims to slow down inward migration via the heating torque. The heating torque may even cause planets to migrate outwards, if the planetary luminosity is large enough. Here, we study the influence on planetary migration of the thermal torque on top of previous type I models. We find that the formula of Paardekooper et al. (2011) allows for more outward migration than that of Jim\'enez & Masset (2017) in most configurations, but we also find that planets evolve to very similar mass and final orbital radius using both formulae in a single planet-formation scenario, including pebble and gas accretion. Adding the thermal torque can introduce new, but small, regions of outwards migration if the accretion rates onto the planet correspond to typical solid accretion rates following the pebble accretion scenario. If the accretion rates onto the planets become very large, as could be the case in environments with large pebble fluxes (e.g., high-metallicity environments), the thermal torque can allow more efficient outward migration. However, even then, the changes for the final mass and orbital positions in our planet formation scenario are quite small. This implies that for single planet evolution scenarios, the influence of the heating torque is probably negligible.

[32]  arXiv:2004.00890 [pdf, other]

Title: S-stars motion around relativistic compact object Sgr A*

Authors: R. I. Gainutdinov, Yu. V. Baryshev, V. V. Sokolov

Comments: report at the Diversity of the Local Universe 2019 conference

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

A review of modern VLTI observations of the orbital motion of closest stars to the relativistic compact object Sgr A* and its ability to test gravitation theories in the conditions of Post-Newtonian approximation. The observed orbital parameters, second order Doppler effect and gravitational redshift, measured for several S-stars, are compared with theoretical PN predictions.

[33]  arXiv:2004.00902 [pdf, other]

Title: The Gravitational Wave Emission of Double White Dwarf Coalescences

Authors: Ze-Cheng Zou, Xiao-Long Zhou, Yong-Feng Huang

Comments: 8 pages, 5 figures, submitted to RAA

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

Type Ia Supernovae (SNe Ia) are widely used as standard candles to probe the Universe. However, how these fierce explosions are produced itself is still a highly debated issue. There are mainly two popular models for SNe Ia, i.e. the double-degenerate scenario and the single-degenerate scenario. The double-degenerate scenario suggests that SNe Ia are produced by the coalescence of two degenerate white dwarfs, while the single-degenerate scenario suggests that the continuous accretion of a single degenerate white dwarf from its normal stellar companion will finally lead to a disastrous explosion when it is over-massive, resulting in an SN Ia. The rapid development of the gravitational wave astronomy sheds new light on the nature of SNe Ia. In this study, we calculate the gravitational wave emissions of double white dwarf coalescences and compare them with the sensitivities of several upcoming detectors. It is found that the gravitational wave emissions from double white dwarf mergers in the locale universe are strong enough to be detected by LISA. We argue that LISA-like gravitational wave detectors sensitive in the frequency range of 0.01 - 0.1 Hz will be a powerful tool to test the double-degenerate model of SNe Ia, and also to probe the Universe.

[34]  arXiv:2004.00916 [pdf, other]

Title: The nature of the methanol maser ring G23.657$-$00.127. II. Expansion of the maser structure

Authors: Anna Bartkiewicz (1), Alberto Sanna (2 and 3), Marian Szymczak (1), Luca Moscadelli (4), Huib Jan van Langevelde (5 and 6), Pawel Wolak (1) ((1) Institute of Astronomy, Nicolaus Copernicus University, Torun, Poland, (2) INAF, Istituto di Radioastronomia & Italian ALMA Regional Centre, Bologna, Italy, (3) Max-Planck-Institut für Radioastronomie, Bonn, Germany, (4) INAF, Osservatorio Astrofisico di Arcetri, Firenze, Italy, (5) Joint Institute for VLBI ERIC (JIVE), Dwingeloo, The Netherlands, (6) Sterrewacht Leiden, Leiden University, Leiden, The Netherlands)

Comments: accepted for publication in A\&A, 15 pages including on-line material

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

Ring-like distributions of the 6.7 GHz methanol maser spots at milliarcsecond scales represent a family of molecular structures of unknown origin associated with high-mass young stellar objects (HMYSOs). We aim to study G23.657-00.127, which has a nearly circular ring of the 6.7 GHz methanol masers, and is the most suitable target to test hypotheses on the origin of the maser rings. The European Very Long Baseline Interferometry Network (EVN) was used at three epochs spanning 10.3 yr to derive the spatio-kinematical structure of the 6.7 GHz methanol maser emission in the target. The maser cloudlets, lying in a nearly symmetric ring, expand mainly in the radial direction with a mean velocity of 3.2 km s$^{-1}$. There is an indication that the radial component of the velocity increases with cloudlet's distance from the ring centre. The tangential component does not show any clear evidence for rotation of the cloudlets or any relationship with distance from the ring centre. The blue-shifted masers may hint at an anticlockwise rotation of cloudlets in the southern part of the ring. The nearly circular structure of the ring clearly persisted for more than 10 yr. Interferometric data demonstrated that about one quarter of cloudlets show significant variability in their brightness, although the overall spectrum was non-variable in single-dish studies. Taking into account the three-dimensional motion of the maser cloudlets and their spatial distribution along a small ring, we speculate about two possible scenarios where the methanol masers trace either a spherical outflow arising from an (almost) edge-on disc, or a wide angle wind at the base of a protostellar jet. The latter is associated with near- and mid-infrared emission detected towards the ring. High angular resolution images of complementary (thermal) tracers are needed to interpret the environment of methanol masers.

[35]  arXiv:2004.00934 [pdf, other]

Title: High-redshift star formation in the ALMA era

Authors: Jacqueline A. Hodge, Elisabete da Cunha

Comments: Invited Review for Royal Society Open Science, 60 pages + references

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

The Atacama Large Millimetre/submillimetre Array (ALMA) is currently in the process of transforming our view of star-forming galaxies in the distant ($z\gtrsim1$) universe. Before ALMA, most of what we knew about dust-obscured star formation in distant galaxies was limited to the brightest submillimetre sources -- the so-called submillimetre galaxies (SMGs) -- and even the information on those sources was sparse, with resolved (i.e., sub-galactic) observations of the obscured star formation and gas reservoirs typically restricted to the most extreme and/or strongly lensed sources. Starting with the beginning of early science operations in 2011, the last nine years of ALMA observations have ushered in a new era for studies of high-redshift star formation. With its long baselines, ALMA has allowed observations of distant dust-obscured star formation with angular resolutions comparable to -- or even far surpassing -- the best current optical telescopes. With its bandwidth and frequency coverage, it has provided an unprecedented look at the associated molecular and atomic gas in these distant galaxies through targeted follow-up and serendipitous detections/blind line scans. Finally, with its leap in sensitivity compared to previous (sub-)millimetre arrays, it has enabled the detection of these powerful dust/gas tracers much further down the luminosity function through both statistical studies of color/mass-selected galaxy populations and dedicated deep fields. We review the main advances ALMA has helped bring about in our understanding of the dust and gas properties of high-redshift ($z\gtrsim1$) star-forming galaxies during these first nine years of its science operations, and we highlight the interesting questions that may be answered by ALMA in the years to come.

