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Gravitational wave signature from phase transition of a combusting neutron star to quark star Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-08-02 Mallick R, Singh S, Prasad R.
AbstractFluctuation at the neutron star center gives rise to a small deconfined quark core very close to the star center. The density discontinuity at the quark-hadron boundary initiates a shock wave, which propagates outwards of the star. The shock has enough energy to combust nuclear matter to 2-flavor quark matter in the star. The 2-flavor quark matter is not stable and settles to a stable 3-flavor
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Global simulations of tidal disruption event disk formation via stream injection in GRRMHD Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-08-02 Curd B.
AbstractWe use the general relativistic radiation magnetohydrodynamics code KORAL to simulate the accretion disk formation resulting from the tidal disruption of a solar mass star around a super massive black hole (BH) of mass 106 M⊙. We simulate the disruption of artificially more bound stars with orbital eccentricity e ≤ 0.99 (compared to the more realistic case of parabolic orbits with e = 1) on
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Orientation effect on the light curve shape of periodic methanol maser sources Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-08-02 Morgan J, van der Walt D, Chibueze J, et al.
AbstractWe report the results of our pilot millimeter observations of periodic maser sources. Using SMA, we carried out 1.3 mm observations of G22.357+0.066 and G25.411+0.105, while ALMA 1.3 mm archival data was used in the case of G9.62+0.19E. Two continuum cores (MM1 and MM2) were detected in G22.357+0.066, while 3 cores (MM1 – MM3) detected in G25.411+0.105. Assuming dust-to-gas ratio of 100, we
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How does the shape of gamma-ray bursts’ pulses affect the duration distribution? Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-08-02 Tarnopolski M.
AbstractGamma-ray bursts (GRBs) come in two types, short and long. The distribution of logarithmic durations of long GRBs is asymmetric rather than Gaussian. Such an asymmetry, when modelled with a mixture of Gaussian distributions, requires an introduction of an additional component, often associated with another class of GRBs. However, when modelled with inherently asymmetric distributions, there
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Intra-day multi-band optical variability of BL Lacertae object S5 0716+714 Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-08-02 Yan Dai, Yue Fang, Xiaoyuan Zhang, Nankun Meng, Jianghua Wu, Zong-Hong Zhu
We monitored the BL Lac object S5 0716+714 in four optical wavebands with four telescopes on 11 nights from 2012 to 2017. The object was active during most of those nights. It was brightest on 2012 November 07 with 11.720 mags in the I band and reached the faintest state on 2016 January 22 with 15.770 mags in the R band corresponding to ∼15.230 mags in the I band. Intraday variations in all bands were
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Spectroscopic modelling of two high-mass X-ray binaries, Cyg X–3 and 4U 1538–522 Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-08-02 Gargi Shaw, Sudip Bhattacharyya
We report a detailed modelling of soft X-ray emission lines from two stellar-wind fed Galactic high mass X-ray binary (HMXB) systems, Cyg X-3 and 4U 1538-522, and estimate physical parameters, e.g. hydrogen density, radiation field, chemical abundances, wind velocity, etc. The spectral synthesis code CLOUDY is utilized for this modelling. We model highly ionised X-ray spectral lines such as Fe XXV
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Impact of gas-based seeding on supermassive black hole populations at z ≥ 7 Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-08-02 Aklant K Bhowmick, Laura Blecha, Paul Torrey, Luke Zoltan Kelley, Mark Vogelsberger, Kaitlyn Kosciw, Dylan Nelson, Rainer Weinberger, Lars Hernquist
Deciphering the formation of supermassive black holes (SMBHs) is a key science goal for upcoming observational facilities. In many theoretical channels proposed so far, the seed formation depends crucially on local gas conditions. We systematically characterize the impact of a range of gas-based black hole seeding prescriptions on SMBH populations using cosmological simulations. Seeds of mass Mseed
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The HI angular momentum-mass relation Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-08-02 Sushma Kurapati, Jayaram N Chengalur, Marc A W Verheijen
We study the relationship between the H i specific angular momentum (|$\rm j_{g}$|) and the H i mass (|$\rm M_{g}$|) for a sample of galaxies with well measured H i rotation curves. We find that the relation is well described by an unbroken power law |$\rm j_{g}$|∝ |$\rm M_{g}$|α over the entire mass range (107 – 1010.5 M⊙), with α = 0.89 ± 0.05 (scatter 0.18 dex). This is in reasonable agreement
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Probing the kinematics and chemistry of the hot core Mon R 2 IRS 3 using ALMA observations Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-08-02 Fuente A, Treviño-Morales S, Alonso-Albi T, et al.
