We explore chemically homogeneous evolution (CHE) as a formation channel for massive merging binary black holes (BBHs). We develop methods to include CHE in a rapid binary population syn- thesis code, Compact Object Mergers: Population Astrophysics and Statistics (COMPAS), which combines realistic models of binary evolution with cosmological models of the star-formation his- tory of the Universe. For

AbstractWe present catalogues of stellar masses, star formation rates, and ancillary stellar population parameters for galaxies spanning 0 < z < 9 from the Deep Extragalactic VIsible Legacy Survey (DEVILS). DEVILS is a deep spectroscopic redshift survey with very high completeness, covering several premier deep fields including COSMOS (D10). Our stellar mass and star formation rate estimates are self-consistently

AbstractThe Main Belt Comet 133P/Elst-Pizarro is one of the targets of the proposed Chinese small body exploration mission. The rotation and gravity of this comet will be modeled at the end of the mission phase. To prepare this mission, we performed a radio science simulation based on the current knowledge of the characteristics of 133P/Elst-Pizarro. Simulated two-way Earth-orbiter and orbiter-lander

Scalar Field Dark Matter (SFDM), comprised of ultralight (≳ 10−22 eV) bosons, is distinguished from massive (≳ GeV), collisionless Cold Dark Matter (CDM) by its novel structure-formation dynamics as Bose-Einstein condensate (BEC) and quantum superfluid with wave-like properties, described by the Gross-Pitaevski and Poisson (GPP) equations. In the free-field (“fuzzy”) limit of SFDM (FDM), structure

Lyman continuum and line emission are thought to be important agents in the reionization of the early universe. Haro 11 is a rare example of a local galaxy in which Lyα and continuum emission have escaped without being absorbed or scattered by ambient gas and dust, potentially as a consequence of feedback from its X-ray sources. We build on our previous Chandra analysis of Haro 11 by analyzing three

Diffuse filaments connect galaxy clusters to form the cosmic web. Detecting these filaments could yield information on the magnetic field strength, cosmic ray population and temperature of intercluster gas, yet, the faint and large-scale nature of these bridges makes direct detections very challenging. Using multiple independent all-sky radio and X-ray maps we stack pairs of luminous red galaxies as

AbstractWe present a seismic study of δ Scuti based on a mode identification from multicoulor photometry. The dominant frequency can be associated only with a radial mode and the second frequency is, most probably, a dipole mode. The other six frequencies have more ambiguous identifications. The photometric mode identification provided also some constraints on the atmospheric metallicity [m/H]≈+0.5

AbstractEM Cyg is an eclipsing dwarf nova with an orbital period above the period gap of cataclysmic variables. Based on the whole outburst of EM Cyg observed by the Transiting Exoplanet Survey Satellite (TESS) from 2019 July 18 to 2019 August 14, the evolution of quasi-periodic oscillations (QPOs) in EM Cyg was investigated. A QPO with a period of about 1000 s was found both during outburst and quiescence

AbstractThe star formation history and the internal dynamics of Milky Way satellite galaxies are often complicated. In the last years, a substantial fraction of the known faint dwarf satellites have been studied. Some of them show embedded stellar substructures, such as star clusters and even globular star clusters. In this work we study Eridanus II, a dwarf spheroidal satellite which hosts a star

We quantify two main pathways through which baryonic physics biases cluster count cosmology. We create mock cluster samples that reproduce the baryon content inferred from X-ray observations. We link clusters to their counterparts in a dark matter-only universe, whose abundances can be predicted robustly, by assuming the dark matter density profile is not significantly affected by baryons. We derive

Next generation telescopes such as the James Webb Space Telescope (JWST) and the Nancy Grace Roman Space Telescope (NGRST) will enable us to study the first billion years of our Universe in unprecedented detail. In this work we use the Astraeus (semi-numerical rAdiative tranSfer coupling of galaxy formaTion and Reionization in N-body dArk mattEr simUlationS) framework, that couples galaxy formation

We explore hierarchical black hole (BH) mergers in nuclear star clusters (NSCs), globular clusters (GCs) and young star clusters (YSCs), accounting for both original and dynamically assembled binary BHs (BBHs). We find that the median mass of both first- and nth-generation dynamical mergers is larger in GCs and YSCs with respect to NSCs, because the lighter BHs are ejected by supernova kicks from the