[36]  arXiv:2004.00947 [pdf, other]

Title: Model-independent constraints in inflationary magnetogenesis

Authors: Yuri Shtanov, Mykhailo Pavliuk

Comments: 16 pages, 2 figures, corrected errors made in arXiv:1902.05894 and arXiv:1911.10424

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

We derive a simple model-independent upper bound on the strength of magnetic fields obtained in inflationary and post-inflationary magnetogenesis taking into account back-reaction and Schwinger effect. This bound turns out to be rather low for cosmologically interesting spatial scales. Somewhat higher upper bound is obtained if one assumes that some unknown mechanism suppresses the Schwinger effect in the early universe. Incidentally, we correct our previous estimates for this case.

[37]  arXiv:2004.00997 [pdf, ps, other]

Title: Crucial role of neutron diffusion in the crust of accreting neutron stars

Authors: Andrey Chugunov, Nikolay Shchechilin

Comments: Accepted for publication in MNRAS:Letters, 6 pages, 1 figure

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

Observed temperatures of transiently accreting neutron stars in the quiescent state are generally believed to be supported by deep crustal heating, associated with non-equilibrium exothermic reactions in the crust. Traditionally, these reactions are studied by considering nuclear evolution governed by compression of the accreted matter. Here we show that this approach has a basic weakness, that is that in some regions of the inner crust the conservative forces, applied for matter components (nuclei and neutrons), are not in mechanical equilibrium. In principle the force balance can be restored by dissipative forces, however the required diffusion fluxes are of the same order as total baryon flux at Eddington accretion. We argue that redistribution of neutrons in the inner crust should be involved in realistic model of accreted crust.

[38]  arXiv:2004.01017 [pdf]

Title: Initial results from the New Horizons exploration of 2014 MU69, a small Kuiper Belt Object

Authors: S. A. Stern, H. A. Weaver, J. R. Spencer, C. B. Olkin, G. R. Gladstone, W. M. Grundy, J. M. Moore, D. P. Cruikshank, H. A. Elliott, W. B. McKinnon, J. Wm. Parker, A. J. Verbiscer, L. A. Young, D. A. Aguilar, J. M. Albers, T. Andert, J. P. Andrews, F. Bagenal, M. E. Banks, B. A. Bauer, J. A. Bauman, K. E. Bechtold, C. B. Beddingfield, N. Behrooz, K. B. Beisser, S. D. Benecchi, E. Bernardoni, R. A. Beyer, S. Bhaskaran, C. J. Bierson, R. P. Binzel, E. M. Birath, M. K. Bird, D. R. Boone, A. F. Bowman, V. J. Bray, D. T. Britt, L. E. Brown, M. R. Buckley, M. W. Buie, B. J. Buratti, L. M. Burke, S. S. Bushman, B. Carcich, A. L. Chaikin, C. L. Chavez, A. F. Cheng, E. J. Colwell, S. J. Conard, M. P. Conner, C. A. Conrad, J. C. Cook, S. B. Cooper, O. S. Custodio, C. M. Dalle Ore, C. C. Deboy, P. Dharmavaram, et al. (148 additional authors not shown)

Comments: 43 pages, 8 figure

Journal-ref: Science 364, eaaw9771 (2019)

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

The Kuiper Belt is a distant region of the Solar System. On 1 January 2019, the New Horizons spacecraft flew close to (486958) 2014 MU69, a Cold Classical Kuiper Belt Object, a class of objects that have never been heated by the Sun and are therefore well preserved since their formation. Here we describe initial results from these encounter observations. MU69 is a bi-lobed contact binary with a flattened shape, discrete geological units, and noticeable albedo heterogeneity. However, there is little surface color and compositional heterogeneity. No evidence for satellites, ring or dust structures, gas coma, or solar wind interactions was detected. By origin MU69 appears consistent with pebble cloud collapse followed by a low velocity merger of its two lobes.

[39]  arXiv:2004.01039 [pdf, ps, other]

Title: A Pilot Study of Catching High-$z$ GRBs and Exploring Circumburst Environment in the Forthcoming SVOM Era

Authors: J. Wang, Y. L. Qiu, J. Y. Wei

Comments: 8 pages, 1 table and 3 figures, to be published in RAA

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

Rapid spectroscopy of GRB afterglows is an important and hard task. Based on the archival XS-GRB spectral database, we here perform a pilot study on the afterglow's spectroscopy in the forthcoming \it SVOM \rm era in two aspects. At first, our simulation indicates that the color acquired from the \it SVOM\rm/VT blue and red channels is effective in discriminating between low-$z$ ($z\lesssim3$) and distant GRB candidates until $z\sim6$. Secondly, by doubling the sample size, we find that the previously proposed global photoionization response of the circumburst gas to the prompt emission (i.e., the CIV/CII-$L_{\mathrm{iso}}/E^2_{\mathrm{peak}}$ relationship) is roughly confirmed, although the confirmation is dissatisfactory at the large $L_{\mathrm{iso}}/E^2_{\mathrm{peak}}$ end. We believe that this issue can be further addressed in the \it SVOM \rm era by larger spectroscopy sample, thanks to its capability of rapid identification of optical candidates of afterglow and its anti-solar pointing strategy.

[40]  arXiv:2004.01063 [pdf, ps, other]

Title: Radial migration of gap-opening planets in protoplanetary disks. II. The case of a planet pair

Authors: Kazuhiro D. Kanagawa, Ewa Szuszkiewicz

Comments: 23 pages, 21 figures, 2 tables, accepted for publication in The Astrophysical Journal

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

When two planets are born in a protoplanetary disk, they may enter into a mean-motion resonance as a consequence of the convergent planetary migration. The formation of mean-motion resonances is important for understanding how the planetary systems are shaped in the disk environments. Motivated by recent progress in the comprehension of the migration of partial gap-opening planets, we have investigated the orbital evolution of the planet pairs in a wide range of masses and disk properties with the aim to find out when the resonance capture is likely to happen. Using the formula for the migration timescale of the gap-opening planet developed in our previous work, we have derived a simple criterion which allows us to predict when the migration will be convergent (divergent). Further, we have verified the criterion using two-dimensional hydrodynamic simulations. We have found that the resonant pair of planets formed at the early phase of the evolution, can depart from the resonance at later times because the migration speed of the outer planet slows down due to the gap formation. Moreover, adopting our formula of the migration timescale, we have also carried out three-body simulations, which confirm the results of hydrodynamic simulations. Finally, we have compared our predictions with the observations, selecting a sample of known two-planet systems.