AbstractWe present high angular resolution 1.1mm continuum and spectroscopic ALMA observations of the well-known massive proto-cluster Mon R 2 IRS 3.The continuum image at 1.1mm shows two components, IRS 3 A and IRS 3 B, that are separated by ∼0.65″. We estimate that IRS 3 A is responsible of ∼80 per cent of the continuum flux, being the most massive component. We explore the chemistry of IRS 3 A based
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Stability of superthermal strahl electrons in the solar wind Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-08-02 Schroeder J, Boldyrev S, Astfalk P.
AbstractWe present a kinetic stability analysis of the solar wind electron distribution function consisting of the Maxwellian core and the magnetic-field aligned strahl, a superthermal electron beam propagating away from the sun. We use an electron strahl distribution function obtained as a solution of a weakly collisional drift-kinetic equation, representative of a strahl affected by Coulomb collisions
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Jupiter’s X-ray aurora during UV dawn storms and injections as observed by XMM-Newton, Hubble, and Hisaki Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-08-02 A D Wibisono, G Branduardi-Raymont, W R Dunn, T Kimura, A J Coates, D Grodent, Z H Yao, H Kita, P Rodriguez, G R Gladstone, B Bonfond, R P Haythornthwaite
We present results from a multiwavelength observation of Jupiter’s northern aurorae, carried out simultaneously by XMM-Newton, the Hubble Space Telescope (HST), and the Hisaki satellite in September 2019. HST images captured dawn storms and injection events in the far ultraviolet aurora several times during the observation period. Magnetic reconnection occurring in the middle magnetosphere caused by
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Modes of a stellar system I: ergodic systems Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-08-02 Lau J, Binney J.
AbstractThe excursions of star clusters and galaxies around statistical equilibria are studied. For a stable ergodic model Antonov’s Hermitian operator on six-dimensional phase space has the normal modes as its eigenfunctions. The excitation energy of the system is just the sum of the (positive) energies associated with each normal mode. Formulae are given for the DFs of modes, which are of the type
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Outliers in the LIGO black hole mass function from coagulation in dense clusters Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-08-02 Flitter J, Muñoz J, Kovetz E.
AbstractThe advanced LIGO O3a run catalog has been recently published, and it includes several events with unexpected mass properties, including mergers with individual masses in the lower and upper mass gaps, as well as mergers with unusually small mass ratios between the binary components. Here we entertain the possibility that these outliers are the outcome of hierarchical mergers of black holes
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HD 183579b: A Warm Sub-Neptune Transiting a Solar Twin Detected by TESS Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-08-02 Tianjun Gan, Megan Bedell, Sharon Xuesong Wang, Daniel Foreman-Mackey, Jorge Meléndez, Shude Mao, Keivan G Stassun, Steve B Howell, Carl Ziegler, Robert A Wittenmyer, Coel Hellier, Karen A Collins, Avi Shporer, George R Ricker, Roland Vanderspek, David W Latham, Sara Seager, Joshua N Winn, Jon M Jenkins, Brett C Addison, Sarah Ballard, Thomas Barclay, Jacob L Bean, Brendan P Bowler, César Briceño,
We report the discovery and characterization of a transiting warm sub-Neptune planet around the nearby bright (V = 8.75 mag, K = 7.15 mag) solar twin HD 183579, delivered by the Transiting Exoplanet Survey Satellite (TESS). The host star is located 56.8 ± 0.1 pc away with a radius of R* = 0.97 ± 0.02 R⊙ and a mass of M* = 1.03 ± 0.05 M⊙. We confirm the planetary nature by combining space and ground-based
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On the angular momentum extraction from the rotation powered pulsars Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-08-02 Shibata S, Kisaka S.
