bluuebunny/crossref_metadata_2025_split huggingface dataset:
Collisional fragmentation and bulk composition tracking in rebound
Authors: Childs Anna C , Steffen Jason H 
Published: January 2022

ABSTRACT
We present a fragmentation module and a composition tracking code for the N-body code rebound. Our fragmentation code utilizes previous semi-analytical models and follows an implementation method similar to fragmentation for the N-body code mercury. In our N-body simulations with fragmentation, we decrease the collision and planet formation time-scales by inflating the particle radii by an expansion factor f and experiment with various values of f to understand how expansion factors affect the collision history and final planetary system. As the expansion factor increases, so do the rate of mergers which produces planetary systems with more planets and planets at larger orbits. Additionally, we present a composition tracking code which follows the compositional change of homogeneous bodies as a function of mass exchange and use it to study how fragmentation and the use of an expansion factor affects volatile delivery to the inner terrestrial disc. We find that fragmentation enhances radial mixing relative to perfect merging and that on average, as f increases so does the average water mass fraction of the planets. Radial mixing decreases with increasing f as collisions happen early on, before the bodies have time to grow to excited orbits and move away from their original location.
Filling the gap between synchronized and non-synchronized sdBs in short-period sdBV+dM binaries with TESS: TIC 137608661, a new system with a well-defined rotational splitting
Authors: Silvotti Roberto , Németh Péter , Telting John H , Baran Andrzej S , Østensen Roy H , Ostrowski Jakub , Sahoo Sumanta K , Prins Saskia 
Published: January 2022

ABSTRACT
TIC 137608661/TYC 4544-2658-1/FBS 0938+788 is a new sdBV+dM reflection-effect binary discovered by the TESS space mission with an orbital period of 7.21 h. In addition to the orbital frequency and its harmonics, the Fourier transform of TIC 137608661 shows many g-mode pulsation frequencies from the subdwarf B (sdB) star. The amplitude spectrum is particularly simple to interpret as we immediately see several rotational triplets of equally spaced frequencies. The central frequencies of these triplets are equally spaced in period with a mean period spacing of 270.12 s, corresponding to consecutive l = 1 modes. From the mean frequency spacing of 1.25 μHz we derive a rotation period of 4.6 d in the deep layers of the sdB star, significantly longer than the orbital period. Among the handful of sdB+dM binaries for which the sdB rotation was measured through asteroseismology, TIC 137608661 is the non-synchronized system with both the shortest orbital period and the shortest core rotation period. Only NY Vir has a shorter orbital period but it is synchronized. From a spectroscopic follow-up of TIC 137608661 we measure the radial velocities of the sdB star, determine its atmospheric parameters, and estimate the rotation rate at the surface of the star. This measurement allows us to exclude synchronized rotation also in the outer layers and suggests a differential rotation, with the surface rotating faster than the core, as found in few other similar systems. Furthermore, an analysis of the spectral energy distribution of TIC 137608661, together with a comparison between sdB pulsation properties and asteroseismic models, gives us further elements to constrain the system.
Simultaneously constraining cosmology and baryonic physics via deep learning from weak lensing
Authors: Lu Tianhuan , Haiman Zoltán , Zorrilla Matilla José Manuel 
Published: January 2022

ABSTRACT
Ongoing and planned weak lensing (WL) surveys are becoming deep enough to contain information on angular scales down to a few arcmin. To fully extract information from these small scales, we must capture non-Gaussian features in the cosmological WL signal while accurately accounting for baryonic effects. In this work, we account for baryonic physics via a baryonic correction model that modifies the matter distribution in dark matter-only N-body simulations, mimicking the effects of galaxy formation and feedback. We implement this model in a large suite of ray-tracing simulations, spanning a grid of cosmological models in Ωm−σ8 space. We then develop a convolutional neural network (CNN) architecture to learn and constrain cosmological and baryonic parameters simultaneously from the simulated WL convergence maps. We find that in a Hyper-Suprime Cam-like survey, our CNN achieves a 1.7× tighter constraint in Ωm−σ8 space (1σ area) than the power spectrum and 2.1× tighter than the peak counts, showing that the CNN can efficiently extract non-Gaussian cosmological information even while marginalizing over baryonic effects. When we combine our CNN with the power spectrum, the baryonic effects degrade the constraint in Ωm−σ8 space by a factor of 2.4, compared to the much worse degradation by a factor of 4.7 or 3.7 from either method alone.
Why hot Jupiters can be large but not too large
Authors: Hou Qiang , Wei Xing 
Published: January 2022

