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New submissions for Thu, 19 Mar 20

[1]  arXiv:2003.07856 [pdf, ps, other]

Title: Study of the Modified Gaussian Model on olivine diagnostic spectral features and its applications in space weathering experiments

Authors: Hui-Jie Han, Xiao-Ping Lu, Ya-Zhou Yang, Hao Zhang, Admire Muchimamui Mutelo

Comments: 27 pages, 15 figures

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

The absorption features of olivine in visible and near-infrared (VNIR) reflectance spectra are the key spectral parameters in its mineralogical studies. Generally, these spectral parameters can be obtained by exploiting the Modified Gaussian Model (MGM) with a proper continuum removal. However, different continua may change the deconvolution results of these parameters. This paper investigates the diagnostic spectral features of olivine with diverse chemical compositions. Four different continuum removal methods with MGM for getting the deconvolution results are presented and the regression equations for predicting the Mg-number (Fo#) are introduced. The results show that different continua superimposed on the mineral absorption features will make the absorption center shift, as well as the obvious alterations in shape, width, and strength of the absorption band. Additionally, it is also found that the logarithm of a second-order polynomial continuum can match the overall shape of the spectrum in logarithmic space, and the improved regression equations applied to estimate the chemical composition of olivine-dominated spectra also have a better performance. As an application example, the improved approach is applied to pulse laser irradiated olivine grains to simulate and study the space weathering effects on olivine diagnostic spectral features. The experiments confirm that space weathering can make the absorption band center shift toward longer wavelength. Therefore, the Fo# estimated from remote sensing spectra may be less than its actual chemical composition. These results may provide valuable information for revealing the difference between the spectra of olivine grains and olivine-dominated asteroids.

[2]  arXiv:2003.07863 [pdf, ps, other]

Title: Giant star-forming clumps?

Authors: R. J. Ivison (ESO), J. Richard, A. D. Biggs, M. A. Zwaan, E. Falgarone, V. Arumugam, P. P. van der Werf, W. Rujopakarn

Comments: 5 pages; 3 figures; in press as a Letter to MNRAS

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

With the spatial resolution of the Atacama Large Millimetre Array (ALMA), dusty galaxies in the distant Universe typically appear as single, compact blobs of dust emission, with a median half-light radius, $\approx$ 1 kpc. Occasionally, strong gravitational lensing by foreground galaxies or galaxy clusters has probed spatial scales 1-2 orders of magnitude smaller, often revealing late-stage mergers, sometimes with tantalising hints of sub-structure. One lensed galaxy in particular, the Cosmic Eyelash at $z=$ 2.3, has been cited extensively as an example of where the interstellar medium exhibits obvious, pronounced clumps, on a spatial scale of $\approx$ 100 pc. Seven orders of magnitude more luminous than giant molecular clouds in the local Universe, these features are presented as circumstantial evidence that the blue clumps observed in many $z\sim$ 2-3 galaxies are important sites of ongoing star formation, with significant masses of gas and stars. Here, we present data from ALMA which reveal that the dust continuum of the Cosmic Eyelash is in fact smooth and can be reproduced using two S\'ersic profiles with effective radii, 1.2 and 4.4 kpc, with no evidence of significant star-forming clumps down to a spatial scale of $\approx$ 80 pc and a star-formation rate of $<$ 3 M$_\odot$ yr$^{-1}$.

[3]  arXiv:2003.07865 [pdf, other]

Title: HII regions in the CALIFA survey: I. Catalog presentation

Authors: C. Espinosa-Ponce, S. F. Sánchez, C. Morisset, J. K. Barrera-Ballesteros, L. Galbany, R. García-Benito, E. A. D. Lacerda, D. Mast

Comments: 26 pages, 14 figures

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

We present a new catalog of HII regions based on the integral field spectroscopy (IFS) data of the extended CALIFA and PISCO samples. The selection of HII regions was based on two assumptions: a clumpy structure with high contrast of H$\alpha$ emission and an underlying stellar population comprising young stars. The catalog provides the spectroscopic information of 26,408 individual regions corresponding to 924 galaxies, including the flux intensities and equivalent widths of 51 emission lines covering the wavelength range between 3745-7200A. To our knowledge, this is the largest catalog of spectroscopic properties of HII regions. We explore a new approach to decontaminate the emission lines from diffuse ionized gas contribution. This diffuse gas correction was estimated to correct every emission line within the considered spectral range. With the catalog of HII regions corrected, new demarcation lines are proposed for the classical diagnostic diagrams. Finally, we study the properties of the underlying stellar populations of the HII regions. It was found that there is a direct relationship between the ionization conditions on the nebulae and the properties of stellar populations besides the physicals condition on the ionized regions.

[4]  arXiv:2003.07866 [pdf, other]

Title: Repeated Impact-Driven Plume Formation On Enceladus Over Myr Timescales

Authors: Amir Siraj, Abraham Loeb

Comments: 5 pages, 4 figures; submitted to ApJL

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

Water plumes erupting from the `tiger stripe' features on the south pole of Enceladus are thought to connect to a global subsurface ocean. Proposed origins for the initial stress necessary to form the `tiger stripes' include a giant impact, which would require true polar wander, or tensile stresses, which would require a partial freezing of the subsurface ocean. A further issue with these hypotheses is that the `tiger stripes' may be short-lived. We show here that impact resurfacing can seal off plumes and mass loss can lead to their compression and closure over $\sim 1 \mathrm{\;Myr}$. Since plumes are observed at present, a mechanism by which new plumes can be generated every $\sim 1 \mathrm{\;Myr}$ and by which such plumes are most likely to form at the south pole is needed. We propose and investigate the possibility that impacts constitute a adequate repeating source for the continual instigation of fractures and plumes. We find that the rate of impacts on Enceladus suggests the formation of $\sim 10^3$ independent plume systems per Gyr, the vast majority on the south pole, and is consistent with the Cassini-derived age of the south pole for a lunar-like bombardment history, our estimates of fracture lifetimes, and with the needed parameters for parallel fracture propagation. The model favors a bombardment history similar to that of Triton over one more similar to that of the Galilean satellites, and favors a cumulative power-law index of 4.2 for impactors with radius, $1 \mathrm{\;km} < R < 10 \mathrm{\;km}$.

[5]  arXiv:2003.07869 [pdf, other]

Title: All sky angular power spectrum: I. Estimating brightness temperature fluctuations using TGSS 150 MHz survey

Authors: Samir Choudhuri, Abhik Ghosh, Nirupam Roy, Somnath Bharadwaj, Huib. T. Intema, Sk. Saiyad Ali

Comments: 11 pages, 7 figures, Accepted for publication in MNRAS

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

Measurements of the Galactic synchrotron emission is relevant for the 21-cm studies from the Epoch of Reionization. The study of the synchrotron emission is also useful to quantify the fluctuations in the magnetic field and the cosmic ray electron density of the turbulent interstellar medium (ISM) of our Galaxy. Here, we present the all-sky angular power spectrum $(C_{\ell})$ measurements of the diffuse synchrotron emission using the TIFR GMRT Sky Survey (TGSS) at 150 {\rm MHz}. We estimate $C_{\ell}$ using visibility data both before and after subtracting the modelled point sources. The amplitude of the measured $C_{\ell}$ falls significantly after subtracting the point sources, and it is also slightly higher in the Galactic plane for the residual data. The residual $C_{\ell}$ is most likely to be dominated by the Galactic synchrotron emission. The amplitude of the residual $C_{\ell}$ falls significantly away from the Galactic plane. We find the measurements are quite symmetric in the Northern and Southern hemispheres except in the latitude range $15-30^{\circ}$ which is the transition region from the disk dominated to diffuse halo dominated region. The comparison between this interferometric measurement with the scaled version of the Haslam rms map at 150 {\rm MHz} shows that the correlation coefficient $(r)$ is more than 0.5 for most of the latitude ranges considered here. This signifies the TGSS survey is quite sensitive to the diffuse Galactic synchrotron radiation.