AbstractWe present measurements of the morphology of star-forming gas in galaxies from the EAGLE simulations, and its alignment relative to stars and dark matter (DM). Imaging of such gas in the radio continuum enables weak lensing experiments that complement traditional optical approaches. Star-forming gas is typically more flattened than the stars and DM within halo centres, particularly for present-day

AbstractSynchrotron radiation from a decelerating blastwave is a widely accepted model of radio to X-ray afterglow emission from gamma-ray bursts (GRBs). GeV gamma-ray emission detected by the Fermi Large Area Telescope (LAT) and the duration of which extends beyond the prompt gamma-ray emission phase, is also compatible with broad features of afterglow emission. We revisit the synchrotron self-Compton

We present torus modelling for the X-ray spectra of a nearby narrow-line Seyfert 1 galaxy Mrk 1239 (z = 0.0199), based on archival Suzaku, NuSTAR and Swift observations. Our model suggests very soft intrinsic power-law continuum emission of Γ ≈ 2.57 in 2019 and Γ ≈ 2.98 in 2007. By applying a correction factor to the unabsorbed X-ray luminosity, we find that Mrk 1239 is accreting near or around the

Current-day cosmic ray (CR) propagation studies use static Milky-Way models and fit parametrized source distributions to data. Instead, we use three-dimensional magneto-hydrodynamical (MHD) simulations of isolated galaxies with the moving-mesh code Arepo that self-consistently accounts for hydrodynamic effects of CR protons. In post-processing, we calculate their steady-state spectra, taking into account

Both classical and relativistic weak-field and slow-motion perturbations to planetary orbits can be treated as perturbative corrections to the Keplerian model. In particular, tidal forces and General Relativity (GR) induce small precession rates of the apsidal line. Accurate measurements of these effects in transiting exoplanets could be used to test GR and to gain information about the planetary interiors

We present broadband X-ray spectral-timing analysis of the new Galactic X-ray transient MAXI J1348–630 using five simultaneous AstroSat and NICER observations. Spectral analysis using AstroSat data identify the source to be in the soft state for the first three observations and in a faint and bright hard state for the next two. Quasi-periodic oscillations at ∼0.9 and ∼6.9 Hz, belonging to the type-C

Supernova remnants (SNRs) can be rich sources of information on the parent SN explosion. Thus investigating the transition from the phase of SN to that of SNR can be crucial to link these two phases of evolution. Here we aim to study the early development of SNR in more details, paying the major attention to the transition from the early-expansion stage to the Sedov stage and the role played by magnetic

We present the first results from the X-SHOOTER Lyman-α survey at z = 2 (XLS-z2). XLS-z2 is a deep spectroscopic survey of 35 Lyman-α emitters (LAEs) utilising ≈90 hours of exposure time with VLT/X-SHOOTER and covers rest-frame Lyα to Hα emission with R≈4000. We present the sample selection, the observations and the data reduction. Systemic redshifts are measured from rest-frame optical lines for 33/35

We present LAMOST J0140355+392651 (hereafter J0140), a close (Porb = 3.81 hours) binary containing a bloated, low-mass (M ≈ 0.15 M⊙) proto-white dwarf (WD) and a massive (M ≈ 0.95 M⊙) WD companion. The system’s optical light curve is dominated by large-amplitude ellipsoidal variability but also exhibits additional scatter, likely driven by pulsations. The proto-WD is cooler (Teff = 6800 ± 100 K) and

The most distant Kuiper belt objects exhibit the clustering in their orbits, and this anomalous architecture could be caused by Planet 9 with large eccentricity and high inclination. We then suppose that the orbital clustering of minor planets may be observed somewhere else in the solar system. In this paper, we consider the over 7000 Jupiter Trojans from the Minor Planet Center, and find that they

An accurate line list, called XABC, is computed for nitric oxide which covers its pure rotational, vibrational and rovibronic spectra. A mixture of empirical and theoretical electronic transition dipole moments are used for the final calculation of 14N16O rovibronic A 2Σ+ – X 2Π, B 2Π – X2Π and C 2Π – X 2Π which correspond to the γ, β and δ band systems, respectively, as well as minor improvements

We present a model for the halo-mass correlation function that explicitly incorporates halo exclusion and allows for a redefinition of the halo boundary in a flexible way. We assume that haloes trace mass in a way that can be described using a single scale-independent bias parameter. However, our model exhibits scale dependent biasing due to the impact of halo-exclusion, the use of a “soft” (i.e. not

