bluuebunny/crossref_metadata_2025_split huggingface dataset:
Warm dark matter constraints from the JWST
Authors: Dayal Pratika , Giri Sambit K 
Published: January 2024

ABSTRACT
Warm dark matter (WDM) particles with masses (∼ kilo electronvolt) offer an attractive solution to the small-scale issues faced by the cold dark matter (CDM) paradigm. The delay of structure formation in WDM models and the associated dearth of low-mass systems at high redshifts makes this an ideal time to revisit WDM constraints in light of the unprecedented datasets from the JWST. Developing a phenomenological model based on the halo mass functions in CDM and WDM models, we calculate high redshift ($z \gtrsim 6$), the stellar mass functions (SMF) and the associated stellar mass density (SMD) and the maximum stellar mass allowed in a given volume. We find that: (i) WDM as light as 1.5 keV is already disfavoured by the low-mass end of the SMF (stellar mass $M_* \sim 10^7\,\rm M_\odot$) although caution must be exerted given the impact of lensing uncertainties; (ii) 1.5 keV WDM models predict SMD values that show a steep decrease from 108.8 to $10^{2}\,\rm M_\odot \rm cMpc^{-3}$ from z ∼ 4 to 17 for $M_* \gtrsim 10^8\,\rm M_\odot$; and (iii) the 1.5 keV WDM model predicts a sharp and earlier cut-off in the maximum stellar masses for a given number density (or volume) as compared to CDM or heavier WDM models. For example, with a number density of $10^{-3}\,\rm {cMpc^{-3}}$, 1.5 (3) KeV WDM models do not predict bound objects at $z \gtrsim 12$ (18). Forthcoming JWST observations of multiple blank fields can therefore be used as a strong probe of WDM at an epoch inaccessible by other means.
Pisces VII/Triangulum III – M33’s second dwarf satellite galaxy
Authors: Collins Michelle L M , Karim Noushin , Martinez-Delgado David , Monelli Matteo , Tollerud Erik J , Donatiello Giuseppe , Navabi Mahdieh , Charles Emily , Boschin Walter 
Published: January 2024

ABSTRACT
Pisces VII/Triangulum III (Pisc VII) was discovered in the DESI Legacy Imaging Survey and was shown to be a Local Group dwarf galaxy with follow-up imaging from the 4-m Telescopio Nazionale Galileo. However, this imaging was unable to reach the horizontal branch of Pisc VII, preventing a precision distance measurement. The distance bound from the red giant branch population placed Pisc VII as either an isolated ultra-faint dwarf galaxy or the second known satellite galaxy of Triangulum (M33). Using deep imaging from Gemini GMOS-N, we have resolved the horizontal branch of Pisc VII, and measure a distance of $D=916^{+65}_{-53}$ kpc, making Pisc VII a likely satellite of M33. We also remeasure its size and luminosity from this deeper data, finding $r_{\rm half}=186^{+58}_{-32}$ pc, MV = −6.0 ± 0.3, and $L=2.2^{+0.7}_{-0.5}\times 10^4\, {\rm L}_\odot$. Given its position in the M33 halo, we argue that Pisc VII could support the theory that M33 is on its first infall to the Andromeda system. We also discuss the presence of blue plume and helium burning stars in the colour–magnitude diagram of Pisc VII that are consistent with ages of ∼1.5 Gyr. If these are truly members of the galaxy, it would transform our understanding of how reionization affects the faintest galaxies. Future deep imaging and dynamics could allow significant insight into both the stellar populations of Pisc VII and the evolution of M33.
Hot Jupiter formation in dense star clusters
Authors: Benkendorff L , Flammini Dotti F , Stock K , Cai Maxwell X , Spurzem R 
Published: January 2024