[6]  arXiv:2003.07871 [pdf, other]

Title: Globular Clusters in the Sagittarius stream. Revising members and candidates with Gaia DR2

Authors: M. Bellazzini, R. Ibata, K. Malhan, N. Martin, B. Famaey, G. Thomas

Comments: Accepted for publication by Astronomy & Astrophysics. Latex, 9 pages, 7 color figures

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

We reconsider the case for the association of Galactic globular clusters (GCs) to the tidal stream of the Sagittarius dwarf spheroidal galaxy (Sgr dSph), using Gaia DR2 data. We use RR Lyrae to trace the stream in 6D and we select clusters matching the observed stream in position and velocity. In addition to the clusters residing in the main body of the galaxy (M 54, Ter 8, Ter 7, Arp 2) we confirm the membership of Pal 12 and Whiting 1 to the portion of the trailing arm populated by stars lost during recent perigalactic passages. NGC 2419, NGC 5634 and NGC 4147 are very interesting candidates, possibly associated to more ancient wraps of the stream. We note that all these clusters, with the exception of M 54, that lies within the stellar nucleus of the galaxy, are found in the trailing arm of the stream. The selected clusters are fully consistent with the [Fe/H] vs. [Mg/Fe], [Ca/Fe] patterns and the age-metallicity relation displayed by field stars in the main body of Sgr dSph.

[7]  arXiv:2003.07887 [pdf, other]

Title: Multiwavelength Absolute Magnitudes and Colours of Red Clump Stars in {\it Gaia} Era

Authors: Olcay Plevne, Özgecan Önal Taş, Selçuk Bilir, George M. Seabroke

Comments: Accepted by APJ

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

This study presents the multi-wavelength investigation of the absolute magnitudes and colours of the red clump (RC) stars selected from APOGEE and GALAH DR2 combined catalogue which is complemented with {\it Gaia} DR2 astrometric data and multi-wavelength photometric data of {\it GALEX} GR6/7, SDSS DR7, {\it Gaia} DR2, 2MASS and {\it WISE} sky surveys. The analyses are centred on the different distance estimation methods using {\it Gaia} trigonometric parallaxes, (1/$\varpi$) and Bayes statistics, and chemically defined Galactic disc populations on [$\alpha$/Fe]$\times$[Fe/H] plane. Such investigation questions the long studied problem of the population effects on RC luminosity. Using two different distance estimation approach, (i) chemical thin and chemical thick disc RC stars are shown to have different absolute magnitudes, while colours remain the same in all photometric bands. Absolute magnitudes vary between -0.12 and +0.13 mag for the 1/$\varpi$ with the change of the Galactic population. This variation in absolute magnitudes is found to be larger for the other method. (ii) The Besan\c con population synthesis model of Galaxy for 2MASS photometry, in which the absolute magnitude difference between chemical populations were found between -0.35 and -0.40 mag from thin disc to thick disc. When results compared with each other, differences of absolute magnitudes are about three times larger in the model than observations. We confirm that the RC absolute magnitudes depend on $\alpha$-element abundances of Galactic populations.

[8]  arXiv:2003.07922 [pdf, ps, other]

Title: Accretion Properties of PDS 70b with MUSE

Authors: Jun Hashimoto, Yuhiko Aoyama, Mihoko Konishi, Taichi Uyama, Shinsuke Takasao, Masahiro Ikoma, Takayuki Tanigawa

Comments: Accepted for publication in The Astronomical Journal

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

We report a new evaluation of the accretion properties of PDS~70b obtained with VLT/MUSE. The main difference from previous studies in Haffert et al. (2019) and Aoyama & Ikoma (2019) is in the mass accretion rate. Simultaneous multiple line observations, such as H$\alpha$ and H$\beta$, can better constrain the physical properties of an accreting planet. While we clearly detected H$\alpha$ emissions from PDS~70b, no H$\beta$ emissions were detected. We estimate the line flux of H$\beta$ with a 3-$\sigma$ upper limit to be 2.3~$\times$~10$^{-16}$~erg~s$^{-1}$~cm$^{-2}$. The flux ratio $F_{\rm H\beta}$/$F_{\rm H\alpha}$ for PDS~70b is $<$~0.28. Numerical investigations by Aoyama et al. (2018) suggest that $F_{\rm H\beta}$/$F_{\rm H\alpha}$ should be close to unity if the extinction is negligible. We attribute the reduction of the flux ratio to the extinction, and estimate the extinction of H$\alpha$ ($A_{\rm H\alpha}$) for PDS~70b to be $>$~2.0~mag using the interstellar extinction value. %The expected $A_{\rm H\alpha}$ value in the gap of the protoplanetary disk at the PDS~70b location is 2.4~mag, which is consistent with the estimated extinction. By combining with the H$\alpha$ linewidth and the dereddening line luminosity of H$\alpha$, %we derive the PDS~70b dynamical mass and mass accretion rate to be \hashimotor{12~$\pm$~3~$M_{\rm Jup}$} and $\gtrsim$~5~$\times$~10$^{-7}$~$M_{\rm Jup}$~yr$^{-1}$, respectively. we derive the PDS~70b mass accretion rate to be $\gtrsim$~5~$\times$~10$^{-7}$~$M_{\rm Jup}$~yr$^{-1}$. The PDS~70b mass accretion rate is an order of magnitude larger than that of PDS~70. We found that the filling factor $f_{\rm f}$ (the fractional area of the planetary surface emitting H$\alpha$) is $\gtrsim$0.01, which is similar to the typical stellar value. The small value of $f_{\rm f}$ indicates that the H$\alpha$ emitting areas are localized at the surface of PDS~70b.

[9]  arXiv:2003.07944 [pdf, ps, other]

Title: Chandra Resolves the Double FU Orionis System RNO 1B/1C in X-rays

Authors: Stephen L. Skinner, Manuel Guedel

Comments: 6 pages, 4 figures

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

We present new Chandra X-ray observations of the close pair of young stars RNO 1B and 1C (6$''$ separation) located in the L1287 cloud. RNO 1B erupted in 1978 - 1990 and is classified as an FU Orionis star (FUor). RNO 1C also shows most of the properties of an FUor but no eruption has yet been seen. Only a few dozen FUors are known and the presence of two such objects with a small angular separation is rare, suggesting a common origin. Both stars were faintly detected by Chandra and we summarize their X-ray properties within the framework of other previously detected FUors. We also report other X-ray detections in L1287 including the deeply-embedded young star RNO 1G, the jet-like radio source VLA 3, and an enigmatic hard flaring source with no 2MASS counterpart that was only detected in the second of two Chandra exposures.

[10]  arXiv:2003.07956 [pdf, other]

Title: Limits on $w$CDM from the EFTofLSS with the PyBird code

Authors: Guido D'Amico, Leonardo Senatore, Pierre Zhang

Comments: 27 pages, 6 tables, 8 figures. The PyBird code is available at this https URL

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

We apply the Effective Field Theory of Large-Scale Structure to analyze the $w$CDM cosmological model. By using the full shape of the power spectrum and the BAO post-reconstruction measurements from BOSS, the Supernovae from Pantheon, and a prior from BBN, we set the competitive CMB-independent limit $w=-1.046_{-0.052}^{+0.055}$ at $68\%$ C.L.. After adding the Planck CMB data, we find $w=-1.023_{-0.030}^{+0.033}$ at $68\%$ C.L.. Our results are obtained using PyBird, a new, fast Python-based code which we make publicly available.

[11]  arXiv:2003.07983 [pdf, other]

Title: The rotation of alpha Oph investigated using polarimetry

Authors: Jeremy Bailey, Daniel V. Cotton, Ian D. Howarth, Fiona Lewis, Lucyna Kedziora-Chudczer

Comments: 14 pages, 11 figures, 5 tables, Accepted in MNRAS

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

Recently we have demonstrated that high-precision polarization observations can detect the polarization resulting from the rotational distortion of a rapidly rotating B-type star. Here we investigate the extension of this approach to an A-type star. Linear-polarization observations of $\alpha$ Oph (A5IV) have been obtained over wavelengths from 400 to 750 nm. They show the wavelength dependence expected for a rapidly-rotating star combined with a contribution from interstellar polarization. We model the observations by fitting rotating-star polarization models and adding additional constraints including a measured $v_e \sin{i}$. However, we cannot fully separate the effects of rotation rate and inclination, leaving a range of possible solutions. We determine a rotation rate $\omega = \Omega/\Omega_ c$ between 0.83 and 0.98 and an axial inclination i > 60 deg. The rotation-axis position angle is found to be 142 $\pm$ 4 deg, differing by 16 deg from a value obtained by interferometry. This might be due to precession of the rotation axis due to interaction with the binary companion. Other parameters resulting from the analysis include a polar temperature Tp = 8725 $\pm$ 175 K, polar gravity $\log{g_p} = 3.93 \pm 0.08$ (dex cgs), and polar radius $R_{\rm p} = 2.52 \pm 0.06$ Rsun. Comparison with rotating-star evolutionary models indicates that $\alpha$ Oph is in the later half of its main-sequence evolution and must have had an initial $\omega$ of 0.8 or greater. The interstellar polarization has a maximum value at a wavelength ($\lambda_{\rm max}$) of $440 \pm 110$ nm, consistent with values found for other nearby stars.