[41]  arXiv:2004.01069 [pdf, other]

Title: A Global Fireball Observatory

Authors: H. A. R. Devillepoix, M. Cupák, P. A. Bland, E. K. Sansom, M. C. Towner, R. M. Howie, B. A. D. Hartig, T. Jansen-Sturgeon, P. M. Shober, S. L. Anderson, G. K. Benedix, D. Busan, R. Sayers, P. Jenniskens, J. Albers, C. D. K. Herd, P. Carlson, P. J. A. Hill, P. G. Brown, Z. Krzeminski, G. R. Osinski, H. Chennaoui Aoudjehane, T. Shisseh, Z. Benkhaldoun, A. Jabiri, M. Guennoun, A. Barka, H. Darhmaoui, L. Daly, G. S. Collins, S. McMullan, M. D. Suttle, C. Shaw, J. S. Young, M. Alexander, A. D. Mardon, T. Ireland, G. Bonning, L. Baeza, T. Y. Alrefay, J. Horner, T. D. Swindle, C. W. Hergenrother, M. D. Fries, A. Tomkins, A. Langendam, T. A. Rushmer, C. O'Neill, D. Janches, J. L. Hormaechea

Comments: Submitted to PSS. 15 pages, 8 figures

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

The meteorite collections contain a very rich picture of what the early Solar System would have been made of, however the lack of spatial context with respect to their parent population for these samples is an issue. The asteroid population is equally as rich in surface mineralogies, and mapping these two populations (meteorites and asteroids) together is a major challenge for Planetary Science. Directly probing asteroids achieves this at a high cost. Observing meteorite falls and calculating their pre-atmospheric orbit on the other hand, is a cheaper way to approach the problem. The Global Fireball Observatory (GFO) collaboration was established in 2017 and brings together multiple institutions (from Australia, USA, Canada, Morocco, Saudi Arabia, the UK, and Argentina) to maximise the area for fireball observation time and therefore meteorite recoveries. The members have a choice to operate independently, but they can also choose to work in a fully collaborative manner with other GFO partners. This efficient approach leverages the experience gained from the Desert Fireball Network (DFN) pathfinder project in Australia. The state-of-the art technology (DFN camera systems and data reduction) and experience of the support teams is shared between all partners, freeing up time for science investigations and meteorite searching. With all networks combined together, the GFO collaboration already covers 0.6\% of the Earth's surface for meteorite recovery as of mid-2019, and aims to reach 2\% in the early 2020s. After 5 years of operation, the GFO will have observed a fireball from virtually every meteorite type. This combined effort will bring new, fresh, extra-terrestrial material to the labs, yielding new insights about the formation of the Solar System.

[42]  arXiv:2004.01104 [pdf, ps, other]

Title: Properties of green valley galaxies in relation to their selection criteria

Authors: Beatrice Nyiransengiyumva, Mirjana Povic, Pheneas Nkundabakura, Antoine Mahoro

Comments: Proceedings paper of the IAU symposium "Nuclear Activity in Galaxies Across Cosmic Time" (Ethiopia) accepted to be published under the Cambridge University Press, eds. M. Povic, P. Marziani, J. Masegosa, H. Netzer, S. H. Negu, and S. B. Tessema

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

The distribution of galaxies has been studied to show the difference between the blue cloud and red sequence and to define the green valley region. However, there are still many open questions regarding the importance of the green valley for understanding the morphological transformation and evolution of galaxies, how galaxies change from late-type to early-type and the role of AGN in galaxy formation and evolution scenario. The work focused on studying in more details the properties of green valley galaxies by testing the six most used selection criteria, differences between them, and how they may affect the main results and conclusions. The main findings are that, by selecting the green valley galaxies using different criteria, we are selecting different types of galaxies in terms of their stellar masses, sSFR, SFR, spectroscopic classification and morphological properties, where the difference was more significant for colour criteria than for sSFR and SFR vs. stellar-mass criteria.

[43]  arXiv:2004.01109 [pdf, ps, other]

Title: Tidal friction in satellites and planets. The new version of the creep tide theory

Authors: Sylvio Ferraz-Mello, Cristian Beaugé, Hugo Alberto Folonier, Gabriel Oliveira Gomes

Comments: 27 pages, 8 figures

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

Paper on the creep tide theory and its applications to satellites and planets with emphasis on a new set of differential equations allowing easier numerical studies. The creep tide theory is a new paradigm that does not fix a priori the tidal deformation of the body, but considers the deformation as a low-Reynolds-number flow. The evolution under tidal forces is ruled by an approximate solution of the Navier-Stokes equation depending on the body's viscosity with no ad hoc assumptions on its shape and orientation. It reproduces closely the results of Darwinian theories in the case of gaseous planets and stars, but the results are completely different in the case of stiff satellites and planets. It explains the tidal dissipations of Enceladus and Mimas. The extension of the theory to nonhomogeneous icy satellites with a subsurface ocean allows the amplitude of the forced oscillations around synchronization (librations) to be better determined.

[44]  arXiv:2004.01135 [pdf, other]

Title: Foreground cleaning and template-free stochastic background extraction for LISA

Authors: Mauro Pieroni, Enrico Barausse

Comments: 18 pages, 4 figures, 2 appendixes

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

Based on the rate of resolved stellar origin black hole and neutron star mergers measured by LIGO and Virgo, it is expected that these detectors will also observe an unresolved Stochastic Gravitational Wave Background (SGWB) by the time they reach design sensitivity. Since the same binaries observed by LIGO and Virgo pass through the LISA mHz frequency band at an earlier stage of their orbital evolution,it is foreseen that their SGWB will also be observable by LISA with Signal to Noise Ratio (SNR) $\sim 350$. Unlike the stochastic signal from Galactic white dwarf binaries, for which a subtraction is expected to be possible by exploiting its yearly modulation (induced by the motion of the LISA constellation), the background from unresolved stellar origin black hole and neutron star binaries acts as a foreground for other stochastic signals of cosmological or astrophysical origin, which may also be present in the LISA band. Here, we employ a principal component analysis to model and extract an additional hypothetical SGWB in the LISA band, without making any a priori assumptions on its spectral shape. At the same time, we account for the presence of the foreground from stellar origin black holes and neutron stars, as well as for possible uncertainties in the LISA noise calibration. We find that our technique leads to a linear problem and is therefore suitable for fast and reliable extraction of SGWBs with SNR up to ten times weaker than the LIGO/Virgo foreground, quite independently of their spectral shape.