AbstractThe rotation powered pulsar loses angular momentum at a rate of the rotation power divided by the angular velocity Ω*. This means that the length of the lever arm of the angular momentum extracted by the photons, relativistic particles and wind must be on average c/Ω*, which is known as the light cylinder radius. Therefore, any deposition of the rotation power within the light cylinder causes
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Global Three-Dimensional Simulations of Outer Protoplanetary Disks with Ambipolar Diffusion Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-08-02 Cui C, Bai X.
AbstractThe structure and evolution of protoplanetary disks (PPDs) are largely governed by disk angular momentum transport, mediated by magnetic fields. In the most observable outer disk, ambipolar diffusion is the primary non-ideal magnetohydrodynamic(MHD) effect. In this work, we study the gas dynamics in outer PPDs by conducting a series of global 3D non-ideal MHD simulations with ambipolar diffusion
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Transit origami: A method to Coherently fold exomoon transits in time series photometry Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-08-02 Kipping D.
AbstractOne of the simplest ways to identify an exoplanetary transit is to phase fold a photometric time series upon a trial period - leading to a coherent stack when using the correct value. Such phase-folded transits have become a standard data visualisation in modern transit discovery papers. There is no analogous folding mechanism for exomoons, which would have to represent some kind of double-fold;
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Moving-mesh radiation-hydrodynamic simulations of wind-reprocessed transients Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-08-02 Calderón D, Pejcha O, Duffell P.
AbstractMotivated by recent theoretical work on tidal disruption events and other peculiar transients, we present moving-mesh radiation-hydrodynamic simulations of radiative luminosity emitted by a central source being reprocessed by a wind-like outflow. We couple the moving-mesh hydrodynamic code JET with our newly-developed radiation module based on mixed-frame grey flux-limited diffusion with implicit
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Circumbinary disc self-gravity governing supermassive black hole binary mergers Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-08-02 Franchini A, Sesana A, Dotti M.
AbstractUnderstanding the interaction of massive black hole binaries with their gaseous environment is crucial since at sub-parsec scales the binary is too wide for gravitational wave emission to take over and to drive the two black holes to merge. We here investigate the interaction between a massive black hole binary and a self-gravitating circumbinary disc using 3D smoothed particle hydrodynamics
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Implications of surface roughness in models of water desorption on the Moon Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-08-02 Davidsson B, Hosseini S.
ABSTRACTThe observed presence of water molecules in the dayside lunar regolith was an unexpected discovery and remains poorly understood. Standard thermophysical models predict temperatures that are too high for adsorbed water to be stable. We propose that this problem can be caused by the assumption of locally flat surfaces that is common in such models. Here, we apply a model that explicitly considers
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Detection of a possible high-confidence radio quasi-periodic oscillation in the BL Lac PKS J2134–0153 Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-29 Ren G, Ding N, Zhang X, et al.
ABSTRACTUsing the Lomb–Scargle periodogram and the weighted wavelet Z-transform techniques, we have searched for quasi-periodic oscillations (QPOs) of the BL Lacertae object (BL Lac), PKS J2134–0153, in the 15-GHz radio light curve announced by the Owens Valley Radio Observatory 40-m telescope during the period from 2008 January 5 to 2019 May 18. This is the first time that the search for periodic
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The BACCO simulation project: a baryonification emulator with neural networks Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-29 Aricò G, Angulo R, Contreras S, et al.
ABSTRACTWe present a neural network emulator for baryonic effects in the non-linear matter power spectrum. We calibrate this emulator using more than 50 000 measurements in a 15D parameter space, varying cosmology and baryonic physics. Baryonic physics is described through a baryonification algorithm, which has been shown to accurately capture the relevant effects on the power spectrum and bispectrum
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GRB jet structure and the jet break Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-20 Lamb G, Kann D, Fernández J, et al.