[12]  arXiv:2003.07985 [pdf, ps, other]

Title: Tether Capture of spacecraft at Neptune

Authors: J. R. Sanmartín, J. Peláez

Comments: 6 pages, 5 figures

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

Past planetary missions have been broad and detailed for Gas Giants, compared to flyby missions for Ice Giants. Presently, a mission to Neptune using electrodynamic tethers is under consideration due to the ability of tethers to provide free propulsion and power for orbital insertion as well as additional exploratory maneuvering --- providing more mission capability than a standard orbiter mission. Tether operation depends on plasma density and magnetic field $\mathbf{B}$, though tethers can deal with ill-defined density profiles, with the anodic segment self-adjusting to accommodate densities. Planetary magnetic fields are due to currents in some small volume inside the planet, magnetic-moment vector, and typically a dipole law approximation --- which describes the field outside. When compared with Saturn and Jupiter, the Neptunian magnetic structure is significantly more complex: the dipole is located below the equatorial plane, is highly offset from the planet center, and at large tilt with its rotation axis. Lorentz-drag work decreases quickly with distance, thus requiring spacecraft periapsis at capture close to the planet and allowing the large offset to make capture efficiency (spacecraft-to-tether mass ratio) well above a no-offset case. The S/C might optimally reach periapsis when crossing the meridian plane of the dipole, with the S/C facing it; this convenient synchronism is eased by Neptune rotating little during capture. Calculations yield maximum efficiency of approximately 12, whereas a $10^{\circ}$ meridian error would reduce efficiency by about 6%. Efficiency results suggest new calculations should be made to fully include Neptunian rotation and consider detailed dipole and quadrupole corrections.

[13]  arXiv:2003.07997 [pdf, other]

Title: On the saturation mechanism of the fluctuation dynamo at ${\text{Pr}_\mathrm{M}} \ge 1$

Authors: Amit Seta, Paul J. Bushby, Anvar Shukurov, Toby S. Wood

Comments: 17 pages, 19 figures, accepted for publication in Physical Review Fluids

Subjects: Astrophysics of Galaxies (astro-ph.GA); Fluid Dynamics (physics.flu-dyn); Plasma Physics (physics.plasm-ph)

The presence of magnetic fields in many astrophysical objects is due to dynamo action, whereby a part of the kinetic energy is converted into magnetic energy. A turbulent dynamo that produces magnetic field structures on the same scale as the turbulent flow is known as the fluctuation dynamo. We use numerical simulations to explore the nonlinear, statistically steady state of the fluctuation dynamo in driven turbulence. We demonstrate that as the magnetic field growth saturates, its amplification and diffusion are both affected by the back-reaction of the Lorentz force upon the flow. The amplification of the magnetic field is reduced due to stronger alignment between the velocity field, magnetic field, and electric current density. Furthermore, we confirm that the amplification decreases due to a weaker stretching of the magnetic field lines. The enhancement in diffusion relative to the field line stretching is quantified by a decrease in the computed local value of the magnetic Reynolds number. Using the Minkowski functionals, we quantify the shape of the magnetic structures produced by the dynamo as magnetic filaments and ribbons in both kinematic and saturated dynamos and derive the scalings of the typical length, width, and thickness of the magnetic structures with the magnetic Reynolds number. We show that all three of these magnetic length scales increase as the dynamo saturates. The magnetic intermittency, strong in the kinematic dynamo (where the magnetic field strength grows exponentially) persists in the statistically steady state, but intense magnetic filaments and ribbons are more volume-filling.

[14]  arXiv:2003.08014 [pdf, other]

Title: Numerical solutions to Einstein's equations in a shearing-dust Universe: a code comparison

Authors: Julian Adamek, Cristian Barrera-Hinojosa, Marco Bruni, Baojiu Li, Hayley J. Macpherson, James B. Mertens

Comments: 13 pages, 5 figures

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

A number of codes for general-relativistic simulations of cosmological structure formation have been developed in recent years. Here we demonstrate that a sample of these codes produce consistent results beyond the Newtonian regime. We simulate solutions to Einstein's equations dominated by gravitomagnetism --- a vector-type gravitational field that doesn't exist in Newtonian gravity and produces frame-dragging, the leading-order post-Newtonian effect. We calculate the coordinate-invariant effect on intersecting null geodesics by performing ray tracing in each independent code. With this observable quantity, we assess and compare each code's ability to compute relativistic effects.

[15]  arXiv:2003.08016 [pdf, other]

Title: Variations of the physical parameters of the blazar Mrk 421 based on the analysis of the spectral energy distributions

Authors: Yurika Yamada, Makoto Uemura, Ryosuke Itoh, Yasushi Fukazawa, Masanori Ohno, Fumiya Imazato

Comments: 20 pages, 16 figures, accepted for publication in PASJ

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

We report on the variations of the physical parameters of the jet observed in the blazar Mrk 421, and discuss the origin of X-ray flares in the jet, based on the analysis of the several spectral energy distributions (SEDs). The SEDs are modeled using the one-zone synchrotron self-Compton (SSC) model and its parameters determined using a Markov chain Monte Carlo method. The lack of data at TeV energies means many of the parameters cannot be uniquely determined and are correlated. These are studied in detail. We found that the optimal solution can be uniquely determined only when we apply a constraint to one of four parameters: the magnetic field (B), Doppler factor, size of the emitting region, and normalization factor of the electron energy distribution. We used 31 sets of SED from 2009 to 2014 with optical-UV data observed with UVOT/Swift and the Kanata telescope, X-ray data with XRT/Swift, and gamma-ray data with the Fermi Large Area Telescope (LAT). The result of our SED analysis suggests that, in the X-ray faint state, the emission occurs in a relatively small area (~ 10^16 cm) with relatively strong magnetic field (B~10^-1 G). The X-ray bright state shows a tendency opposite to that of the faint state, that is, a large emitting area (~10^18 cm), probably in the downstream of the jet and weak magnetic field (B~10^-3 G). The high X-ray flux was due to an increase in the maximum energy of electrons. On the other hand, the presence of two kinds of emitting areas implies that the one-zone model is unsuitable to reproduce, at least a part of the observed SEDs.

[16]  arXiv:2003.08067 [pdf, other]

Title: A Preferred Orientation Angle for Bipolar Planetary Nebulae

Authors: Andreas Ritter, Quentin A. Parker

Comments: conference proceedings WORKPLaNS2, held in Leiden (Netherlands) December 2019

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

We present preliminary results from measuring Galactic orientation angles of 800 elliptical and bipolar Planetary Nebulae (PNe) in the Hong Kong/Australian Astronomical Observatory/Strasbourg Observatory H-alpha Planetary Nebula (HASH) research platform and database (Parker et al. [1], [2]). For elliptical PNe the distribution of orientation angles is found to be essentially uniform. However, for bipolar PNe there is statistically significant evidence for preferred orientation angles (as tentatively reported before with smaller samples) across the whole Galaxy.