[45]  arXiv:2004.01139 [pdf, other]

Title: The Atacama Cosmology Telescope: A CMB lensing mass map over 2100 square degrees of sky and its cross-correlation with BOSS-CMASS galaxies

Authors: Omar Darwish, Mathew S. Madhavacheril, Blake D. Sherwin, Simone Aiola, Nicholas Battaglia, James A. Beall, Daniel T. Becker, J. Richard Bond, Erminia Calabrese, Steve Choi, Mark J. Devlin, Jo Dunkley, Rolando Dünner, Anna E. Fox, Patricio A. Gallardo, Yilun Guan, Mark Halpern, Dongwon Han, Matthew Hasselfield, J. Colin Hill, Gene C. Hilton, Matt Hilton, Adam D. Hincks, Shuay-Pwu Patty Ho, J. Hubmayr, John P. Hughes, Brian J. Koopman, Arthur Kosowsky, J. Van Lanen, Thibaut Louis, Marius Lungu, Amanda MacInnis, Loïc Maurin, Jeffrey McMahon, Kavilan Moodley, Sigurd Naess, Toshiya Namikawa, Laura Newburgh, John P. Nibarger, Micheal D. Niemack, Bruce Partridge, Frank J. Qu, Naomi Robertson, Benjamin Schmitt, Neelima Sehgal, Cristóbal Sifón, David N. Spergel, Suzanne Staggs, et al. (3 additional authors not shown)

Comments: 16 pages, 11 figures, lensing map products will be made available on LAMBDA as part of the upcoming ACT data release

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

We construct cosmic microwave background lensing mass maps using data from the 2014 and 2015 seasons of observations with the Atacama Cosmology Telescope (ACT). These maps cover 2100 square degrees of sky and overlap with a wide variety of optical surveys. The maps are signal dominated on large scales and have fidelity such that their correlation with the cosmic infrared background is clearly visible by eye. We also create lensing maps with thermal Sunyaev-Zel'dovich contamination removed using a novel cleaning procedure that only slightly degrades the lensing signal-to-noise ratio. The cross-spectrum between the cleaned lensing map and the BOSS CMASS galaxy sample is detected at $10$-$\sigma$ significance, with an amplitude of $A=1.02 \pm 0.10$ relative to the Planck best-fit LCDM cosmological model with fiducial linear galaxy bias. Our measurement lays the foundation for lensing cross-correlation science with current ACT data and beyond.

[46]  arXiv:2004.01151 [pdf, other]

Title: Formation of NH2CHO and CH3CHO upon UV photoprocessing of interstellar ice analogs

Authors: Rafael Martin-Domenech, Karin I. Oberg, Mahesh Rajappan

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

Complex organic molecules (COMs) can be produced by energetic processing of interstellar ice mantles accreted on top of dust grains. Two COMs with proposed energetic ice formation pathways are formamide and acetaldehyde. Both have been detected in Solar System comets, and in different circumstellar and interstellar environments. In this work, we study the NH2CHO and CH3CHO formation upon UV photoprocessing of CO:NH3 and CO:CH4 ice samples. The conversion from NH2 radicals to NH2CHO is 2-16 times higher than the conversion from CH3 radicals to CH3CHO under the explored experimental conditions, likely because the formation of the latter competes with the formation of larger hydrocarbons. In addition, the conversion of NH2 into NH2CHO at 10 K increases with the NH3 abundance in the ice, and also with the temperature in CO-dominated CO:NH3 ices. This is consistent with the presence of a small NH2 and HCO reorientation barrier for the formation of NH2CHO, which is overcome with an increase in the ice temperature. The measured NH2CHO and CH3CHO formation efficiencies and rates are similar to those found during electron irradiation of the same ice samples under comparable conditions, suggesting that both UV photons and cosmic rays would have similar contributions to the solid-state formation of these species in space. Finally, the measured conversion yields (up to one order of magnitude higher for NH2CHO) suggest that in circumstellar environments, where the observed NH2CHO/CH3CHO abundance ratio is 0.1, there are likely additional ice and/or gas phase formation pathways for CH3CHO.

[47]  arXiv:2004.01161 [pdf, other]

Title: SYMBA: An end-to-end VLBI synthetic data generation pipeline

Authors: F. Roelofs, M. Janssen, I. Natarajan, R. Deane, J. Davelaar, H. Olivares, O. Porth, S. N. Paine, K. L. Bouman, R. P. J. Tilanus, I. M. van Bemmel, H. Falcke, K. Akiyama, A. Alberdi, W. Alef, K. Asada, R. Azulay, A. Baczko, D. Ball, M. Baloković, J. Barrett, D. Bintley, L. Blackburn, W. Boland, G. C. Bower, M. Bremer, C. D. Brinkerink, R. Brissenden, S. Britzen, A. E. Broderick, D. Broguiere, T. Bronzwaer, D. Byun, J. E. Carlstrom, A. Chael, C. Chan, S. Chatterjee, K. Chatterjee, M. Chen, Y. Chen, I. Cho, P. Christian, J. E. Conway, J. M. Cordes, G. B. Crew, Y. Cui, M. De Laurentis, J. Dempsey, G. Desvignes, J. Dexter, S. S. Doeleman, R. P. Eatough, V. L. Fish, E. Fomalont, R. Fraga-Encinas, P. Friberg, C. M. Fromm, J. L. Gómez, P. Galison, C. F. Gammie, R. García, O. Gentaz, et al. (146 additional authors not shown)

Comments: 20 pages, 15 figures, accepted for publication in A&A

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

Realistic synthetic observations of theoretical source models are essential for our understanding of real observational data. In using synthetic data, one can verify the extent to which source parameters can be recovered and evaluate how various data corruption effects can be calibrated. These studies are important when proposing observations of new sources, in the characterization of the capabilities of new or upgraded instruments, and when verifying model-based theoretical predictions in a comparison with observational data. We present the SYnthetic Measurement creator for long Baseline Arrays (SYMBA), a novel synthetic data generation pipeline for Very Long Baseline Interferometry (VLBI) observations. SYMBA takes into account several realistic atmospheric, instrumental, and calibration effects. We used SYMBA to create synthetic observations for the Event Horizon Telescope (EHT), a mm VLBI array, which has recently captured the first image of a black hole shadow. After testing SYMBA with simple source and corruption models, we study the importance of including all corruption and calibration effects. Based on two example general relativistic magnetohydrodynamics (GRMHD) model images of M87, we performed case studies to assess the attainable image quality with the current and future EHT array for different weather conditions. The results show that the effects of atmospheric and instrumental corruptions on the measured visibilities are significant. Despite these effects, we demonstrate how the overall structure of the input models can be recovered robustly after performing calibration steps. With the planned addition of new stations to the EHT array, images could be reconstructed with higher angular resolution and dynamic range. In our case study, these improvements allowed for a distinction between a thermal and a non-thermal GRMHD model based on salient features in reconstructed images.

Cross-lists for Fri, 3 Apr 20

[48]  arXiv:2004.00030 (cross-list from hep-th) [pdf, ps, other]

Title: The web of swampland conjectures and the TCC bound

Authors: David Andriot, Niccolò Cribiori, David Erkinger

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

Inspired by the recent Trans-Planckian Censorship conjecture (TCC), we propose a generalization of the swampland distance conjecture, which bounds the usual order one parameter $\lambda$ to be a half of the TCC value, i.e. $\lambda \geq \frac{1}{2}\sqrt{\frac{2}{3}}$ in 4d. In addition, we propose a correspondence between the swampland distance and de Sitter conjectures, relating the tower mass $m$ on the one side to the scalar potential $V$ on the other side schematically as $m\sim |V|^{\frac{1}{2}}$, in the large distance limit. These proposals suggest a generalization of the scalar weak gravity conjecture, and are supported by a variety of examples. The lower bound on $\lambda$ is verified explicitly in many cases in the literature. The TCC bound on the de Sitter conjecture parameter $c$ is checked as well on ten different no-go theorems, which are worked-out in detail, and $V$ is analysed in the asymptotic limit. In particular, new results on 4d scalar potentials from type II compactifications are obtained.