ABSTRACTWe investigate the shape of the jet break in within-beam gamma-ray burst (GRB) optical afterglows for various lateral jet structure profiles. We consider cases with and without lateral spreading and a range of inclinations within the jet core half-opening angle, θc. We fit model and observed afterglow light curves with a smoothly-broken power-law function with a free-parameter κ that describes
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Magneto-elastic equilibrium of a neutron star crust Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-19 Kojima Y, Kisaka S, Fujisawa K.
ABSTRACTWe examine the equilibrium of a magnetized neutron star crust. We calculate axially symmetric models in which an elastic force balances solenoidal motion driven by a Lorentz force. A large variety of equilibrium models are allowed by incorporating the elastic shear deformation; in addition, toroidal-magnetic-field-dominated models are available. These results remarkably differ from those in
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The frequency by mass of Galactic carbon stars inferred from Gaia measurements of star cluster members Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-19 Pal T, Worthey G.
ABSTRACTWe investigate the frequency of occurrence of Galactic carbon stars as a function of progenitor mass using Gaia data. Small number statistics limit fidelity, but C-star frequency agrees with that observed in the Magellanic Clouds (MCs) down to m ≈ 1.67 M⊙. At m ≈ 1.38 M⊙, the frequency rises by a factor of three even though the frequency appears to drop to zero for the MCs. In fact this is
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Spectroscopic and photometric analysis of symbiotic candidates – I. Ten candidates on classical symbiotic stars Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-16 J Merc, R Gális, M Wolf, P Velez, C Buil, F Sims, T Bohlsen, M Vrašťák, C Boussin, H Boussier, P Cazzato, I Diarrasouba, F Teyssier
Symbiotic stars belong to a group of interacting binaries that display a wide variety of phenomena, including prominent outbursts connected with mass transfer, as well as stellar winds, jets, eclipses, or intrinsic variability of the components. Dozens of new symbiotic stars and candidates have been discovered in recent years. However, there are many objects that are still poorly studied. Some symbiotic
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How many explosions does one need? Quantifying supernovae in globular clusters from iron abundance spreads Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-16 Wirth H, Jerabkova T, Yan Z, et al.
ABSTRACTMany globular clusters (GCs) are known to host multiple populations distinguishable by their light-element content. Less common are GCs displaying iron abundance spreads that are seen as evidence for enrichment through core collapse supernovae (SNe). We present a simple analytical method to estimate the number of SNe required to have occurred in a GC from its metallicity and iron abundance
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Degeneracies between baryons and dark matter: the challenge of constraining the nature of dark matter with JWST Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-16 Khimey D, Bose S, Tacchella S.
ABSTRACTThe James Webb Space Telescope (JWST) will revolutionize our understanding of early galaxy formation, and could potentially set stringent constraints on the nature of dark matter. We use a semi-empirical model of galaxy formation to investigate the extent to which uncertainties in the implementation of baryonic physics may be degenerate with the predictions of two different models of dark matter
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Probabilistic distribution functions Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-16 Jun Yan Lau, James Binney
Observed clusters should be modelled by considering the distribution function (DF) to be a random variable that quantifies the degree of excitation of the system’s normal modes. A system of canonical coordinates for the space of DFs are identified so DFs can be weighted in a consistent way.
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Probing the spectral shape of dust emission with the DustPedia galaxy sample Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-15 Nersesian A, Dobbels W, Xilouris E, et al.
ABSTRACTThe objective of this paper is to understand the variance of the far-infrared (FIR) spectral energy distribution (SED) of the DustPedia galaxies, and its link with the stellar and dust properties. An interesting aspect of the dust emission is the inferred FIR colours which could inform us about the dust content of galaxies, and how it varies with the physical conditions within galaxies. However
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Total mass density slopes of early-type galaxies using Jeans dynamical modelling at redshifts 0.29 < z < 0.55 Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-15 Derkenne C, McDermid R, Poci A, et al.