[17]  arXiv:2003.08075 [pdf, other]

Title: Dynamics of descending knots in a solar prominence and their possible contributions to the heating of the local corona

Authors: Yi Bi, Bo Yang, Tng Li, Yan Dong, Kaifan Ji

Comments: 13 pages, 6 figures

Journal-ref: published in 2020, ApJL, 891, L40

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

The knots in solar prominences are often observed to fall with nearly constant velocity, but the associated physical mechanism is currently not well understood. In this letter, we presented a prominence observed by New Vacuum Solar Telescope (NVST) in H-alpha wavelength. Knots that rose within the prominence appear to have been preferentially located at higher altitude, whereas those that fell were found throughout the entire prominence structure. The descending speed of the knots near the solar surface was higher than that far away from the solar surface. We noted that the knots near the solar surface may run along a set of coronal loops observed from the Atmospheric Imaging Assembly. Elsewhere, the majority of knots are interpreted to have descended across more horizontal magnetic field with a nearly constant speed. This lack of acceleration indicates that the liberated gravitational potential energy may not manifest as an increase in kinetic energy. Assuming instead that the descending knots were capable of exciting Alfven waves that could then dissipate within the local corona, the gravitational potential energy of the knots may have been converted into thermal energy. Assuming a perfectly elastic system, we therefore estimate that the gravitational energy loss rate of these observed knots amounts to 1/2000 of that required to heat the entire quiet-Sun, increasing to 1/320 when considering possibly further downward motions of the knots having disappeared in the H-alpha observations. This result suggests such a mechanism may contribute to the heating of the corona local to these prominences.

[18]  arXiv:2003.08103 [pdf]

Title: Impact Ejecta near the Impact Point Observed using Ultra-high-speed Imaging and SPH Simulations, and a Comparison of the Two Methods

Authors: Takaya Okamoto, Kosuke Kurosawa, Hidenori Genda, Takafumi Matsui

Comments: 33 pages, 16 figures, 1 supporting information, accepted for publication in Journal of Geophysical Research: Planets

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

High-speed impact ejecta at velocities comparable to the impact velocity are expected to contribute to material transport between planetary bodies and deposition of ejecta far from the impact crater. We investigated the behavior of high-speed ejecta produced at angles of 45 and 90 degrees, using both experimental and numerical methods. The experimental system developed at the Planetary Exploration Research Center of Chiba Institute of Technology (Japan) allowed us to observe the initial growth of the ejecta. We succeeded in imaging high-speed ejecta at 0.2 $\mathrm{{\mu}}$s intervals for impacts of polycarbonate projectiles of 4.8 mm diameter onto a polycarbonate plate at an impact velocity of ~4 km s$^{-1}$. Smoothed particle hydrodynamics (SPH) simulations of various numerical resolutions were conducted for the same impact conditions as pertaining to the experiments. We compared the morphology and velocities of the ejecta for the experiments and simulations, and we confirmed a close match for high-resolution simulations (with $\geq10^6$ SPH particles representing the projectile). According to the ejecta velocity distributions obtained from our high-resolution simulations, the ejection velocities of the high-speed ejecta for oblique impacts are much greater than those for vertical impacts. The translational motion of penetrating projectiles parallel to the target surface in oblique impacts could cause long-term, sustained acceleration at the root of the ejecta.

[19]  arXiv:2003.08131 [pdf, other]

Title: Various scenarios for the equatorward migration of sunspots

Authors: Detlef Elstner, Yori Fournier, Rainer Arlt

Comments: 4 pages, 4 figures

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

The profile of the differential rotation together with the sign of the alpha-effect determine the dynamo wave direction. In early models of the solar dynamo the dynamo wave often leads to a poleward migration of the activity belts. Flux transport by the meridional flow or the effect of the surface shear layer are possible solutions. In a model including the corona, we show that various migrations can be obtained by varying the properties of the corona. A new dynamo of Babcock-Leighton type also leads to the correct equatorward migration by the non-linear relation between flux density and rise time of the flux.

[20]  arXiv:2003.08133 [pdf, other]

Title: Enhancement of the tidal disruption event rate in galaxies with a nuclear star cluster: from dwarfs to ellipticals

Authors: Hugo Pfister, Marta Volonteri, Jane Lixin Dai, Monica Colpi

Comments: Submitted to MNRAS

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

We compute the tidal disruption event (TDE) rate around local massive black holes (MBHs) with masses as low as $2.5\times10^4\mathrm{ M}_\odot$, thus probing the dwarf regime for the first time. We select a sample of 37 galaxies for which we have the surface stellar density profile, a dynamical estimate of the mass of the MBH, and 6 of which, including our Milky Way, have a resolved nuclear star cluster (NSC). For the Milky Way, we find a total TDE rate of $\sim 10^{-4}\mathrm{ yr}^{-1}$ when taking the NSC in account, and $\sim 10^{-7} \mathrm{ yr}^{-1}$ otherwise. TDEs are mainly sourced from the NSC for light ($<3\times 10^{10}\mathrm{ M}_\odot$) galaxies, with a rate of few $10^{-5}\mathrm{ yr}^{-1}$, and an enhancement of up to 2 orders of magnitude compared to non-nucleated galaxies. We create a mock population of galaxies using different sets of scaling relations to explore trends with galaxy mass, taking into account the nucleated fraction of galaxies. Overall, we find a rate of few $10^{-5}\mathrm{ yr}^{-1}$ which drops when galaxies are more massive than $10^{11}\mathrm{ M}_\odot$ and contain MBHs swallowing stars whole and resulting in no observed TDE.

[21]  arXiv:2003.08169 [pdf, ps, other]

Title: Secular changes in the orbits of the quadruple system VW LMi

Authors: T. Pribulla, E. Puha, T. Borkovits, J. Budaj, Z. Garai, E. Guenther, L. Hambalek, R. Komzik, E. Kundra, Gy.M. Szabo, M. Vanko

Comments: 12 pages, 7 figures, MNRAS in press

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

VW~LMi is the tightest known quadruple system with 2+2 hierarchy. It consists of a W UMa-type eclipsing binary (P12 = 0.47755 days) and another detached non-eclipsing binary (P34 = 7.93 days) orbiting around a common center of mass is about P1234 = 355 days. We present new observations of the system extending the time baseline to study long-term perturbations in the system and to improve orbital elements. The multi-dataset modeling of the system (4 radial-velocity curves for the components and the timing data) clearly showed an apsidal motion in the non-eclipsing binary at a rate of 4.6 degrees/yr, but no other perturbations. This is consistent with the nearly co-planarity of the outer, 355-day orbit, and the 7.93-day orbit of the non-eclipsing binary. Extensive N-body simulations enabled us to constrain the mutual inclination of the non-eclipsing binary and the outer orbits to j34-1234 < 10 degrees.

[22]  arXiv:2003.08181 [pdf, ps, other]

Title: Studies of stationary features in jets: BL Lacertae. I. Dynamics and brightness asymmetry on sub-parsec scales

Authors: T.G. Arshakian, A.B. Pushkarev, M.L. Lister, M.H. Cohen, T. Savolainen

Comments: 17 pages, 21 figures, 1 table, submitted to A&A

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

Context. VLBA monitoring of BL Lacertae at 15 GHz reveals a quasi-stationary radio feature in the innermost part of the jet at 0.26 mas from the radio core. Stationary features are found in many blazars but have rarely been explored in detail. Aims. We aim to study the kinematics, dynamics, and brightness of the quasi-stationary feature of the jet in BL Lacertae based on the VLBA monitoring with submilliarcsecond resolution (subparsec-scales) over 17 years. Methods. We analyse position uncertainties and flux leakage effects of the innermost quasi-stationary feature and develop statistical tools to differentiate the motions of stationary feature and radio core. We construct a toy model to simulate the observed emission of the quasi-stationary component. Results. We find that trajectories of the quasi-stationary component are aligned along the jet axis, which can be interpreted as displacements of the radio core. During the jet stable state the core shift significantly influences the apparent displacements of the stationary component, which shows orbiting motion with reversals. The quasi-stationary component has low superluminal speeds on time scales of months, which is likely due to large positional errors. On time scales of years the apparent speeds are subrelativistic, of about 0.07 c. We find that the brightness profile of the quasi-stationary component is asymmetric along and transverse to the jet axis, and this effect remains unchanged with epoch. Conclusions. Accurate positional determination, high cadence of observations, and properly accounting for the core shift are crucial for measuring the trajectories and speeds of the quasi-stationary component. Its motion is similar to behaviour of the jet nozzle, which drags the outflow in a swinging motion and excites transverse waves of different amplitudes traveling downstream. (abbreviated)

[23]  arXiv:2003.08189 [pdf, other]