[49]  arXiv:2004.00039 (cross-list from gr-qc) [pdf, other]

Title: Scale symmetry, the Higgs and the Cosmos

Authors: Javier Rubio

Comments: 14 pages, 5 figures. Invited talk in Corfu Summer Institute 2019 "School and Workshops on Elementary Particle Physics and Gravity" (CORFU2019), based on 1712.04956 [astro-ph.CO] and 1811.05984 [astro-ph.CO]

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

I review the Higgs-Dilaton model: a scale-invariant extension of the Standard Model and gravity able to support inflation and dark energy with just an additional degree of freedom on top of the Standard Model content. Potential extensions of the simplest realization on the basis of transverse diffeomorphisms are also discussed.

[50]  arXiv:2004.00629 (cross-list from hep-ph) [pdf, other]

Title: Axion Kinetic Misalignment and Parametric Resonance from Inflation

Authors: Raymond T. Co, Lawrence J. Hall, Keisuke Harigaya, Keith A. Olive, Sarunas Verner

Comments: 40 pages, 6 figures

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

Axion cold dark matter from standard misalignment typically requires a decay constant $f_a~\gtrsim~10^{11}$ GeV. Kinetic misalignment and parametric resonance easily allow lower values of $f_a$ when the radial Peccei-Quinn (PQ) symmetry breaking field takes large initial values. Here, we consider the effects of inflation on kinetic misalignment and parametric resonance. We assume that the initial PQ field value is determined by quantum fluctuations, and is set by the Hubble parameter during inflation, $H_I$, and the PQ field mass. PQ field oscillations begin before or after the completion of reheating after inflation at a temperature $T_R$. We determine the range of $f_a$ and the inflationary parameters $(H_I, T_R)$ consistent with axion dark matter for a quartic potential for the PQ field. We find that $4\times 10^8$ GeV $< f_a < 10^{11}$ GeV can consistently produce axion dark matter. A significant portion of the allowed parameter space predicts rare kaon decays, $K_L \rightarrow (\pi^0 + \rm{missing \; energy})$, and/or suppression of structure formation on small scales.

[51]  arXiv:2004.00636 (cross-list from hep-ph) [pdf, other]

Title: Baryogenesis and Dark Matter from Freeze-In

Authors: Brian Shuve, David Tucker-Smith

Comments: 27 pages + appendices, 16 figures

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

We propose a simple model in which the baryon asymmetry and dark matter are created via the decays and inverse decays of QCD-triplet scalars, at least one of which must be in the TeV mass range. Singlet fermions produced in these decays constitute the dark matter. The singlets never reach equilibrium, and their coherent production, propagation, and annihilation generates a baryon asymmetry. We find that that the out-of-equilibrium condition and the dark matter density constraint typically require the lightest scalar to be long-lived, giving good prospects for detection or exclusion in current and upcoming colliders. In generalizing the leptogenesis mechanism of Akhmedov, Rubakov and Smirnov, our model expands the phenomenological possibilities for low-scale baryogenesis.

[52]  arXiv:2004.00643 (cross-list from hep-ph) [pdf, other]

Title: Phenomenology and Cosmology of No-Scale Attractor Models of Inflation

Authors: John Ellis, Dimitri V. Nanopoulos, Keith A. Olive, Sarunas Verner

Comments: 41 pages, 2 figures

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

We have recently proposed attractor models for modulus fixing, inflation, supersymmetry breaking and dark energy based on no-scale supergravity. In this paper we develop phenomenological and cosmological aspects of these no-scale attractor models that underpin their physical applications. We consider models in which inflation is driven by a modulus field ($T$-type) with supersymmetry broken by a Polonyi field, or a matter field ($\phi$-type) with supersymmetry broken by the modulus field. We derive the possible patterns of soft supersymmetry-breaking terms, which depend in $T$-type models whether the Polonyi and/or matter fields are twisted or not, and in $\phi$-type models on whether the inflaton and/or other matter fields are twisted or not. In $\phi$-type models, we are able to directly relate the scale of supersymmetry breaking to the inflaton mass. We also discuss cosmological constraints from entropy considerations and the density of dark matter on the mechanism for stabilizing the modulus field via higher-order terms in the no-scale K\"ahler potential.

[53]  arXiv:2004.00671 (cross-list from gr-qc) [pdf, other]

Title: Revisiting non-linearity in binary black hole mergers

Authors: Maria Okounkova

Comments: 8 pages, 5 figures

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

Recently, it has been shown that with the inclusion of overtones, the post-merger gravitational waveform at infinity of a binary black hole system is well-modelled using pure linear theory. However, given that a binary black hole merger is expected to be highly non-linear, where do these non-linearities, which do not make it out to infinity, go? We visualize quantities measuring non-linearity in the strong-field region of a numerical relativity binary black hole merger in order to begin to answer this question.

[54]  arXiv:2004.00736 (cross-list from physics.ins-det) [pdf, other]

Title: Characterization of sputtered hafnium thin films for high quality factor microwave kinetic inductance detectors

Authors: G. Coiffard, M. Daal, N. Zobrist, N. Swimmer, S. Steiger, B. Bumble, B. A. Mazin

Comments: 9 pages, 8 figures, 1 table. Submitted to SUST

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

Hafnium is an elemental superconductor which crystallizes in a hexagonal close packed structure, has a transition temperature $T_{C} \simeq 400 mK$, and has a high normal state resistivity around $90 \mu \Omega. cm$. In Microwave Kinetic Inductance Detectors (MKIDs), these properties are advantageous since they allow for creating detectors sensitive to optical and near infra-red radiation. In this work, we study how sputter conditions and especially the power applied to the target during the deposition, affect the hafnium $T_{C}$, resistivity, stress, texture and preferred crystal orientation. We find that the position of the target with respect to the substrate strongly affects the orientation of the crystallites in the films and the internal quality factor, $Q_{i}$, of MKIDs fabricated from the films. In particular, we demonstrate that a DC magnetron sputter deposition at a normal angle of incidence, low pressure, and low plasma power promotes the growth of compressive (002)-oriented films and that such films can be used to make high quality factor MKIDs with $Q_{i}$ up to 600,000.