ABSTRACTThe change of the total mass density slope, γ, of early-type galaxies through cosmic time is a probe of evolutionary pathways. Hydrodynamical cosmological simulations show that at high redshifts density profiles of early-type galaxies were on average steep (γ ∼ −3). As redshift approaches zero, gas-poor mergers progressively cause the total mass density slope to approach the ‘isothermal’ slope
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Convex X-ray spectra of PKS 2155-304 and constraints on the minimum electron energy Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-14 Jagan S, Sahayanathan S, Rieger F, et al.
ABSTRACTThe convex (concave upward) high-energy X-ray spectra of the blazar PKS 2155-304, observed by XMM-Newton, is interpreted as the signature of subdominant inverse-Compton emission. The spectra can be well fitted by a superposition of two power-law contributions which imitate the emission due to synchrotron and inverse-Compton processes. The methodology adopted enables us to constrain the photon
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Impact of astrophysical binary coalescence time-scales on the rate of lensed gravitational wave events Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-13 Mukherjee S, Broadhurst T, Diego J, et al.
ABSTRACTThe expected event rate of lensed gravitational wave sources scales with the merger rate at redshift z ≥ 1, where the optical depth for lensing is high. It is commonly assumed that the merger rate of the astrophysical compact objects is closely connected with the star formation rate, which peaks around redshift z ∼ 2. However, a major source of uncertainty is the delay time between the formation
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Sparse Bayesian mass mapping with uncertainties: hypothesis testing of structure Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-12 M A Price, J D McEwen, X Cai, T D Kitching, C G R Wallis, (for the LSST Dark Energy Science Collaboration)
A crucial aspect of mass mapping, via weak lensing, is quantification of the uncertainty introduced during the reconstruction process. Properly accounting for these errors has been largely ignored to date. We present a new method to reconstruct maximum a posteriori (MAP) convergence maps by formulating an unconstrained Bayesian inference problem with Laplace-type l1-norm sparsity-promoting priors,
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Redshift-space distortions in simulations of the 21-cm signal from the cosmic dawn Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-09 Ross H, Giri S, Mellema G, et al.
ABSTRACTThe 21-cm signal from the Cosmic Dawn (CD) is likely to contain large fluctuations, with the most extreme astrophysical models on the verge of being ruled out by observations from radio interferometers. It is therefore vital that we understand not only the astrophysical processes governing this signal, but also other inherent processes impacting the signal itself, and in particular line-of-sight
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The MAVERIC Survey: Simultaneous Chandra and VLA observations of the transitional millisecond pulsar candidate NGC 6652B Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-08 Paduano A, Bahramian A, Miller-Jones J, et al.
ABSTRACTTransitional millisecond pulsars are millisecond pulsars that switch between a rotation-powered millisecond pulsar state and an accretion-powered X-ray binary state, and are thought to be an evolutionary stage between neutron star low-mass X-ray binaries and millisecond pulsars. So far, only three confirmed systems have been identified in addition to a handful of candidates. We present the
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The loudest stellar heartbeat: characterizing the most extreme amplitude heartbeat star system Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-08 Jayasinghe T, Kochanek C, Strader J, et al.
ABSTRACTWe characterize the extreme heartbeat star system MACHO 80.7443.1718 in the Large Magellanic Cloud using Transiting Exoplanet Survey Satellite (TESS) photometry and spectroscopic observations from the Magellan Inamori Kyocera Echelle (MIKE) and SOAR Goodman spectographs. MACHO 80.7443.1718 was first identified as a heartbeat star system in the All-Sky Automated Survey for SuperNovae (ASAS-SN)
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Future radio continuum cosmology clustering surveys Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-08 Asorey J, Parkinson D.
ABSTRACTThe use of continuum emission radio galaxies as cosmological tracers of the large-scale structure will soon move into a new phase. Upcoming surveys from the Australian Square Kilometre Array Pathfinder (ASKAP), MeerKAT, and the Square Kilometre Array project (SKA) will survey the entire available sky down to an $\sim 100\, \mu$Jy flux limit, increasing the number of detected extra-galactic
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The dust attenuation law in z ∼ 6 quasars Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-08 Di Mascia F, Gallerani S, Ferrara A, et al.