Title: Spirals inside the millimeter cavity of transition disk SR 21

Authors: G. A. Muro-Arena, C. Ginski, C. Dominik, M. Benisty, P. Pinilla, A. J. Bohn, T. Moldenhauer, W. Kley, D. Harsono, T. Henning, R. G. van Holstein, M. Janson, M. Keppler, F. Ménard, L. M. Pérez, T. Stolker, M. Tazzari, M. Villenave, A. Zurlo, C. Petit, F. Rigal, O. Möller-Nilsson, M. Llored, T. Moulin, P.Rabou

Comments: 7 pages, 4 figures

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

Hydrodynamical simulations of planet-disk interactions suggest that planets may be responsible for a number of the sub-structures frequently observed in disks in both scattered light and dust thermal emission. Despite the ubiquity of these features, direct evidence of planets embedded in disks and of the specific interaction features like spiral arms within planetary gaps still remain rare. In this study we discuss recent observational results in the context of hydrodynamical simulations in order to infer the properties of a putative embedded planet in the cavity of a transition disk. We imaged the transition disk SR 21 in H-band in scattered light with SPHERE/IRDIS and in thermal dust emission with ALMA band 3 (3mm) observations at a spatial resolution of 0.1". We combine these datasets with existing band 9 (430um) and band 7 (870um) ALMA continuum data. The Band 3 continuum data reveals a large cavity and a bright ring peaking at 53 au strongly suggestive of dust trapping.The ring shows a pronounced azimuthal asymmetry, with a bright region in the north-west that we interpret as a dust over-density. A similarly-asymmetric ring is revealed at the same location in polarized scattered light, in addition to a set of bright spirals inside the mm cavity and a fainter spiral bridging the gap to the outer ring. These features are consistent with a number of previous hydrodynamical models of planet-disk interactions, and suggest the presence of a ~1 MJup planet at 44 au and PA=11{\deg}. This makes SR21 the first disk showing spiral arms inside the mm cavity, as well as one for which the location of a putative planet can be precisely inferred. With the location of a possible planet being well-constrained by observations, it is an ideal candidate for follow-up observations to search for direct evidence of a planetary companion still embedded in its disk.

[24]  arXiv:2003.08205 [pdf]

Title: Rubidium transitions as wavelength reference for astronomical Doppler spectrographs

Authors: Dmytro Rogozin, Tobias Feger, Christian Schwab, Yulia V. Gurevich, Gert Raskin, David W. Coutts, Julian Stuermer, Andreas Seifahrt, Thorsten Fuehrer, Thomas Legero, Hans van Winckel, Sam Halverson, Andreas Quirrenbach

Comments: SPIE ANZCOP conference, Melbourne 2019

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

Precise wavelength calibration is a critical issue for high-resolution spectroscopic observations. The ideal calibration source should be able to provide a very stable and dense grid of evenly distributed spectral lines of constant intensity. A new method which satisfies all mentioned conditions has been developed by our group. The approach is to actively measure the exact position of a single spectral line of a Fabry-Perot etalon with very high precision with a wavelength-tuneable laser and compare it to an extremely stable wavelength standard. The ideal choice of standard is the D2 absorption line of Rubidium, which has been used as an optical frequency standard for decades. With this technique, the problem of stable wavelength calibration of spectrographs becomes a problem of how reliably we can measure and anchor one etalon line to the Rb transition. In this work we present our self-built module for Rb saturated absorption spectroscopy and discuss its stability.

[25]  arXiv:2003.08218 [pdf, other]

Title: Period spacings of gravity modes in rapidly rotating magnetic stars II. The case of an oblique dipolar fossil magnetic field

Authors: Vincent Prat, Stéphane Mathis, Coralie Neiner, Jordan Van Beeck, Dominic M. Bowman, Conny Aerts

Comments: 7 pages, 7 figures, accepted in A&A

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

Context. Stellar internal magnetic fields have recently been shown to leave a detectable signature on period spacing patterns of gravity modes.
Aims. We investigate the effect of the obliquity of a mixed (poloidal and toroidal) dipolar internal fossil magnetic field with respect to the rotation axis on the frequency of gravity modes in rapidly rotating stars.
Methods. We use the traditional approximation of rotation to compute non-magnetic modes, and a perturbative treatment of the magnetic field to compute the corresponding frequency shifts. We apply the new formalism to HD 43317, a magnetic, rapidly rotating, slowly pulsating B-type star, whose field has an obliquity angle of about 80{\deg}.
Results. We find that frequency shifts induced by the magnetic field on high-radial-order gravity modes are larger with increasing obliquity angle, when the magnetic axis is closer to the equatorial region, where these modes are trapped. The maximum value is reached for an obliquity angle of 90{\deg}. This trend is observed for all mode geometries.
Conclusions. Our results predict that the signature of an internal oblique dipolar magnetic field is detectable using asteroseismology of gravity modes.

[26]  arXiv:2003.08263 [pdf, other]

Title: Detecting outliers in astronomical images with deepgenerative networks

Authors: Berta Margalef-Bentabol, Marc Huertas-Company, Tom Charnock, Carla Margalef-Bentabol, Mariangela Bernardi, Yohan Dubois, Kate Storey-Fisher, Lorenzo Zanis

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

With the advent of future big-data surveys, automated tools for unsupervised discovery are becoming ever more necessary. In this work, we explore the ability of deep generative networks for detecting outliers in astronomical imaging datasets. The main advantage of such generative models is that they are able to learn complex representations directly from the pixel space. Therefore, these methods enable us to look for subtle morphological deviations which are typically missed by more traditional moment-based approaches. We use a generative model to learn a representation of \emph{expected} data defined by the training set and then look for deviations from the learned representation by looking for the best reconstruction of a given object. In this first proof-of-concept work, we apply our method to two different test cases. We first show that from a set of simulated galaxies, we are able to detect $\sim90\%$ of merging galaxies if we train our network only with a sample of isolated ones. We then explore how the presented approach can be used to compare observations and hydrodynamic simulations by identifying observed galaxies not well represented in the models.

[27]  arXiv:2003.08266 [pdf, ps, other]

Title: Gamma-Ray Flares in Long Term Light Curve of 3C 454.3

Authors: Avik Kumar Das, Raj Prince, Nayantara Gupta

Comments: 51 pages, 55 figures, 34 tables, Accepted for Publication in ApJS

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

3C 454.3 is frequently observed in flaring state. The long term light curve of this source has been analysed with 9 year (August 2008 - July 2017) data from Fermi LAT detector. We have identified five flares and one quiescent state. The flares have sub-structures with many peaks during flaring phase. We have estimated the rise and decay time of the flares and compared with flares of other similar sources. The modeling of gamma ray spectral energy distributions shows in most cases Log parabola function gives the best fit to the data. We have done time dependent leptonic modeling of two of the flares, for which simultaneous multi-wavelength data are available. These two long lasting flares Flare-2A and Flare-2D continued for 95 days and 133 days respectively. We have used the average values of Doppler factor, injected luminosity in electrons, size of the emission region and the magnetic field in the emission region in modeling these flares. The emission region is assumed to be in the broad line region in our single zone model. The energy losses (synchrotron, synchrotron self-Compton, external Compton) and escape of electrons from the emission region have been included while doing the modelling. Although, the total jet powers required to model these flares with leptonic model are higher compared to other sources, they are always found to be lower than the Eddington's luminosity of 3C 454.3. We also select some flaring peaks and show that time variation of the Doppler factor or the injected luminosity in electrons over short time scales can explain their light curves.

[28]  arXiv:2003.08277 [pdf, other]

Title: Blinded challenge for precision cosmology with large-scale structure: results from effective field theory for the redshift-space galaxy power spectrum

Authors: Takahiro Nishimichi, Guido D'Amico, Mikhail M. Ivanov, Leonardo Senatore, Marko Simonović, Masahiro Takada, Matias Zaldarriaga, Pierre Zhang

Comments: 23 pages, 12 figures, participation in the challenge welcome, mock data available at this https URL

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

An accurate theoretical template for the galaxy power spectrum is a key for the success of ongoing and future spectroscopic surveys. We examine to what extent the Effective Field Theory of Large Scale Structure is able to provide such a template and correctly estimate cosmological parameters. To that end, we initiate a blinded challenge to infer cosmological parameters from the redshift-space power spectrum of high-resolution mock catalogs mimicking the BOSS galaxy sample but covering a hundred times larger cumulative volume. This gigantic simulation volume allows us to separate systematic bias due to theoretical modeling from the statistical error due to sample variance. The challenge task was to measure three unknown input parameters used in the simulation: the Hubble constant, the matter density fraction, and the clustering amplitude. We present analyses done by two independent teams, who have fitted the mock simulation data generated by yet another independent group. This allows us to avoid any confirmation bias by analyzers and pin down possible tuning of the specific EFT implementations. Both independent teams have recovered the true values of the input parameters within sub-percent statistical errors corresponding to the total simulation volume.