ABSTRACT
Tidal heating is often used to interpret ‘radius anomaly’ of hot Jupiters (i.e. radii of a large fraction of hot Jupiters are in excess of 1.2 Jupiter radius which cannot be interpreted by the standard theory of planetary evolution). In this paper, we find that tidal heating induces another phenomenon ‘runaway inflation’ (i.e. planet inflation becomes unstable and out of control when tidal heating rate is above its critical value). With sufficiently strong tidal heating, luminosity initially increases with inflation, but across its peak it decreases with inflation such that heating is stronger than cooling and runaway inflation occurs. In this mechanism, the opacity near radiative-convective boundary (RCB) scales approximately as temperature to the fourth power and heat cannot efficiently radiate away from planet interior, which induces runaway inflation (similar to a tight lid on a boiling pot). Based on this mechanism, we find that radii of hot Jupiters cannot exceed 2.2RJ, which is in good agreement with the observations. We also give an upper limit for orbital eccentricity of hot Jupiters. Moreover, by comparison to the observations we infer that tidal heating locates near RCB.
Relic galaxy analogues in TNG50 simulation: the formation pathways of surviving red nuggets in a cosmological simulation
Authors: Flores-Freitas Rodrigo , Chies-Santos Ana L , Furlanetto Cristina , De Rossi María Emilia , Ferreira Leonardo , Zenocratti Lucas J , Alamo-Martínez Karla A 
Published: January 2022

ABSTRACT
Relic galaxies are massive compact quiescent galaxies that formed at high-redshift and remained almost unchanged since then. In this work, we search for analogues to relic galaxies in the TNG50 cosmological simulations to understand relic formation and test the ability of TNG50 to reproduce such rare objects. Using stellar mass, age, radius, quiescence, and stellar assembly criteria, we find five subhaloes in TNG50 that could be potential relic analogues. We compare their properties with other constraints imposed by a sample of 13 observed relic galaxies. We find one analogue in TNG50 that simultaneously satisfies most of the available observational constraints, such as metallicity and morphology. It also shows similarities to the confirmed relic NGC 1277, regarding environment and dark matter fraction. By taking into account a degree of relicness, a second relic analogue may also be considered. However, the central parts of the brightness and density profiles of the analogues are less steep than that of real relic galaxies, possibly due to limited numerical resolution. We identify two formation pathways of relic analogues in TNG50 depending on their environment: they either have their remaining gas stripped during the infall into a cluster at z ≲ 1.2 or consume it before z &gt; 1.5. They are then deprived of significant star formation, leaving their stellar populations almost unaltered during the last 9 Gyr. We also find that the analogue progenitors at z ∼ 4 inhabit more massive haloes than progenitors of quiescent galaxies with similar stellar mass at z ∼ 0.
Nebular-phase spectra of Type Ia supernovae from the Las Cumbres Observatory Global Supernova Project
Authors: Graham M L , Kennedy T D , Kumar S , Amaro R C , Sand D J , Jha S W , Galbany L , Vinko J , Wheeler J C , Hsiao E Y , Bostroem K A , Burke J , Hiramatsu D , Hosseinzadeh G , McCully C , Howell D A , Diamond T , Hoeflich P , Wang X , Li W 
Published: January 2022

ABSTRACT
The observed diversity in Type Ia supernovae (SNe Ia) – the thermonuclear explosions of carbon–oxygen white dwarf stars used as cosmological standard candles – is currently met with a variety of explosion models and progenitor scenarios. To help improve our understanding of whether and how often different models contribute to the occurrence of SNe Ia and their assorted properties, we present a comprehensive analysis of seven nearby SNe Ia. We obtained one to two epochs of optical spectra with Gemini Observatory during the nebular phase (&gt;200 d past peak) for each of these events, all of which had time series of photometry and spectroscopy at early times (the first ∼8 weeks after explosion). We use the combination of early- and late-time observations to assess the predictions of various models for the explosion (e.g. double-detonation, off-centre detonation, stellar collisions), progenitor star (e.g. ejecta mass, metallicity), and binary companion (e.g. another white dwarf or a non-degenerate star). Overall, we find general consistency in our observations with spherically symmetric models for SN Ia explosions, and with scenarios in which the binary companion is another degenerate star. We also present an in-depth analysis of SN 2017fzw, a member of the subgroup of SNe Ia which appear to be transitional between the subluminous ‘91bg-like’ events and normal SNe Ia, and for which nebular-phase spectra are rare.
Constraining tidal quality factor using spin period in eclipsing binaries
Authors: Patel Ruskin , Penev Kaloyan 
Published: January 2022