ABSTRACTWe investigate the attenuation law in z ∼ 6 quasars by combining cosmological zoom-in hydrodynamical simulations of quasar host galaxies, with multifrequency radiative transfer calculations. We consider several dust models differing in terms of grain-size distributions, dust mass, and chemical composition, and compare the resulting synthetic spectral energy distributions with data from bright
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Can we distinguish astrophysical from primordial black holes via the stochastic gravitational wave background? Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-08 Mukherjee S, Silk J.
ABSTRACTOne of the crucial windows for distinguishing astrophysical black holes from primordial black holes is through the redshift evolution of their respective merger rates. The low redshift population of black holes of astrophysical origin is expected to follow the star formation rate. The corresponding peak in their merger rate peaks at a redshift smaller than that of the star formation rate peak
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Ionospheric effects in VLBI measured with space-ground interferometer RadioAstron Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-07 Popov M, Bartel N, Burgin M, et al.
ABSTRACTWe report on slow phase variations of the response of the space-ground radio interferometer RadioAstron during observations of pulsar B0329+54. The phase variations are due to the ionosphere and clearly distinguishable from effects of interstellar scintillation. Observations were made in a frequency range of 316–332 MHz with the 110-m Green Bank Telescope and the 10-m RadioAstron telescope
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The PAU survey: estimating galaxy photometry with deep learning Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-06 Cabayol L, Eriksen M, Amara A, et al.
ABSTRACTWith the dramatic rise in high-quality galaxy data expected from Euclid and Vera C. Rubin Observatory, there will be increasing demand for fast high-precision methods for measuring galaxy fluxes. These will be essential for inferring the redshifts of the galaxies. In this paper, we introduce Lumos, a deep learning method to measure photometry from galaxy images. Lumos builds on BKGnet, an algorithm
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White dwarf planetary debris dependence on physical structure distributions within asteroid belts Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-06 McDonald C, Veras D.
ABSTRACTWhite dwarfs that exhibit transit signatures of planetary debris and accreted planetary material provide exceptional opportunities to probe the material composition and dynamical structure of planetary systems. Although previous theoretical work investigating the role of minor body disruption around white dwarfs has focused on spherical bodies, Solar system asteroids can be more accurately
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sofia 2 – an automated, parallel H i source finding pipeline for the WALLABY survey Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-05 T Westmeier, S Kitaeff, D Pallot, P Serra, J M van der Hulst, R J Jurek, A Elagali, B-Q For, D Kleiner, B S Koribalski, K Lee-Waddell, J R Mould, T N Reynolds, J Rhee, L Staveley-Smith
We present sofia 2, the fully automated 3D source finding pipeline for the WALLABY extragalactic H i survey with the Australian SKA Pathfinder (ASKAP). sofia 2 is a reimplementation of parts of the original sofia pipeline in the c programming language and makes use of OpenMP for multithreading of the most time-critical algorithms. In addition, we have developed a parallel framework called sofia-X that
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Efficient exploration and calibration of a semi-analytical model of galaxy formation with deep learning Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-02 Edward J Elliott, Carlton M Baugh, Cedric G Lacey
We implement a sample-efficient method for rapid and accurate emulation of semi-analytical galaxy formation models over a wide range of model outputs. We use ensembled deep learning algorithms to produce a fast emulator of an updated version of the galform model from a small number of training examples. We use the emulator to explore the model’s parameter space, and apply sensitivity analysis techniques
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iCOM formation from radical chemistry: a mechanistic study from cryogenic matrix coupled with IR and EPR spectroscopies Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-01 Gutiérrez-Quintanilla A, Layssac Y, Butscher T, et al.
ABSTRACTInterstellar complex organic molecules (iCOMs) have been identified in different interstellar environments including star forming regions as well as cold dense molecular clouds. Laboratory studies show that iCOMs can be formed either in gas phase or in the solid state, on icy grains, from ‘non-energetic’ (atom-addition/abstraction) or energetic (UV-photon, particle bombardments) processes.