The recent advent of deep observational surveys of local Milky Way ‘analogues’ and their satellite populations allows us to place the Milky Way in a broader cosmological context and to test models of galaxy formation on small scales. In the present study, we use the ΛCDM-based ARTEMIS suite of cosmological hydrodynamical simulations containing 45 Milky Way analogue host haloes to make comparisons to

We present X-ray and radio observations of what may be the closest type Iax supernova (SN) to date, SN 2014dt (d = 12.3 − 19.3 Mpc), and provide tight constraints on the radio and X-ray emission. We infer a specific radio luminosity |$L_R<(1.0-2.4)\times 10^{25}\, \rm {erg\, s^{-1}\, Hz^{-1}}$| at a frequency of 7.5 GHz and a X-ray luminosity |$L_X<1.4\times 10^{38}\, \rm {erg\, s^{-1}}$| (0.3-10 keV)

In this study, we make use of a meso-scale numerical model to obtain the parameters of atmospheric optical turbulence at the Ali observatory above the Tibetan Plateau, which are essential for ground-based optical observations and some adaptive optics techniques. The characterization of the vertical distributions of atmospheric optical turbulence Cn2 and the main integral parameters such as coherence

We present 56Ni mass estimates for 110 normal Type II supernovae (SNe II), computed here from their luminosity in the radioactive tail. This sample consists of SNe from the literature, with at least three photometric measurements in a single optical band within 95–320 d since explosion. To convert apparent magnitudes to bolometric ones, we compute bolometric corrections (BCs) using 15 SNe in our sample

We present a detailed study of the longitudinal proximity effect using a sample of 85 quasars spanning an emission redshift range of 3.5 ≤ zem ≤ 4.5 and Lyman continuum luminosity (L912) ranging from 1.06 × 1031 to 2.24 × 1032 erg s−1 Hz−1. We use the high-quality spectra of these quasars obtained at a spectral resolution of R ∼ 5100 and S/N ∼ 30 using X-SHOOTER spectrograph mounted on the Very Large

We present a systematic search for γ-ray emission from supernovae (SNe) in the Fermi Large Area Telescope (LAT) Pass 8 data. The sample of targets consists of 55,880 candidates from the Open Supernova Catalog. We searched for γ rays from SNe by means of a variable-size sliding-time-window analysis. Our results confirm the presence of transient γ-ray emission from the sources of non-AGN classes, including

The γ-ray emission of star-forming (SF) galaxies is attributed to hadronic interactions of cosmic ray (CR) protons with the interstellar gas and contributions from CR electrons via bremsstrahlung and inverse Compton (IC) scattering. The relative importance of these processes in different galaxy types is still unclear. We model these processes in three-dimensional magneto-hydrodynamical (MHD) simulations

In this work, we use the astraeus (seminumerical rAdiative tranSfer coupling of galaxy formaTion and Reionization in N-body dArk mattEr simUlationS) framework which couples galaxy formation and reionization in the first billion years. Exploring a number of models for reionization feedback and the escape fraction of ionizing radiation from the galactic environment (fesc), we quantify how the contribution

Models of chemical enrichment and inhomogeneity in high-redshift galaxies are challenging to constrain observationally. In this work, we discuss a novel approach to probe chemical inhomogeneities within long Gamma-Ray Burst (GRB) host galaxies, by comparing the absorption metallicity, Zabs, from the GRB afterglow (which probes the environment along the line of sight) with the emission-line metallicity

Machine learning methods are increasingly helping astronomers identify new radio pulsars. However, they require a large amount of labelled data, which is time consuming to produce and biased. Here we describe a Semi-Supervised Generative Adversarial Network (SGAN) which achieves better classification performance than the standard supervised algorithms using majority unlabelled datasets. We achieved

The atmospheres of synchronously rotating exoplanets are intrinsically three-dimensional, and fast vertical and horizontal winds are expected to mix the atmosphere, driving the chemical composition out of equilibrium. Due to the longer computation times associated with multi-dimensional forward models, horizontal mixing has only been investigated for a few case studies. In this paper, we aim to generalize

6–14 μm Spitzer spectra obtained at 6 epochs between April 2005 and October 2008 are used to determine temporal changes in dust features associated with Sakurai’s Object (V4334 Sgr), a low mass post-AGB star that has been forming dust in an eruptive event since 1996. The obscured carbon-rich photosphere is surrounded by a 40-milliarcsec torus and 32 arcsec PN. An initially rapid mid-infrared flux decrease