[55]  arXiv:2004.00870 (cross-list from gr-qc) [pdf, other]

Title: GRMHD large eddy simulations with gradient subgrid-scale model

Authors: Daniele Viganò, Ricard Aguilera-Miret, Federico Carrasco, Borja Miñano, Carlos Palenzuela

Comments: 15 pages, 7 figures Submitted to PRD

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

The detection of binary neutron star mergers represents one of the most important astrophysical discoveries of the recent years. Due to the extreme matter and gravity conditions and the rich dynamics developed, it becomes a tremendous challenge to accurately simulate numerically all the scales present during the collision. Here we present how to study such systems by using large eddy simulations with a self-consistent subgrid-scale gradient model, that we generalized to the special relativistic case in a previous work and now extend to the general relativistic case. Adapted from nonrelativistic scenarios, the so-called gradient model allows to capture part of the effects of the hidden dynamics on the resolved scales, by means of a physically-agnostic, mathematically-based Taylor expansion of the nonlinear terms in the conservative evolution equations' fluxes. We assess the validity of this approach in bounding-box simulations of the magnetic Kelvin-Helmholtz instability. Several resolutions and a broad range of scenarios are considered in order to carefully test the performance of the model under three crucial aspects: (i) highly curved backgrounds, (ii) jumps on the fluid density profiles and (iii) strong shocks. The results suggest our extension of the gradient subgrid-scale model to general relativistic magnetohydrodynamics is a promising approach for studying binary neutron stars mergers, and potentially to other relevant astrophysical scenarios.

[56]  arXiv:2004.00888 (cross-list from gr-qc) [pdf, ps, other]

Title: Non-linear extension of non-metricity scalar for MOND

Authors: Fabio D'Ambrosio, Mudit Garg, Lavinia Heisenberg

Comments: 6 pages

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

General Relativity enjoys the freedom of different geometrical interpretations in terms of curvature, torsion or non-metricity. Within this geometrical trinity, a simpler geometrical formulation of General Relativity manifests itself in the latter, where gravity is entirely attributed to non-metricity. In this Letter, we consider non-linear extensions of Coincident General Relativity $f(\mathring{\mathbb{Q}})$ for phenomenological applications on both cosmological as well as galactic scales. The theory not only delivers dark energy on large scales but also recovers MOND on galactic scales, together with implications for the early universe cosmology. To the best of our knowledge, this represents the first relativistic, covariant, and ghost-free hybrid-formulation of MOND which recovers both, General Relativity and MOND in the appropriate limits and reconciles expected cosmological behavior. We further illustrate that previous bimetric formulations of MOND generically suffer from ghost instabilities and $f(\mathring{\mathbb{Q}})$ crystalizes as a unique ghost-free theory.

[57]  arXiv:2004.00985 (cross-list from physics.ins-det) [pdf]

Title: Cryogenic phonon-scintillation detectors with PMT readout for rare event search experiments

Authors: X. Zhang, J. Lin, V.B. Mikhailik, H. Kraus

Journal-ref: Astroparticle Physics, 79 (2016) 31-40

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

Cryogenic phonon-scintillation detectors (CPSD) for rare event search experiments require reliable, efficient and robust photon detectors that can resolve individual photons in a scintillation event.

[58]  arXiv:2004.01005 (cross-list from physics.chem-ph) [pdf, other]

Title: The high-temperature rotation-vibration spectrum and rotational clustering of silylene (SiH$_2$)

Authors: Victoria H. J. Clark, Alec Owens, Jonathan Tennyson, Sergei N. Yurchenko

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

A rotation-vibration line list for the electronic ground state ($\tilde{X}^{1}A_{1}$) of SiH$_2$ is presented. The line list, named CATS, is suitable for temperatures up to 2000 K and covers the wavenumber range 0 - 10,000 cm$^{-1}$(wavelengths $>1.0$ $\mu$m) for states with rotational excitation up to $J=52$. Over 310 million transitions between 593 804 energy levels have been computed variationally with a new empirically refined potential energy surface, determined by refining to 75 empirical term values with $J\leq 5$ and a newly computed high-level ab initio dipole moment surface. This is the first, comprehensive high-temperature line list to be reported for SiH$_2$ and it is expected to aid the study of silylene in plasma physics, industrial processes and possible astronomical detection. Furthermore, we investigate the phenomenon of rotational energy level clustering in the spectrum of SiH$_2$. The CATS line list is available from the ExoMol database (www.exomol.com) and the CDS database.

[59]  arXiv:2004.01021 (cross-list from hep-ph) [pdf, other]

Title: Fenomenología de modelos supersimétricos: partículas y materia oscura

Authors: Andres D. Perez

Comments: PhD thesis, 187 pages, in Spanish (Abstract in English). Based on arXiv:1608.08640, arXiv:1911.03191, and arXiv:1911.08550

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

To elucidate the composition of dark matter (DM) is one of the most important open questions in particle and astroparticle phenomenology. Within the framework of minimal supersymmetric extensions of the standard model of fundamental particles, the `mu-from-nu supersymmetric standard model', $\mu\nu$SSM, solves the $\mu$-problem and reproduces neutrino data, only adding couplings involving right-handed neutrinos. In this context, the supersymmetric partner of the graviton, known as gravitino, becomes a natural DM candidate. Working in the mentioned model, in this thesis we have analyzed the detection of gamma-ray signals arising from decaying gravitino DM considering experiments such as $\textit{Fermi}$-LAT. For this purpose all gravitino decays have been taken into account, complementing previous works. The possibility of an upcoming new generation of gamma-ray detectors has motivated the inclusion of axino, the supersymmetric partner of the axion, as a DM candidate. In this thesis, axino DM has been analyzed in the context of the $\mu\nu$SSM for the first time. Finally, scenarios with multicomponent DM have been studied, focusing on gravitinos and axinos coexisting as DM constituents. This novel scenario includes two very different cases with distinctive features: axino lighter than gravitino and vice versa. Considering the sensitivity of future MeV-GeV gamma-ray telescopes, axino and gravitino prospects of detection were analyzed in the mixed scenarios mentioned previously. In some parameter space regions, both candidates can produce a signal, therefore a double-line feature arises as a smoking gun that would uncover the DM composition.

[60]  arXiv:2004.01050 (cross-list from gr-qc) [pdf, other]

Title: Deep learning Gravitational Wave Detection in the Frequency Domain

Authors: Juan Pablo Marulanda, Camilo Santa, Antonio Enea Romano

Comments: 5 pages, 1 figures

Subjects: General Relativity and Quantum Cosmology (gr-qc); Instrumentation and Methods for Astrophysics (astro-ph.IM)

Detection of gravitational waves (GW) from compact binary mergers provide a new window into multimessenger astrophysics. The standard technique to determine the merger parameters is matched filtering, consisting in comparing the signal to a template bank. This approach can be time consuming and computationally expensive due to the large amount of experimental data which needs to be analyzed.
In the attempt to find more efficient data analysis methods we develop a new frequency domain convolutional neural network (FCNN) to predict the merger masses from the spectrogram of the detector signal, and compare it to previous time domain neural networks (TCNN). Since FCNNs are trained using spectrograms, the dimension of the input is reduced as compared to TCNNs, implying a substantially lower number of model parameters, consequently allowing faster processing, and a better out of sample performance. We find that in general FCNN have better performance on validation data and lower over-fit, providing a new promising approach to the analysis of GW detectors data.