[29]  arXiv:2003.08313 [pdf, other]

Title: Wave Dark Matter and Ultra Diffuse Galaxies

Authors: Alvaro Pozo, Tom Broadhurst, Ivan De Martino, Hoang Nhan Luu, George F. Smoot, Jeremy Lim, Mark Neyrinck

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

Dark matter as a Bose-Einstein condensate, such as the axionic scalar field particles of String Theory, can explain the coldness of dark matter on large scales. Pioneering simulations in this context predict a rich wave-like structure, with a ground state soliton core in every galaxy surrounded by a halo of excited states that interfere on the de Broglie scale. This de Broglie scale is largest for low mass galaxies as momentum is lower, providing a simple explanation for the wide cores of dwarf spheroidal galaxies. Here we extend these "wave dark matter" ($\psi$DM) predictions to the newly discovered class of "Ultra Diffuse Galaxies" (UDG) that resemble dwarf spheroidal galaxies but with more extended stellar profiles. Currently the best studied example, DF44, has a uniform velocity dispersion of $\simeq 33$km/s, extending to a least 3 kpc, that we show is reproduced by our $\psi$DM simulations with a soliton radius of $\simeq 0.5$ kpc. In the $\psi$DM context, we show the relatively flat dispersion profile of DF44 lies between massive galaxies with compact dense solitons, as may be present in the Milky Way on a scale of 100pc and lower mass galaxies where the velocity dispersion declines centrally within a wide, low density soliton, like Antlia II, of radius 3Kpc. In contrast, standard CDM requires excessive tangential stellar motions predominate to counter the inherent central cusp which would otherwise enhance the central velocity dispersion.

[30]  arXiv:2003.08352 [pdf, other]

Title: The LBT Satellites of Nearby Galaxies Survey (LBT-SONG): The Satellite Population of NGC 628

Authors: A. Bianca Davis, Anna M. Nierenberg, Annika H. G. Peter, Christopher T. Garling, Johnny P. Greco, Christopher S. Kochanek, Dyas Utomo, Kirsten Casey, Richard W. Pogge, Daniella Roberts, David J. Sand, Amy Sardone

Comments: 17 pages, 11 figures

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

We present the first satellite system of the Large Binocular Telescope Satellites Of Nearby Galaxies Survey (LBT-SONG), a survey to characterize the close satellite populations of Large Magellanic Cloud to Milky Way-mass, star-forming galaxies in the Local Volume. In this paper, we describe our satellite finding and completeness measurement methodology and apply this framework to NGC 628, an isolated galaxy with ~1/4 the stellar mass of the Milky Way. We present two new dwarf satellite galaxy candidates: NGC 628 dwA, and dwB with $\text{M}_{\text{V}}$ = $-12.2$ and $-7.7$, respectively. NGC 628 dwA is a classical dwarf while NGC 628 dwB is a low-luminosity galaxy that appears to have been quenched after reionization. Completeness corrections indicate that the presence of these two satellites is consistent with CDM predictions. The satellite colors indicate that the galaxies are neither actively star-forming nor do they have the purely ancient stellar populations characteristic of ultrafaint dwarfs. Instead, and consistent with our previous work on the NGC 4214 system, they show signs of recent quenching, further indicating that environmental quenching can play a role in modifying satellite populations even for hosts smaller than the Milky Way.

Cross-lists for Thu, 19 Mar 20

[31]  arXiv:2003.07360 (cross-list from hep-ph) [pdf, other]

Title: Gravitational waves from first-order cosmological phase transitions: lifetime of the sound wave source

Authors: John Ellis, Marek Lewicki, José Miguel No

Comments: 32 pages, 14 figures

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

We study particle-physics models for a first-order phase transition in the early universe, including models with polynomial potentials both with and without barriers at zero temperature, and Coleman-Weinberg-like models with potentials that are classically scale-invariant. We distinguish three possibilities for the transition - detonations, deflagrations and hybrids - and consider sound waves and turbulent mechanisms for generating gravitational waves during the transitions in these models. We argue that in models without a zero-temperature barrier and in scale-invariant models the period during which sound waves generate gravitational waves lasts only for a fraction of a Hubble time after a generic first-order cosmological phase transition, whereas it may last longer in some models with a zero-temperature barrier that feature severe supercooling. We illustrate the implications of these results for future gravitational-wave experiments.

[32]  arXiv:2003.07363 (cross-list from hep-ph) [pdf, other]

Title: Axion Quark Nuggets. SkyQuakes and Other Mysterious Explosions

Authors: Dmitry Budker, Victor V. Flambaum, Ariel Zhitnitsky

Comments: 15 pages, 4 figures

Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Earth and Planetary Astrophysics (astro-ph.EP); Atmospheric and Oceanic Physics (physics.ao-ph); Geophysics (physics.geo-ph)

We advocate an idea that some mysterious explosions, the so-called sky-quakes, which have been known for centuries could be a manifestation of the dark matter Axion Quark Nuggets (AQN) when they propagate in the Earth's atmosphere. We specifically study the event which occurred on July 31-st 2008 and was properly recorded by the dedicated Elginfield Infrasound Array (ELFO) near London, Ontario, Canada. The infrasound detection was accompanied by non-observation of any meteors by an all-sky camera network. Our interpretation is based on the AQN dark matter model which was originally invented with a completely different purpose---to explain the similarity of the dark and visible cosmological matter densities $\Omega_{\rm dark}\sim \Omega_{\rm visible}$. Our estimates for the infrasonic frequency $\nu\simeq 5$ Hz and overpressure $\delta p\sim 0.3$ Pa are consistent with the ELFO record. We propose a detection strategy for a systematic study to search for such explosions originating from AQNs by using Distributed Acoustic Sensing and briefly mention other possible detection methods. Specific signals from AQN tracks may also be detected by an existing network of seismic stations.

[33]  arXiv:2003.08079 (cross-list from nucl-th) [pdf, ps, other]

Title: Cooling of hybrid neutron stars with microscopic equations of state

Authors: J.-B. Wei, G. F. Burgio, H.-J. Schulze, and D. Zappalà

Comments: 10 pages, 6 figures

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

We model the cooling of hybrid neutron stars combining a microscopic nuclear equation of state in the Brueckner-Hartree-Fock approach with different quark models. We then analyze the neutron star cooling curves predicted by the different models and single out the preferred ones. We find that the possibility of neutron p-wave pairing can be excluded in our scenario.

[34]  arXiv:2003.08092 (cross-list from physics.hist-ph) [pdf, other]

Title: The determination of stellar temperatures from Baron B. Harkányi to the Gaia mission

Authors: Kristof Petrovay

Comments: 10 pages, 2 figures, 1 table. Journal for the History of Astronomy, in press (May 2020 issue)

Subjects: History and Philosophy of Physics (physics.hist-ph); Solar and Stellar Astrophysics (astro-ph.SR)

The first determination of the surface temperature of stars other than the Sun is due to the Hungarian astrophysicist B\'ela Hark\'anyi. Prompted by the recent unprecedented increase in the availability of stellar temperature estimates from Gaia, coinciding with the 150th anniversary of Hark\'anyi's birth, this article presents the life and work of this neglected, yet remarkable figure in the context of the history of stellar astrophysics.

[35]  arXiv:2003.08199 (cross-list from hep-ph) [pdf, other]

Title: Thermal Evolution of Neutron Stars as a Probe of Physics beyond the Standard Model

Authors: Keisuke Yanagi

Comments: Dissertation submitted to Department of Physics, University of Tokyo (Dec. 2019). 117 pages. Based on arXiv:1806.07151, arXiv:1904.04667 and arXiv:1905.02991. The code used in chapter 4 and 5 is available at this https URL

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

Thermal evolution of neutron stars (NSs) is studied as a probe of physics beyond the standard model. We first review the standard cooling theory of NSs in detail, with an emphasis on the roles of nucleon superfluidity. Then we discuss non-standard evolution with axion and dark matter (DM); axion production enhances the cooling while DM accretion leads to heating of NSs. To evaluate the effect of DM heating, we need to compare it to the rotochemical heating, which is caused by the out-of-equilibrium beta processes in a NS. In the dissertation, we also investigate the rotochemical heating in the presence of both neutron and proton superfluidity.