We present results of a multi-line study of the filamentary infrared dark cloud G351.78-0.54 in the 1.3 and 0.8 mm wavelength bands. The lines of the three isotopologues of carbon monoxide CO, N2H+, CH3CCH and HNCO were observed. The aim was to study the general structure of the filamentary cloud, its fragmentation and physical parameters with the emphasis on properties of dense clumps in this cloud

The distribution of ionised hydrogen during the epoch of reionization (EoR) has a complex morphology. We propose to measure the three-dimensional topology of ionised regions using the Betti numbers. These quantify the topology using the number of components, tunnels and cavities in any given field. Based on the results for a set of reionization simulations we find that the Betti numbers of the ionisation

AbstractA small fraction of GRBs with available data down to soft X-rays (∼0.5 keV) have been shown to feature a spectral break in the low-energy part (∼1-10 keV) of their prompt emission spectrum. The overall spectral shape is consistent with optically thin synchrotron emission from a population of particles that have cooled on a timescale comparable to the dynamic time to energies that are still

AbstractI propose a new type of common envelope jets supernova (CEJSN) events where instead of a single neutron star (NS; or a black hole; BH) a tight binary system of a NS and a main sequence star enters a common envelope evolution (CEE) with a red supergiant. The NS and the main sequence star of the tight binary system merge inside the red supergiant envelope and enter a CEE of their own. The NS

Surveys in the next decade will deliver large samples of galaxy clusters that transform our understanding of their formation. Cluster astrophysics and cosmology studies will become systematics limited with samples of this magnitude. With known properties, hydrodynamical simulations of clusters provide a vital resource for investigating potential systematics. However, this is only realized if we compare

AbstractWe present a variation of the recently updated Munich semi-analytical galaxy formation model, L-Galaxies, with a new gas stripping method. Extending earlier work, we directly measure the local environmental properties of galaxies to formulate a more accurate treatment of ram-pressure stripping for all galaxies. We fully re-calibrate the modified L-Galaxies model using a Markov Chain Monte Carlo

AbstractWe characterise the conditional distributions of the H i gas-to-stellar mass ratio, ${R_{\rm H\, {\small I}}}\equiv {M_{\rm H\, {\small I}}}/{M_{\ast }}$, given the stellar mass, M*, of local galaxies from M* ∼ 107 to 1012 M⊙ separated into centrals and satellites as well as into late- and early-type galaxies (LTGs and ETGs, respectively). To do so, we use 1) the homogeneous “eXtended GALEX

AbstractWe examine the thermodynamic state and cooling of the low-z Circum-Galactic Medium (CGM) in five FIRE-2 galaxy formation simulations of Milky Way-mass galaxies. We find that the CGM in these simulations is generally multiphase and dynamic, with a wide spectrum of largely nonlinear density perturbations sourced by the accretion of gas from the Inter-Galactic Medium (IGM) and outflows from both

AbstractWe use N-body simulations to study the evolution of cuspy cold dark matter (CDM) haloes in the gravitational potential of a massive host. Tidal mass losses reshape CDM haloes, leaving behind bound remnants whose characteristic densities are set by the mean density of the host at the pericentre of their respective orbit. The evolution to the final bound remnant state is essentially complete

The exotic range of known planetary systems has provoked an equally exotic range of physical explanations for their diverse architectures. However, constraining formation processes requires mapping the observed exoplanet population to that which initially formed in the protoplanetary disc. Numerous results suggest that (internal or external) dynamical perturbation alters the architectures of some exoplanetary

AbstractRecently, ground-based Imaging Atmospheric Cherenkov Telescopes have reported the detection of very-high-energy (VHE) gamma-rays from some gamma-ray bursts (GRBs). One of them, GRB 190829A, was triggered by the Swift satellite, and about 2 × 104 s after the burst onset the VHE gamma-ray emission was detected by H.E.S.S. with ∼5σ significance. This event had unusual features of having much smaller

AbstractWe present a detailed analysis of time variability of two distinct C iv broad absorption line (BAL) components seen in the spectrum of J162122.54+075808.4 (zem= 2.1394) using observations from SDSS, NTT and SALT taken at seven different epochs spanning about 15 years. The blue-BAL component (with an ejection velocity, ve ∼ 37 500 km s−1) is an emerging absorption that shows equivalent width