[61]  arXiv:2004.01102 (cross-list from physics.space-ph) [pdf, other]

Title: Kinetic turbulence in space plasmas observed in the near-Earth and near-Sun solar wind

Authors: Olga Alexandrova, Vamsee Krishna Jagarlamudi, Claudia Rossi, Milan Maksimovic, Petr Hellinger, Yuri Shprits, André Mangeney

Comments: 12 pages, 7 figures, submitted to Nature Communications on March 2, 2020

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

Turbulence develops in any stressed flow when the scales of the forcing are much larger than those of the dissipation. In neutral fluids, it consists of chaotic motions in physical space but with a universal energy spectrum in Fourier space. Intermittency (non-Gaussian statistics of fluctuations) is another general property and it is related to the presence of coherent structures. Space plasmas are turbulent as well. Here, we focus on the kinetic plasma scales, which are not yet well understood. We address the following fundamental questions: (1) Do the turbulent fluctuations at kinetic scales form a universal spectrum? and (2) What is the nature of the fluctuations? Using measurements in the solar wind we show that the magnetic spectra of kinetic turbulence at 0.3, 0.6 and 0.9 AU from the Sun have the same shape as the ones close to the Earth orbit at 1 AU, indicating universality of the phenomenon. The fluctuations, which form this spectrum, are typically non-linearly interacting eddies that tend to generate magnetic filaments.

[62]  arXiv:2004.01152 (cross-list from physics.space-ph) [pdf, other]

Title: The Solar-wind with Hydrogen Ion Exchange and Large-scale Dynamics (SHIELD) model: A Self-Consistent Kinetic-MHD Model of the Outer Heliosphere

Authors: Adam T. Michael, Merav Opher, Gabor Toth, Valeriy Tenishev, Dmitry Borovikov

Comments: 21 pages, 6 figures. ApJS submitted

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

Neutral hydrogen has been shown to greatly impact the plasma flow in the heliopshere and the location of the heliospheric boundaries. We present the results of the Solar-wind with Hydrogen Ion Exchange and Large-scale Dynamics (SHIELD) model, a new, self-consistent, kinetic-MHD model of the outer heliosphere within the Space Weather Modeling Framework. The charge-exchange mean free path is on order of the size of the heliosphere; therefore, the neutral atoms cannot be described as a fluid. The SHIELD model couples the MHD solution for a single plasma fluid to the kinetic solution from for neutral hydrogen atoms streaming through the system. The kinetic code is based on the Adaptive Mesh Particle Simulator (AMPS), a Monte Carlo method for solving the Boltzmann equation. The SHIELD model accurately predicts the increased filtration of interstellar neutrals into the heliosphere. In order to verify the correct implementation within the model, we compare the results of the SHIELD model to other, well-established kinetic-MHD models. The SHIELD model matches the neutral hydrogen solution of these studies as well as the shift in all heliospheric boundaries closer to the Sun in comparison the the multi-fluid treatment of the neutral hydrogen atoms. Overall the SHIELD model shows excellent agreement to these models and is a significant improvement to the fluid treatment of interstellar hydrogen.

Replacements for Fri, 3 Apr 20

[63]  arXiv:1706.03811 (replaced) [pdf, other]

Title: STACCATO: A Novel Solution to Supernova Photometric Classification with Biased Training Sets

Authors: Esben A. Revsbech (1), Roberto Trotta (2), David A. van Dyk (1) ((1) Imperial Statistics (2) Imperial Astrophysics)

Comments: Matches version accepted by MNRAS, v3 only changes metadata to point to zenodo repository for the code. The STACCATO code is available from this https URL

Journal-ref: MNRAS, Volume 473, Issue 3, January 2018, 3969-3986

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

[64]  arXiv:1811.01966 (replaced) [pdf, ps, other]

Title: Line-driven disc wind in near-Eddington active galactic nuclei: decrease of mass accretion rate due to powerful outflow

Authors: Mariko Nomura, Ken Ohsuga, Chris Done

Comments: 12 pages, 7 figures, accepted for publication in MNRAS

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

[65]  arXiv:1905.11170 (replaced) [pdf, ps, other]

Title: Gravitational Wave Signatures of Highly Magnetized Neutron Stars

Authors: Cesar V. Flores, Luiz L. Lopes, Luis B. Castro, Débora P. Menezes

Comments: 20 pages, 4 figures, 6 tables

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

[66]  arXiv:1907.02963 (replaced) [pdf]

Title: Ice Giant Systems: The Scientific Potential of Missions to Uranus and Neptune (ESA Voyage 2050 White Paper)

Authors: Leigh N. Fletcher, Nicolas André, David Andrews, Michele Bannister, Emma Bunce, Thibault Cavalié, Sébastien Charnoz, Francesca Ferri, Jonathan Fortney, Davide Grassi, Léa Griton, Paul Hartogh, Ravit Helled, Ricardo Hueso, Geraint Jones, Yohai Kaspi, Laurent Lamy, Adam Masters, Henrik Melin, Julianne Moses, Olivier Mousis, Nadine Nettleman, Christina Plainaki, Elias Roussos, Jürgen Schmidt, Amy Simon, Gabriel Tobie, Paolo Tortora, Federico Tosi, Diego Turrini

Comments: 28 pages, 9 figures, version of Voyage2050 ESA white paper submitted to PSS

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

[67]  arXiv:1909.03236 (replaced) [src]

Title: Generation of strong magnetic fields in old neutron stars accounting for continuous chiral magnetic effect

Authors: Maxim Dvornikov (1), V.B. Semikoz (1), D.D. Sokoloff (2) ((1) IZMIRAN, (2) Moscow State University)

Comments: 14 pages in LaTeX2e, JCAP LaTeX style, 6 eps figures. The paper has been withdrawn since the main results are incorrect. We have partly corrected them in arXiv:2001.08139

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

[68]  arXiv:1909.13832 (replaced) [pdf, other]

Title: Internal delensing of Cosmic Microwave Background polarization B-modes with the POLARBEAR experiment

Authors: S. Adachi, M. A. O. Aguilar Faúndez, Y. Akiba, A. Ali, K. Arnold, C. Baccigalupi, D. Barron, D. Beck, F. Bianchini, J. Borrill, J. Carron, K. Cheung, Y. Chinone, K. Crowley, H. El Bouhargani, T. Elleflot, J. Errard, G. Fabbian, C. Feng, T. Fujino, N. Goeckner-Wald, M. Hasegawa, M. Hazumi, C. A. Hill, L. Howe, N. Katayama, B. Keating, S. Kikuchi, A. Kusaka, A. T. Lee, D. Leon, E. Linder, L. N. Lowry, F. Matsuda, T. Matsumura, Y. Minami, T. Namikawa, M. Navaroli, H. Nishino, J. Peloton, A. T. P. Pham, D. Poletti, G. Puglisi, C. L. Reichardt, Y. Segawa, B. D. Sherwin, M. Silva-Feaver, P. Siritanasak, R. Stompor, O. Tajima, S. Takatori, D. Tanabe, G. P. Teply, C. Vergès