ABSTRACT
Hot Jupiters (HJ) are defined as Jupiter-mass exoplanets orbiting around their host star with an orbital period &lt; 10 d. It is assumed that HJ do not form in-situ but ex-situ. Recent discoveries show that star clusters contribute to the formation of HJ. We present direct N-body simulations of planetary systems in star clusters and analyse the formation of HJ in them. We combine two direct N-body codes: nbody6++gpu for the dynamics of dense star clusters with 32 000 and 64 000 stellar members and lonelyplanets used to follow 200 identical planetary systems around solar mass stars in those star clusters. We use different sets with three, four, or five planets and with the innermost planet at a semimajor axis of 5 or 1 au and follow them for 100 Myr in our simulations. The results indicate that HJs are generated with high efficiency in dense star clusters if the innermost planet is already close to the host star at a semimajor axis of 1 au. If the innermost planet is initially beyond a semimajor axis of 5 au, the probability of a potential HJ ranges between 1.5 and 4.5 per cent. Very dense stellar neighbourhoods tend to eject planets rather than forming HJs. A correlation between HJ formation and angular momentum deficit is not witnessed. Young HJs (tage &lt; 100 Myr) have only been found, in our simulations, in planetary systems with the innermost planet at a semimajor axis of 1 au.
The 2022–2023 accretion outburst of the young star V1741 Sgr
Authors: Kuhn Michael A , Hillenbrand Lynne A , Connelley Michael S , Rich R Michael , Staels Bart , Carvalho Adolfo S , Lucas Philip W , Fremling Christoffer , Karambelkar Viraj R , Lee Ellen , Ahumada Tomás , Ishida Emille E O , De Kishalay , de Souza Rafael S , Kasliwal Mansi M 
Published: January 2024

ABSTRACT
V1741 Sgr (= SPICY 71482/Gaia22dtk) is a Classical T Tauri star on the outskirts of the Lagoon Nebula. After at least a decade of stability, in mid-2022, the optical source brightened by ∼3 mag over 2 months, remained bright until early 2023, then dimmed erratically over the next 4 months. This event was monitored with optical and infrared spectroscopy and photometry. Spectra from the peak (October 2022) indicate an EX Lup-type (EXor) accretion outburst, with strong emission from H i, He i, and Ca ii lines and CO bands. At this stage, spectroscopic absorption features indicated a temperature of T ∼ 4750 K with low-gravity lines (e.g. Ba ii and Sr ii). By April 2023, with the outburst beginning to dim, strong TiO absorption appeared, indicating a cooler T ∼ 3600 K temperature. However, once the source had returned to its pre-outburst flux in August 2023, the TiO absorption and the CO emission disappeared. When the star went into outburst, the source’s spectral energy distribution became flatter, leading to bluer colours at wavelengths shorter than ∼1.6 $\mu$m and redder colours at longer wavelengths. The brightening requires a continuum emitting area larger than the stellar surface, likely from optically thick circumstellar gas with cooler surface layers producing the absorption features. Additional contributions to the outburst spectrum may include blue excess from hotspots on the stellar surface, emission lines from diffuse gas, and reprocessed emission from the dust disc. Cooling of the circumstellar gas would explain the appearance of TiO, which subsequently disappeared once this gas had faded and the stellar spectrum reemerged.
MUSEQuBES: mapping the distribution of neutral hydrogen around low-redshift galaxies
Authors: Dutta Sayak , Muzahid Sowgat , Schaye Joop , Mishra Sapna , Chen Hsiao-Wen , Johnson Sean , Wisotzki Lutz , Cantalupo Sebastiano 
Published: January 2024