ABSTRACT
Evolution of binary objects under the influence of tides drastically affects the expected observational properties of the system. With the discovery of a large number of close-in hot Jupiter systems and eclipsing binaries from missions such as Kepler and Transiting Exoplanet Survey Satellite, it has become imperative to understand the extent of tidal influence on their formation and observed properties. In the case of binary systems, an efficient tidal dissipation can lead to either spin-up or spin-down of the stars and/or spin–orbit synchronization, depending upon the exchange of angular momentum between the star and the orbit. We combine the eclipsing binary systems from the Kepler mission with stellar and orbital parameters available in the literature to create a catalogue of 41 eclipsing binaries suitable for analysis of tidal dissipation. Empirically, the efficiency of tidal dissipation is parametrized using a modified tidal quality factor ($Q_{\star }^{\prime }$). We find constraints on $Q_{\star }^{\prime }$ using the observed rotation period of the primary star in the eclipsing binary systems. We calculate detailed evolutions of binary systems under the combined influence of tides, stellar evolution, and loss of stellar angular momentum to magnetic winds, and perform Markov chain Monte Carlo simulations to account for the uncertainties in the observed data. Our analysis shows that $\log _{10}{Q^{\prime }_{\star }}=7.818\pm 0.035$ can reproduce the observed primary star spin in almost all systems in our sample.
UOCS – VII. Blue straggler populations of open cluster NGC 7789 with UVIT/AstroSat
Authors: Vaidya Kaushar , Panthi Anju , Agarwal Manan , Pandey Sindhu , Rao Khushboo K , Jadhav Vikrant , Subramaniam Annapurni 
Published: January 2022

ABSTRACT
NGC 7789 is a ∼1.6 Gyr old, populous open cluster located at ∼2000 pc. We characterize the blue straggler stars (BSS) of this cluster using the Ultraviolet (UV) data from the UVIT/AstroSat. We present spectral energy distributions (SED) of 15 BSS candidates constructed using multiwavelength data ranging from UV to IR wavelengths. In 8 BSS candidates, a single temperature SED is found to be satisfactory. We discover hot companions in 5 BSS candidates. The hot companions with Teff ∼ 11750–15500 K, R ∼ 0.069–0.242 R⊙, and L ∼ 0.25–1.55 L⊙, are most likely extremely low mass (ELM) white dwarfs (WDs) with masses smaller than ∼0.18 M⊙, and thereby confirmed post mass transfer systems. We discuss the implication of this finding in the context of BSS formation mechanisms. Two additional BSS show excess in one or more UV filters, and may have a hot companion, however we are unable to characterize them. We suggest that at least 5 of the 15 BSS candidates (33 per cent) studied in this cluster have formed via the mass-transfer mechanism.
Collisional excitation of isotopologs of H2S by molecular hydrogen: D2S and HDS
Authors: Dagdigian Paul J 
Published: January 2022

ABSTRACT
Rate coefficients for transitions between the lower rotational levels of two isotopologs of hydrogen sulphide, specifically HDS and D2S, induced by collisions with para-H2 and ortho-H2 are presented in this work. The availability of these rate coefficients will allow accurate estimates to be made of the abundance of these species in the interstellar medium to be made from astronomical observations. The rate coefficients were computed in close-coupling calculations using potential energy surfaces (PESs) obtained by transformation of the H2S–H2 PES previously calculated with the explicitly correlated CCSD(T)-F12a coupled-cluster method. Rate coefficients for transitions between rotational levels with energies less than 196 cm−1 and temperatures from 5 to 400 K have been calculated for HDS, ortho-D2S, and para-D2S. The rate coefficients for the H2S–H2, HDS–H2, and D2S–H2 systems are compared
ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions – VIII. A search for hot cores by using C2H5CN, CH3OCHO, and CH3OH lines
Authors: Qin Sheng-Li , Liu Tie , Liu Xunchuan , Goldsmith Paul F , Li Di , Zhang Qizhou , Liu Hong-Li , Wu Yuefang , Bronfman Leonardo , Juvela Mika , Lee Chang Won , Garay Guido , Zhang Yong , He Jinhua , Hsu Shih-Ying , Shen Zhi-Qiang , Lee Jeong-Eun , Wang Ke , Tang Ningyu , Tang Mengyao , Zhang Chao , Yue Yinghua , Xue Qiaowei , Li Shanghuo , Peng Yaping , Dutta Somnath , Ge Jixing , Xu Fengwei , Chen Long-Fei , Baug Tapas , Dewangan Lokesh , Tej Anandmayee 
Published: January 2022