Comments: Matches version published in Physical Review Letters

Journal-ref: Physical Review Letters, 124, 131301 (2020)

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

[69]  arXiv:1910.04168 (replaced) [pdf, other]

Title: A New Census of the 0.2 < z < 3.0 Universe, Part I: The Stellar Mass Function

Authors: Joel Leja, Joshua S. Speagle, Benjamin D. Johnson, Charlie Conroy, Pieter van Dokkum, Marijn Franx

Comments: 22 pages, 11 figures

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

[70]  arXiv:1910.04567 (replaced) [pdf, other]

Title: Binary Neutron Star Mergers with Missing Electromagnetic Counterparts as Manifestations of Mirror World

Authors: Revaz Beradze, Merab Gogberashvili, Alexander S. Sakharov

Comments: 11 pages, no figures, version accepted for publication in PLB

Journal-ref: Physics Letters B Volume 804, 10 May 2020, 135402

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

[71]  arXiv:1910.10473 (replaced) [pdf, other]

Title: A Surrogate Model for Gravitational Wave Signals from Comparable- to Large- Mass-Ratio Black Hole Binaries

Authors: Nur E. M. Rifat, Scott E. Field, Gaurav Khanna, Vijay Varma

Comments: 8 pages, 4 figures; includes improved modeling of the subdominant modes and a comparison to a high-mass ratio NR simulation; EMRI surrogate model is now publicly available at bhptoolkit.org

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

[72]  arXiv:1911.08512 (replaced) [pdf, other]

Title: Inflation models in the light of self-interacting sterile neutrinos

Authors: Arindam Mazumdar, Subhendra Mohanty, Priyank Parashari

Comments: 15 pages, 5 figures (matches accepted version to Phys.Rev.D)

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

[73]  arXiv:2001.00827 (replaced) [pdf, ps, other]

Title: Resolving the Nuclear Radio Emission from M32 with Very Large Array

Authors: Sijia Peng, Zhiyuan Li, Loránt O. Sjouwerman, Yang Yang, Fuguo Xie, Feng Yuan

Comments: 12 peges, 3 figures, accepted for publication in ApJ. Comments welcome

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

[74]  arXiv:2001.01737 (replaced) [pdf, other]

Title: A search for IceCube events in the direction of ANITA neutrino candidates

Authors: IceCube Collaboration: M. G. Aartsen, M. Ackermann, J. Adams, J. A. Aguilar, M. Ahlers, M. Ahrens, C. Alispach, K. Andeen, T. Anderson, I. Ansseau, G. Anton, C. Argüelles, J. Auffenberg, S. Axani, P. Backes, H. Bagherpour, X. Bai, A. Balagopal V., A. Barbano, S. W. Barwick, B. Bastian, V. Baum, S. Baur, R. Bay, J. J. Beatty, K.-H. Becker, J. Becker Tjus, S. BenZvi, D. Berley, E. Bernardini, D. Z. Besson, G. Binder, D. Bindig, E. Blaufuss, S. Blot, C. Bohm, S. Böser, O. Botner, J. Böttcher, E. Bourbeau, J. Bourbeau, F. Bradascio, J. Braun, S. Bron, J. Brostean-Kaiser, A. Burgman, J. Buscher, R. S. Busse, T. Carver, C. Chen, E. Cheung, D. Chirkin, S. Choi, K. Clark, L. Classen, A. Coleman, G. H. Collin, J. M. Conrad, P. Coppin, P. Correa, D. F. Cowen, R. Cross, P. Dave, C. De Clercq, et al. (296 additional authors not shown)

Journal-ref: The Astrophysical Journal, Volume 892, Number 1 (2020)

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

[75]  arXiv:2001.04865 (replaced) [pdf, other]

Title: Water production rates and activity of interstellar comet 2I/Borisov

Authors: Zexi Xing, Dennis Bodewits, John Noonan, Michele T. Bannister

Comments: 12 pages, 3 figures, 2 tables, submitted to ApJL

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

[76]  arXiv:2002.07854 (replaced) [pdf, ps, other]

Title: Detecting Pair-Instability Supernovae at z<5 with the James Webb Space Telescope

Authors: Eniko Regos, Jozsef Vinko, Bodo L. Ziegler

Comments: Accepted for ApJ, in press

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

[77]  arXiv:2003.00017 (replaced) [pdf, other]

Title: From parallel to perpendicular -- On the orientation of magnetic fields in molecular clouds

Authors: D. Seifried, S. Walch, M. Weis, S. Reissl, J. D. Soler, R. S. Klessen, P. R. Joshi

Comments: 17 pages, 11 figures, submitted to MNRAS, comments are welcome, corrected formatting mistake in equations

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

[78]  arXiv:2003.00477 (replaced) [pdf, other]

Title: Shadow and Quasinormal Modes of a Rotating Loop Quantum Black Hole

Authors: Cheng Liu, Tao Zhu, Qiang Wu, Kimet Jusufi, Mubasher Jamil, Mustapha Azreg-Aïnou, Anzhong Wang

Comments: 21 pages, 12 figures; v2: several references added and version published in Phys. Rev. D

Journal-ref: Phys. Rev. D 101, 084001 (2020)

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

[79]  arXiv:2003.05501 (replaced) [pdf, other]

Title: Holographic duality and mode stability of de Sitter space in semiclassical gravity

Authors: Paul M. Chesler, Abraham Loeb

Comments: 11 pages, one figure, clarifications added in v2

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

[80]  arXiv:2003.05784 (replaced) [pdf, other]

Title: Fractional Gravity and Modified Newtonian Dynamics

Authors: Gabriele U. Varieschi

Comments: 23 pages, including 4 figures: minor changes, revised last three paragraphs of Appendix B, and references added

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

[81]  arXiv:2003.10686 (replaced) [pdf, ps, other]

Title: Primordial tensor non-Gaussianities from general single-field inflation with non-Bunch-Davies initial states

Authors: Shingo Akama, Shin'ichi Hirano, Tsutomu Kobayashi

Comments: 9 pages

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

[82]  arXiv:2003.11121 (replaced) [pdf, other]

Title: Carnegie Supernova Project-II: A new method to photometrically identify sub-types of extreme Type Ia Supernovae

Authors: C. Ashall, J. Lu, C. Burns, E. Y. Hsiao, M. Stritzinger, N. B. Suntzeff, M. M. Phillips, E. Baron, C. Contreras, S. Davis, L. Galbany, P. Hoeflich, S. Holmbo, N. Morrell, E. Karamehmetoglu, K. Krisciunas, S. Kumar, M. Shahbandeh, S. Uddin

Comments: accepted for publication in ApjL, one additional 03fg-like SNe add compared to the previous version

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

• New submissions
• Cross-lists
• Replacements