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Far-UV Fe emission as proxy of Eddington ratios Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-06-23 Zheng W.
ABSTRACTThe Eddington ratio is a key parameter that governs the diversity of quasar properties. It can be scaled with a strong anticorrelation between optical Fe iiopt and [O iii] emission. In search of such indicators in the far-UV band, the Hubble Space Telescope far-UV spectra of 150 low-redshift quasars are analysed in combination with their optical SDSS counterparts. The strength of Fe ii+Fe iii
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A computational method for rotating, multilayer spheroids with internal jumps Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-06-14 B Basillais, J-M Huré
We discuss the structure of differentially rotating, multilayer spheroids containing mass–density jumps and rotational discontinuities at the interfaces. The study is based upon a scale-free, numerical method. Polytropic equations of state and cylindrical rotation profiles are assumed. The Bernoulli equation and the Poisson equation for the gravitational potential are solved for each layer separately
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The origin of the dust extinction curve in milky way-like galaxies Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-31 Qi Li, Desika Narayanan, Paul Torrey, Romeel Davé, Mark Vogelsberger
We develop a cosmological model for the evolution of dust grains in galaxies with a distribution of sizes in order to understand the origin of the Milky Way dust extinction curve. Our model considers the formation of active dust in evolved stars, growth by accretion and coagulation, and destruction processes via shattering, sputtering, and astration in the ISM of galaxies over cosmic time. Our main
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Estimating Teff, radius and luminosity of M-dwarfs using high resolution optical and NIR spectral features Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-31 Dhrimadri Khata, Soumen Mondal, Ramkrishna Das, Tapas Baug
We estimate effective temperature (Teff), stellar radius, and luminosity for a sample of 271 M-dwarf stars (M0V-M7V) observed as a part of CARMENES (Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Echelle Spectrographs) radial-velocity planet survey. For the first time, using the simultaneously observed high resolution (R∼90000) spectra in the optical (0
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Asteroseismology of overmassive, undermassive, and potential past members of the open cluster NGC 6791. Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-31 K Brogaard, T Arentoft, J Jessen-Hansen, A Miglio
We perform an asteroseismic investigation of giant stars in the field of NGC 6791 with previous indications of atypical evolution. The analysis makes use of observations from Kepler and Gaia in combination with ground-based photometry, a literature radial-velocity study, and measurements of eclipsing binaries in the cluster. We derive mass, radius, effective temperature, evolutionary stage and apparent
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The central densities of Milky Way-mass galaxies in cold and self-interacting dark matter models Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-31 Omid Sameie, Michael Boylan-Kolchin, Robyn Sanderson, Drona Vargya, Philip F Hopkins, Andrew Wetzel, James Bullock, Andrew Graus, Victor H Robles
We present a suite of baryonic cosmological zoom-in simulations of self-interacting dark matter (SIDM) haloes within the ‘Feedback In Realistic Environment’ (FIRE) project. The three simulated haloes have virial masses of ∼1012 M⊙ at z = 0, and we study velocity-independent self-interaction cross sections of 1 and 10 cm2 g−1. We study star formation rates and the shape of dark matter density profiles
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Hubble diagram at higher redshifts: Model independent calibration of quasars Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-31 Xiaolei Li, Ryan E Keeley, Arman Shafieloo, Xiaogang Zheng, Shuo Cao, Marek Biesiada, Zong-Hong Zhu
In this paper, we present a model-independent approach to calibrate the largest quasar sample. Calibrating quasar samples is essentially constraining the parameters of the linear relation between the log of the ultraviolet (UV) and X-ray luminosities. This calibration allows quasars to be used as standardized candles. There is a strong correlation between the parameters characterizing the quasar luminosity