[36]  arXiv:2003.08213 (cross-list from physics.ins-det) [pdf]

Title: Radiation damage assessment of SensL SiPMs

Authors: Lee J. Mitchell, Bernard Phlips, W. Neil Johnson, Mary Johnson-Rambert, Anika N. Kansky, Richard Woolf

Comments: 36 pages, 49 Figures, To be presented at the Nuclear and Space Radiation Effects Conference (NSREC 2020)

Subjects: Instrumentation and Detectors (physics.ins-det); Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Experiment (hep-ex)

Silicon Photomultipliers (SiPMs) are quickly replacing traditional photomultiplier tubes (PMTs) as the readout of choice for gamma-ray scintillation detectors in space. While they offer substantial size, weight and power saving, they have shown to be susceptible to radiation damage. SensL SiPMs with different cell sizes were irradiated with 64 MeV protons and 8 MeV electrons. In general, results show larger cell sizes are more susceptible to radiation damage with the largest 50 um SiPMs showing the greatest increase in current as a function of dose. Current increases were observed for doses as low at ~2 rad(Si) for protons and ~20 rad(Si) for electrons. The U.S. Naval Research Laboratory's (NRL) Strontium Iodide Radiation Instrument (SIRI-1) experienced a 528 uA increase in the bias current of the on-board 2x2 SensL J-series 60035 SiPM over its one-year mission in sun-synchronous orbit. The work here focuses on the increase in bulk current observed with increasing radiation damage and was performed to better quantify this effect as a function of dose for future mission. These include the future NRL mission SIRI-2, the follow on to SIRI-1, Glowbug and the GAGG Radiation Instrument (GARI).

[37]  arXiv:2003.08244 (cross-list from gr-qc) [pdf, ps, other]

Title: A comment on "Lense-Thirring frame dragging induced by a fast-rotating white dwarf in a binary pulsar system" by V. Venkatraman Krishnan et al

Authors: Lorenzo Iorio

Comments: LaTex2e, 21 pages, 3 figures, no tables. Due to arXiv's space limitations, low-resolution pictures have been upoloaded

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

We comment on a recent study reporting an alleged evidence for the general relativistic Lense-Thirring secular precession of the inclination $I$ of the orbital plane to the plane of the sky of the tight binary system PSR J1141-6545 made of a white dwarf and an emitting radiopulsar of comparable masses. The quadrupole mass moment $Q_2^\mathrm{c}$ and the angular momentum ${\boldsymbol S}^\mathrm{c}$ of the white dwarf cause the detectable effects on $I$ with respect to the present-day accuracy in the pulsar's timing. The history-dependent and model-dependent assumptions to be made on $Q_2^\mathrm{c}$ and ${\boldsymbol S}^\mathrm{c}$, required even just to calculate the analytical expressions for the resulting post-Keplerian precessions, are too wide in order to claim a successful test of the Einsteinian gravitomagnetic effect. Moreover, depending on how $Q_2^\mathrm{c}$ is calculated, the competing quadrupole-induced rate of change, which is a major source of systematic uncertainty, may be up to $\lesssim 30-50\%$ of the Lense-Thirring effect for most of the allowed values in the 3D parameter space spanned by the white dwarf's spin period $P_\mathrm{s}$, and the polar angles $i_\mathrm{c},\,\zeta_\mathrm{c}$ of its spin axis. The possible use of the longitude of periastron $\dot\varpi$ is investigated as well. It turns out that a measurement of its secular precession, caused, among other things, also by $Q_2^\mathrm{c},\,{\boldsymbol{S}}^\mathrm{c}$, could help in further restricting the permitted regions in the white dwarf's parameter space.

[38]  arXiv:2003.08328 (cross-list from gr-qc) [pdf, ps, other]

Title: The Logotropic Dark Fluid: Observational and Thermodynamic Constraints

Authors: Abdulla Al Mamon, Subhajit Saha

Comments: 10 pages, 5 figures, Comments welcome

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

We have considered a FLRW Universe filled with a single fluid, known as logotropic dark fluid (LDF), whose pressure evolves through a logarithmic equation of state. We use the latest Hubble data to constrain the parameters of this model, the present fraction of dark matter Omega_{m0} and the Hubble constant H_0. We find that the best-fit values of these parameters are Omega_{m0}=0.253 and H_{0}=70.35 kms^{-1}Mpc^{-1}, which is approximately the mean value of the global and local measurements of H_0 at the 1sigma C.L. The best-fit values obtained from this dataset are then applied to examine the evolutionary history of the logotropic equation of state and the deceleration parameter. Our study shows that the Universe is indeed undergoing an accelerated expansion phase following the decelerated one. We also measure the redshift of this transition (i.e., the cosmological deceleration-acceleration transition) z_t=0.81 and is well consistent with the present observations. Interestingly, we find that the Universe will settle down to a LCDM model in future and there will not be any future singularity in the LDF model. Furthermore, we compare the LDF and LCDM models. We notice that there is no significant difference between the LDF and LCDM models at the present epoch, but the difference (at the percent level) between these models is found as the redshift increases. These dynamical features of the LDF can be effective in determining the late-time evolution of the Universe and thus may provide an answer to the coincidence problem. We have also studied the generalized second law of thermodynamics at the dynamical apparent horizon for the LDF model with the Bekenstein and Viaggiu entropies. Our analysis has yielded a thermodynamically allowable range for the parameter B, 0 leq B leq 0.339, thereby supporting the value, B=3.53 \times 10^{-3} obtained by Chavanis from galactic observations[16].

Replacements for Thu, 19 Mar 20

[39]  arXiv:1901.08881 (replaced) [pdf, ps, other]

Title: Deconstructing double-barred galaxies in 2D and 3D. II. Two distinct groups of inner bars

Authors: A. de Lorenzo-Cáceres (1, 2 and 3), J. Méndez-Abreu (1, 2 and 3), B. Thorne (1 and 4), L. Costantin (5 and 6) ((1) University of St Andrews, UK, (2) Instituto de Astrofísica de Canarias, Spain, (3) Universidad de La Laguna, Spain, (4) University of California, USA, (5) Centro de Astrobiología, Spain, (6) Osservatorio Astronomico di Brera, Italy)

Comments: 14 pages, 8 figures, 1 table. Accepted for publication in MNRAS

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

[40]  arXiv:1902.07108 (replaced) [pdf, other]

Title: Imprints of an extended Chevallier-Polarski-Linder parametrization on the large scale of our universe

Authors: Supriya Pan, Weiqiang Yang, Andronikos Paliathanasis

Comments: 17 pages, 12 captioned figures, 8 tables, accepted for publication by EPJC

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

[41]  arXiv:1904.11508 (replaced) [pdf, other]

Title: A profile in FIRE: resolving the radial distributions of satellite galaxies in the Local Group with simulations

Authors: Jenna Samuel, Andrew Wetzel, Erik Tollerud, Shea Garrison-Kimmel, Sarah Loebman, Kareem El-Badry, Philip F. Hopkins, Michael Boylan-Kolchin, Claude-Andre Faucher-Giguere, James S. Bullock, Samantha Benincasa, Jeremy Bailin

Comments: 18 pages, 10 figures, plus appendices. Main results in figures 2, 3, and 4. Accepted version

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

[42]  arXiv:1905.08177 (replaced) [pdf, ps, other]

Title: An issue with the classification of the scalar-tensor theories of gravity

Authors: Israel Quiros, Roberto De Arcia, Ricardo García-Salcedo, Tame Gonzalez, Francisco Antonio Horta-Rangel

Comments: 22 pages, no figures. Version that matches the one accepted by the IJMPD. arXiv admin note: substantial text overlap with arXiv:1901.08690

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

[43]  arXiv:1907.04331 (replaced) [pdf, other]

Title: Target Neutrino Mass Precision for Determining the Neutrino Hierarchy

Authors: Constance Mahony, Boris Leistedt, Hiranya V. Peiris, Jonathan Braden, Benjamin Joachimi, Andreas Korn, Linda Cremonesi, Ryan Nichol