AbstractThe circular polarization of black hole accretion flows can encode properties of the underlying magnetic field structure. Using general relativistic magnetohydrodynamics (GRMHD) simulations, we study the imprint of magnetic field geometry on circular polarization images potentially observable by the Event Horizon Telescope (EHT). We decompose images into the different mechanisms that generate

AbstractNon-ideal MHD effects have been shown recently as a robust mechanism of averting the magnetic braking “catastrophe” and promoting protostellar disc formation. However, the magnetic diffusivities that determine the efficiency of non-ideal MHD effects are highly sensitive to microphysics. We carry out non-ideal MHD simulations to explore the role of microphysics on disc formation and the interplay

AbstractThe two-dimensional B-spline approach recently developed has been applied to calculations of absorption spectra from the n = 3 manifold states of Li atoms in magnetic fields of white dwarfs. A total of 28 magnetized atomic states of five symmetries, 20±, 2( − 1)±, and 2( − 2)+, for this atomic system are involved in the current calculations. Wavelengths and oscillator strengths are presented

We study the time evolution of molecular clouds across three Milky Way-like isolated disc galaxy simulations at a temporal resolution of 1 Myr, and at a range of spatial resolutions spanning two orders of magnitude in spatial scale from ∼10 pc up to ∼1 kpc. The cloud evolution networks generated at the highest spatial resolution contain a cumulative total of ∼80, 000 separate molecular clouds in different

AbstractThe ensemble of chemical element abundance measurements for stars, along with precision distances and orbit properties, provides high-dimensional data to study the evolution of the Milky Way. With this third data release of the Galactic Archaeology with HERMES (GALAH) survey, we publish 678 423 spectra for 588 571 mostly nearby stars (81.2% of stars are within < 2 kpc), observed with the HERMES

Since the discovery of the spectral peculiarities of their prototype α2 Canum Venaticorum in 1897, the so-called ACV variables, which are comprised of several groups of chemically peculiar stars of the upper main sequence, have been the target of numerous photometric and spectroscopic studies. Especially for the brighter ACV variables, continuous observations over about a century are available, which

AbstractHigh redshift sub-millimetre galaxies (SMGs) are usually assumed to be powered by star-formation. However, it has been clear for some time that >20% of such sources brighter than ≈3mJy host quasars. Here we analyse a complete sample of 12 sub-mm LABOCA/ALMA 870 μm sources in the centre of the William Herschel Deep Field (WHDF) with multi-wavelength data available from the X-ray to the radio

AbstractMultiple molecular lines are useful for studying the physical properties of multiphase star-forming gas in different types of galaxies. We probe the molecular gas throughout the disc of the spiral galaxy NGC 5033, hosting an active galactic nucleus (AGN), using multiple low-J CO lines [12CO(1–0, 2–1, 3–2 and 13CO(1–0, 2–1)] and dense gas tracers [HCN(1–0) and HCO+(1–0)]. Firstly, we determine

AbstractUnderstanding the growth of the supermassive black holes (SMBH) powering luminous quasars, their co-evolution with host galaxies, and impact on the surrounding intergalactic medium (IGM) depends sensitively on the duration of quasar accretion episodes. Unfortunately, this time-scale, known as the quasar lifetime, tQ, is still uncertain by orders of magnitude (tQ ≃ 0.01 Myr − 1 Gyr). However

AbstractWe study the interplay between galaxy evolution and central black-hole (BH) growth using the NewHorizon cosmological simulation. BH growth is slow when the dark-matter halo is below a golden mass of $M_{\rm v}\!\sim \!10^{12}\, \rm M_\odot$, and rapid above it. The early suppression is primarily due to gas removal by supernova (SN) feedback in the shallow potential well, predicting that BHs

AbstractThe scientific exploitation of the Dark Energy Spectroscopic Instrument Bright Galaxy Survey (DESI BGS) data requires the construction of mocks with galaxy population properties closely mimicking those of the actual DESI BGS targets. We create a high fidelity mock galaxy catalogue, including information about galaxies and their host dark matter subhaloes. The mock catalogue uses subhalo abundance

AbstractSelection of extreme objects in the data from large-scale sky surveys is a powerful tool for the detection of new classes of astrophysical objects or rare stages of their evolution. The cross-matching of catalogues and analysis of the colour indices of their objects is a usual approach for this problem which has already provided a lot of interesting results. However, the analysis of objects