ABSTRACT
Hot cores characterized by rich lines of complex organic molecules are considered as ideal sites for investigating the physical and chemical environments of massive star formation. We present a search for hot cores by using typical nitrogen- and oxygen-bearing complex organic molecules (C2H5CN, CH3OCHO, and CH3OH), based on ALMA Three-millimeter Observations of Massive Star-forming regions (ATOMS). The angular resolutions and line sensitivities of the ALMA observations are better than 2 arcsec and 10 mJy beam−1, respectively. A total of 60 hot cores are identified with 45 being newly detected, in which the complex organic molecules have high gas temperatures (&gt; 100 K) and hot cores have small source sizes (&lt; 0.1 pc). So far, this is the largest sample of hot cores observed with similar angular resolution and spectral coverage. The observations have also shown nitrogen and oxygen differentiation in both line emission and gas distribution in 29 hot cores. Column densities of CH3OH and CH3OCHO increase as rotation temperatures rise. The column density of CH3OCHO correlates tightly with that of CH3OH. The pathways for production of different species are discussed. Based on the spatial position difference between hot cores and ultracompact H ii (UC H ii) regions, we conclude that 24 hot cores are externally heated, while the other hot cores are internally heated. The observations presented here will potentially help establish a hot core template for studying massive star formation and astrochemistry.
Emission-line diagnostics of H ii regions using conditional invertible neural networks
Authors: Kang Da Eun , Pellegrini Eric W , Ardizzone Lynton , Klessen Ralf S , Koethe Ullrich , Glover Simon C O , Ksoll Victor F 
Published: January 2022

ABSTRACT
Young massive stars play an important role in the evolution of the interstellar medium (ISM) and the self-regulation of star formation in giant molecular clouds (GMCs) by injecting energy, momentum, and radiation (stellar feedback) into surrounding environments, disrupting the parental clouds, and regulating further star formation. Information of the stellar feedback inheres in the emission we observe, however inferring the physical properties from photometric and spectroscopic measurements is difficult, because stellar feedback is a highly complex and non-linear process, so that the observational data are highly degenerate. On this account, we introduce a novel method that couples a conditional invertible neural network (cINN) with the WARPFIELD-emission predictor (WARPFIELD-EMP) to estimate the physical properties of star-forming regions from spectral observations. We present a cINN that predicts the posterior distribution of seven physical parameters (cloud mass, star formation efficiency, cloud density, cloud age which means age of the first generation stars, age of the youngest cluster, the number of clusters, and the evolutionary phase of the cloud) from the luminosity of 12 optical emission lines, and test our network with synthetic models that are not used during training. Our network is a powerful and time-efficient tool that can accurately predict each parameter, although degeneracy sometimes remains in the posterior estimates of the number of clusters. We validate the posteriors estimated by the network and confirm that they are consistent with the input observations. We also evaluate the influence of observational uncertainties on the network performance.
Dark matter haloes in interacting dark energy models: formation history, density profile, spin, and shape
Authors: Liu Yun , Liao Shihong , Liu Xiangkun , Zhang Jiajun , An Rui , Fan Zuhui 
Published: January 2022