Comments: v3: Version accepted in Phys Rev D. Minor clarifications and added robustness tests, conclusions unchanged

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

[44]  arXiv:1907.10557 (replaced) [pdf, other]

Title: Maximum likelihood estimation for disk image parameters

Authors: Matwey V. Kornilov

Comments: 13 pages, 4 figures

Subjects: Image and Video Processing (eess.IV); Instrumentation and Methods for Astrophysics (astro-ph.IM); Computer Vision and Pattern Recognition (cs.CV)

[45]  arXiv:1907.13152 (replaced) [pdf, other]

Title: A Volume Limited Sample of Cataclysmic Variables from $\mathit{Gaia}$ DR2: Space Density and Population Properties

Authors: A. F. Pala, B. T. Gänsicke, E. Breedt, C. Knigge, J. J. Hermes, N. P. Gentile Fusillo, M. A. Hollands, T. Naylor, I. Pelisoli, M. R. Schreiber, S. Toonen, A. Aungwerojwit, E. Cukanovaite, E. Dennihy, C. J. Manser, M. L. Pretorius, S. Scaringi, O. Toloza

Comments: Updated version after the review process. Now accepted for publication in MNRAS

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

[46]  arXiv:1909.07981 (replaced) [pdf, other]

Title: Constraining Dark-Matter Ensembles with Supernova Data

Authors: Aditi Desai, Keith R. Dienes, Brooks Thomas

Comments: 10 pages, LaTeX, 2 figures

Journal-ref: Phys. Rev. D 101, 035031 (2020)

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

[47]  arXiv:1910.03797 (replaced) [pdf, other]

Title: Predicting the next local supernova

Authors: John Middleditch (University of California, retired)

Comments: 10 pages, 1 figure

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

[48]  arXiv:1910.07525 (replaced) [pdf, other]

Title: Minimal Warm Inflation

Authors: Kim V. Berghaus, Peter W. Graham, David E. Kaplan

Comments: 18 pages, 1 figure, v2: We added additional references and clarifying comments in the introduction. We added an estimate on thermalization in section III, and an additional comment on cosine-like potentials in section IV, and a footnote commenting on equation 12. v2 matches published version

Journal-ref: JCAP03(2020)034

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

[49]  arXiv:1910.08821 (replaced) [pdf, other]

Title: Dark calling Dark: Interaction in the dark sector in presence of neutrino properties after Planck CMB final release

Authors: Weiqiang Yang, Supriya Pan, Rafael C. Nunes, David F. Mota

Comments: 13 pages, 6 tables (3 tables in the main text and 3 tables in the appendix), 3 captioned figures; accepted for publication in JCAP

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

[50]  arXiv:1912.06369 (replaced) [pdf, ps, other]

Title: What constraints on the neutron star maximum mass can one pose from GW170817 observations?

Authors: Shunke Ai, He Gao, Bing Zhang

Comments: 12 pages, 4 figures, Accepted for publication on The Astrophysical Journal

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

[51]  arXiv:1912.07795 (replaced) [pdf, other]

Title: Direct detection rate of heavy Higgsino-like and Wino-like dark matter

Authors: Qing Chen, Richard J. Hill

Comments: matches published version, one reference added, nuclear effect discussion promoted to a separate section, minor text changes

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

[52]  arXiv:1912.08700 (replaced) [pdf, other]

Title: BAL and non-BAL quasars: continuum, emission and absorption properties establish a common parent sample

Authors: Amy L. Rankine, Paul C. Hewett, Manda Banerji, Gordon T. Richards

Comments: 22 pages, 18 figures, plus Appendices. Minor changes to reflect published version in MNRAS

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

[53]  arXiv:1912.10354 (replaced) [pdf, other]

Title: The Broad-lined Ic Supernova ZTF18aaqjovh (SN 2018bvw): An Optically-discovered Engine-driven Supernova Candidate with Luminous Radio Emission

Authors: Anna Y. Q. Ho (1), Alessandra Corsi (2), S. Bradley Cenko (3 and 4), Francesco Taddia (5), S. R. Kulkarni (1), Scott Adams (1), Kishalay De (1), Richard Dekany (6), Dmitry D. Frederiks (7), Christoffer Fremling (1), V. Zach Golkhou (8 and 9), Thomas Kupfer (10), Russ R. Laher (11), Ashish Mahabal (1 and 12), Frank J. Masci (11), Adam A. Miller (13 and 14), James D. Neill (6), Daniel Reiley (6), Reed Riddle (6), Anna Ridnaia (7), Ben Rusholme (11), Yashvi Sharma (1), Jesper Sollerman (5), Maayane T. Soumagnac (15 and 16), Dmitry S. Svinkin (7), David L. Shupe (11) ((1) Cahill Center for Astrophysics, Caltech, (2) Texas Tech University, (3) NASA Goddard, (4) University of Maryland, (5) Stockholm University, (6) Caltech Optical Observatories, (7) Ioffe Institute, (8) DIRAC Institute, University of Washington, (9) The eScience Institute, University of Washington, (10) Kavli Institute for Theoretical Physics, UCSB, (11) IPAC, Caltech, (12) Center for Data Driven Discovery, Caltech, (13) CIERA, Northwestern, (14) Adler Planetarium, (15) LBNL, (16) Weizmann Institute of Science)

Comments: 17 pages, 8 figures. Accepted to the Astrophysical Journal on 2 March 2020

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

[54]  arXiv:2002.08381 (replaced) [pdf, ps, other]

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

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

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

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

[55]  arXiv:2002.10762 (replaced) [pdf, other]

Title: Fourth-order Coronagraph for High-Contrast Imaging of Exoplanets with Off-axis Segmented Telescopes

Authors: Satoshi Itoh, Taro Matsuo

Comments: Accepted for Publication in The Astronomical Journal

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

[56]  arXiv:2002.11126 (replaced) [pdf, other]

Title: The Satellite Luminosity Function of M101 into the Ultra-Faint Dwarf Galaxy Regime

Authors: P. Bennet, D. J. Sand, D. Crnojevic, K. Spekkens, A. Karunakaran, D. Zaritsky, B. Mutlu-Pakdil

Comments: 9 Pages, 3 Figures, 1 Table, Accepted by ApJL

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

[57]  arXiv:2002.12673 (replaced) [pdf, ps, other]

Title: The Spatial Evolution of Young Massive Clusters II. Looking for Imprints of Star Formation in NGC 2264 with Gaia DR2

Authors: Anne S.M. Buckner, Zeinab Khorrami, Marta Gonzalez, Stuart L. Lumsden, Estelle Moraux, Rene D. Oudmaijer, Paul Clark, Isabelle Joncour, Jose Manuel Blanco, Ignacio de la Calle, Alvaro Hacar, Jose M. Herrera-Fernandez, Frederique Motte, Jesus Salgado, Luis Valero-Martin

Comments: 13 pages, 4 figures, 5 tables, Accepted for publication in A&A

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

[58]  arXiv:2003.01222 (replaced) [pdf, other]

Title: The Koala: A Fast Blue Optical Transient with Luminous Radio Emission from a Starburst Dwarf Galaxy at $z=0.27$

Authors: Anna Y. Q. Ho (1), D. A. Perley (2) S. R. Kulkarni (1), I. Andreoni (1), E. C. Bellm (3), K. B. Burdge (1), P. Chandra (4), M. Coughlin, K. De (1), D. Z. J. Dong (1), V. Z. Golkhou (3,6,7), M. J. Graham (1), D. D. Fredericks (8), G. Helou (9), A. Horesh (10), R. R. Laher (9), F. Masci (9), A. Ridnaia (8), B. Rusholme (9), D. L. Shupe (9), D. S. Svinkin (8) ((1) Caltech, (2) LJMU, (3) DIRAC Institute, UW, (4) NCRA, (5) U. Minnesota, (6) eScience Institute, (7) Moore-Sloan, WRF Innovation, DIRAC Fellow, (8) Ioffe Institute, (9) IPAC, (10) Racah Institute)

Comments: 21 pages, 10 figures. Submitted to ApJ on 2 March 2020. Updated with additional co-authors and acknowledgements on 18 March. Comments welcome!

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

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