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The B-type binaries characterisation programme I. Orbital solutions for the 30 Doradus population Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-31 J I Villaseñor, W D Taylor, C J Evans, O H Ramírez-Agudelo, H Sana, L A Almeida, S E de Mink, P L Dufton, N Langer
We present results from the B-type Binaries Characterisation (BBC) programme, a multi-epoch spectroscopic study of 88 early B-type binary candidates in the 30 Doradus region of the Large Magellanic Cloud (LMC). From radial-velocity analysis of 29 observational epochs we confirm the binary status of 64 of our targets, comprising 50 SB1 and 14 SB2 B-type binaries. A further 20 systems (classified as
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Alignment of the magnetic field in star forming regions and why it might be difficult to observe Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-31 Philipp Girichidis
Magnetic fields are an important component of the interstellar medium (ISM) and exhibit strongly varying field strengths and a non-trivial correlation with the gas density. Its dynamical impact varies between individual regions of the ISM and correlates with the orientation of the field with respect to the gas structures. Using high-resolution magneto-hydrodynamical simulations of the ISM we explore
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Towards realistic modeling of the astrometric capabilities of MCAO systems: Detecting an intermediate mass black hole with MAVIS Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-31 Stephanie Monty, François Rigaut, Richard McDermid, Holger Baumgardt, Jesse Cranney, Guido Agapito, J Trevor Mendel, Cédric Plantet, Davide Greggio, Peter B Stetson, Giuliana Fiorentino, Dionne Haynes
Accurate astrometry is a key deliverable for the next generation of multi-conjugate adaptive optics (MCAO) systems. The MCAO Visible Imager and Spectrograph (MAVIS) is being designed for the Very Large Telescope Adaptive Optics Facility and must achieve 150 μas astrometric precision (50 μas goal). To test this before going on-sky, we have created MAVISIM, a tool to simulate MAVIS images. MAVISIM accounts
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Constraining mechanism associated with fast radio burst and glitch from SGR J1935 Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-31 Wei-Hua Wang, Heng Xu, Wei-Yang Wang, Shuang Du, Quan Cheng, Xiao-Ping Zheng, Ren-Xin Xu
The discovery of fast radio burst (FRB) 200428 from galactic SGR J1935+2154 makes it possible to measure rotational changes accompanied by FRBs and to test several FRB models which may be simultaneously associated with glitches. Inspired by this idea, we present order of magnitude calculations to the scenarios proposed. FRB models such as global starquakes, crust fractures and collisions between pulsars
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Constraining Properties of GRB Central Engines with X-ray flares Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-31 Shuang-Xi Yi, Wei Xie, Shuai-Bing Ma, Wei-Hua Lei, Mei Du
X-ray flares in gamma-ray bursts (GRBs) are believed to be generated by the late activities of central engine, and thus provide an useful tool to diagnose the properties of central objects. In this paper, we work on a GRB X-ray flare sample whose bulk Lorentz factors are constrained by two different methods and the jet opening angles are determined by the jet breaks in afterglow lightcurves. Considering
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A bottom-heavy initial mass function for the likely-accreted blue-halo stars of the Milky Way Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-31 Na’ama Hallakoun, Dan Maoz
We use Gaia DR2 to measure the initial mass function (IMF) of stars within 250 pc and masses in the range 0.2 < m/M⊙ < 1.0, separated according to kinematics and metallicity, as determined from Gaia transverse velocity, vT, and location on the Hertzsprung-Russell diagram (HRD). The predominant thin-disc population (vT < 40 km s−1) has an IMF similar to traditional (e.g. Kroupa 2001) stellar IMFs, with
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Inferring the concentration of dark matter subhalos perturbing strongly lensed images Mon. Not. R. Astron. Soc. (IF 5.287) Pub Date : 2021-07-31 Quinn Minor, Manoj Kaplinghat, Tony H Chan, Emily Simon
We demonstrate that the perturbations of strongly lensed images by low-mass dark matter subhalos are significantly impacted by the concentration of the perturbing subhalo. For subhalo concentrations expected in ΛCDM, significant constraints on the concentration can be obtained at HST resolution for subhalos with masses larger than about 1010M⊙. Constraints are also possible for lower mass subhalos
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