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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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;

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

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

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

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

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

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

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

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

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

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

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

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.

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

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

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

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

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,

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

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

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)

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

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

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

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

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

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

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

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

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.

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

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

City service demand fluctuates across space and time. Although various data, such as 311 hotline data and social media data, have been used to explore the spatiotemporal patterns of city services, data uncertainty and the uneven distribution of service demand are overlooked to some extent and thus could result in bias. To overcome these shortcomings, top-down collected city service data that fully

Abstract Comparison of chlorophyll data of three sets of CMIP5 models for RCP 4.5 (MPI-ESM-MR, HadGEM2-ES and GFDL-ESM2M) and RCP 6.0 (IPSL-CM5A-LR, HadGEM2-ES and GFDL-ESM2M) were done with satellite derived data (OC-CCI) for the period of 1998–2017 along four Indian coastal regions. The monthly, yearly and zone-wise seasonal comparison between model and satellite data were carried out. Analysis of

The western Indian volcanic rifted margin, and its large-scale tectonic feature called the Panvel flexure, formed at 62.5 Ma during the late stages of Deccan Traps flood volcanism. We present a geological account of late-stage (≤ 62.5 Ma) Deccan volcanism and plutonism in the relatively poorly studied Thane–Vasai region in the Panvel flexure zone. The study area shows west-dipping basaltic sequences

We present here the paleointensity results of basalt samples from Rajmahal (25.10°N; 87.40°E) and Sylhet Traps (25.22°N; 91.71°E) of eastern India (~117 Ma) to know the strength of the earth's magnetic field during the early Cretaceous from these locations. The modified version of the Thellier–Thellier paleointensity method of, in field-zero field-zero field-in field (IZZI) protocol and systematic

The linear and weakly nonlinear dust-ion-acoustic wave propagation obliquely to an external magnetic field is studied in a magnetized dusty plasma which consists of magnetized fluid ions bearing with anisotropic pressure, suprathermal electrons, and static dust grains. In the linear regime, the magnetized dusty plasma supports the propagation of the fast electrostatic dust-ion-cyclotron (EDIC) and

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

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

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

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

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

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

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