ABSTRACT
The interacting dark energy (IDE) model, which considers the interaction between dark energy and dark matter, provides a natural mechanism to alleviate the coincidence problem and can also relieve the observational tensions under the ΛCDM model. Previous studies have put constraints on IDE models by observations of cosmic expansion history, cosmic microwave background, and large-scale structures. However, these data are not yet enough to distinguish IDE models from ΛCDM effectively. Because the non-linear structure formation contains rich cosmological information, it can provide additional means to differentiate alternative models. In this paper, based on a set of N-body simulations for IDE models, we investigate the formation histories and properties of dark matter haloes and compare with their ΛCDM counterparts. For the model with dark matter decaying into dark energy and the parameters being the best-fitting values from previous constraints, the structure formation is markedly slowed down, and the haloes have systematically lower mass, looser internal structure, higher spin, and anisotropy. This is inconsistent with the observed structure formation, and thus this model can be safely ruled out from the perspective of non-linear structure formation. Moreover, we find that the ratio of halo concentrations between IDE and ΛCDM counterparts depends sensitively on the interaction parameter and is independent of halo mass. This can act as a powerful probe to constrain IDE models. Our results concretely demonstrate that the interaction of the two dark components can affect the halo formation considerably, and therefore the constraints from non-linear structures are indispensable.
Grids of stellar models with rotation VII: models from 0.8 to 300 M⊙ at supersolar metallicity (Z = 0.020)
Authors: Yusof Norhasliza , Hirschi Raphael , Eggenberger Patrick , Ekström Sylvia , Georgy Cyril , Sibony Yves , Crowther Paul A , Meynet Georges , Kassim Hasan Abu , Harun Wan Aishah Wan , Maeder André , Groh Jose H , Farrell Eoin , Murphy Laura 
Published: January 2022

ABSTRACT
We present a grid of stellar models at supersolar metallicity (Z = 0.020) extending the previous grids of Geneva models at solar and sub-solar metallicities. A metallicity of Z = 0.020 was chosen to match that of the inner Galactic disc. A modest increase of 43 per cent (= 0.02/0.014) in metallicity compared to solar models means that the models evolve similarly to solar models but with slightly larger mass-loss. Mass-loss limits the final total masses of the supersolar models to 35 M⊙ even for stars with initial masses much larger than 100 M⊙. Mass-loss is strong enough in stars above 20 M⊙ for rotating stars (25 M⊙ for non-rotating stars) to remove the entire hydrogen-rich envelope. Our models thus predict SNII below 20 M⊙ for rotating stars (25 M⊙ for non-rotating stars) and SNIb (possibly SNIc) above that. We computed both isochrones and synthetic clusters to compare our supersolar models to the Westerlund 1 (Wd1) massive young cluster. A synthetic cluster combining rotating and non-rotating models with an age spread between log10(age/yr) = 6.7 and 7.0 is able to reproduce qualitatively the observed populations of WR, RSG, and YSG stars in Wd1, in particular their simultaneous presence at $\log _{10}(L/\mathit {\mathrm{ L}}_{\odot })$ = 5–5.5. The quantitative agreement is imperfect and we discuss the likely causes: synthetic cluster parameters, binary interactions, mass-loss and their related uncertainties. In particular, mass-loss in the cool part of the HRD plays a key role.
Catalogues of voids as antihaloes in the local Universe
Authors: Desmond Harry , Hutt Maxwell L , Devriendt Julien , Slyz Adrianne 
Published: January 2022

ABSTRACT
A recently proposed algorithm identifies voids in simulations as the regions associated with haloes when the initial overdensity field is negated. We apply this method to the real Universe by running a suite of constrained simulations of the 2M++ volume with initial conditions inferred by the BORG algorithm, along with the corresponding inverted set. Our 101 inverted and uninverted simulations, spanning the BORG posterior, each identify ∼150 000 ‘voids as antihaloes’ with mass exceeding 4.38 × 1011 M⊙ (100 particles) at z = 0 in a full-sky sphere of radius 155 Mpc h−1 around the Milky Way. We calculate the size function, volume filling fraction, ellipticity, central density, specific angular momentum, clustering, and stacked density profile of the voids, and cross-correlate them with those produced by VIDE on the same simulations. We make our antihalo and VIDE catalogues publicly available.
A genuine Large Magellanic Cloud age gap star cluster
Authors: Piatti Andrés E 
Published: January 2022

ABSTRACT
We confirm the existence of a second Large Magellanic Cloud (LMC) star cluster, KMHK 1592, with an age that falls in the middle of the so-called LMC star cluster age gap, a long period of time (∼4–11 Gyr) where no star cluster had been uncovered, except ESO 121-SC 03. The age (8.0 ± 0.5 Gyr) and the metallicity ([Fe/H] = −1.0 ± 0.2 dex) of KMHK 1592 were derived from the fit of theoretical isochrones to the intrinsic star cluster colour–magnitude diagram sequences, which were unveiled using a robust star-by-star membership probability procedure. Because of the relative low brightness of the star cluster, deep GEMINI GMOS images were used. We discuss the pros and cons of three glimpsed scenarios that could explain the presence of both LMC age gap star clusters in the outskirts of the LMC, namely: in situ star cluster formation, capture from the Small Magellanic Cloud, or accretion of a small dwarf galaxy.