ABSTRACT
We present a detailed study of cool, neutral gas traced by Lyα around 4595 z &lt; 0.5 galaxies using stacks of background quasar spectra. The galaxies are selected from our MUSEQuBES low-z survey along with data from the literature. These galaxies, with a median stellar mass of ${\rm log}_{10}(M_*/\rm {\rm M}_{\odot })$ =10.0, are probed by 184 background quasars giving rise to 5054 quasar-galaxy pairs. The median impact parameter is b = 1.5 pMpc (median b/Rvir = 10.4) with 204 (419) quasar-galaxy pairs probing b/Rvir &lt; 1(2). We find excess absorption out to at least ≈15Rvir transverse distance and ≈±600 $\rm km~s^{-1}$ along the line of sight. We show that the median stacked profile for the full sample, dominated by the pairs with b &gt; Rvir, can be explained by a galaxy-absorber two-point correlation function with r0 = 7.6 pMpc and γ = −1.57. There are strong indications that the inner regions (≲Rvir) of the rest equivalent width profile are better explained by a log-linear (or a Gaussian) relation, whereas the outer regions are well described by a power-law, consistent with galaxy-absorber large-scale clustering. Using a sub-sample of 339 galaxies (442 quasar-galaxy pairs, median b/Rvir = 1.6) with star formation rate measurements, we find that the Lyα absorption is significantly stronger for star-forming galaxies compared to passive galaxies, but only within the virial radius. The Lyα absorption at b ≈ Rvir for a redshift-controlled sample peaks at $M_* \sim 10^9~ {\rm {\rm M}_{\odot }}~ (M_{\rm halo} \sim 10^{11}~ \rm {\rm M}_{\odot })$.
Characterization of K2-167 b and CALM, a new stellar activity mitigation method
Authors: de Beurs Zoë L , Vanderburg Andrew , Thygesen Erica , Rodriguez Joseph E , Dumusque Xavier , Mortier Annelies , Malavolta Luca , Buchhave Lars A , Shallue Christopher J , Zieba Sebastian , Kreidberg Laura , Livingston John H , Haywood R D , Latham David W , López-Morales Mercedes , Silva André M 
Published: January 2024

ABSTRACT
We report precise radial velocity (RV) observations of HD 212657 (= K2-167), a star shown by K2 to host a transiting sub-Neptune-sized planet in a 10 d orbit. Using Transiting Exoplanet Survey Satellite (TESS) photometry, we refined the planet parameters, especially the orbital period. We collected 74 precise RVs with the HARPS-N spectrograph between August 2015 and October 2016. Although this planet was first found to transit in 2015 and validated in 2018, excess RV scatter originally limited mass measurements. Here, we measure a mass by taking advantage of reductions in scatter from updates to the HARPS-N Data Reduction System (2.3.5) and our new activity mitigation method called CCF Activity Linear Model (CALM), which uses activity-induced line shape changes in the spectra without requiring timing information. Using the CALM framework, we performed a joint fit with RVs and transits using exofastv2 and find Mp = $6.3_{-1.4}^{+1.4}$ $\, M_{\hbox{$\oplus $}}$ and Rp = $2.33^{+0.17}_{-0.15}$ $\, R_{\hbox{$\oplus $}}$, which places K2-167 b at the upper edge of the radius valley. We also find hints of a secondary companion at a ∼22 d period, but confirmation requires additional RVs. Although characterizing lower mass planets like K2-167 b is often impeded by stellar variability, these systems especially help probe the formation physics (i.e. photoevaporation, core-powered mass-loss) of the radius valley. In the future, CALM or similar techniques could be widely applied to FGK-type stars, help characterize a population of exoplanets surrounding the radius valley, and further our understanding of their formation.
PLATO on the shoulders of TESS: analysing mono-transit planet candidates in TESS data as a prior knowledge for PLATO observations
Authors: Magliano Christian , Covone Giovanni , Nascimbeni Valerio , Inno Laura , Vines Jose I , Kostov Veselin , Fiscale Stefano , Granata Valentina , Montalto Marco , Pagano Isabella , Piotto Giampaolo , Saggese Vito 
Published: January 2024

ABSTRACT
The Transiting Exoplanet Survey Satellite (TESS) and the upcoming mission PLAnetary Transits and Oscillations of stars (PLATO) represent two space-based missions with complementary objectives in the field of exoplanet science. While TESS aims at detecting and characterizing exoplanets around bright and nearby stars on a relative short-period orbit, PLATO will discover a wide range of exoplanets including rocky planets within the habitable zones of their stars. We analyse mono-transit events in TESS data around stars that will or could be monitored by the PLATO mission, offering a unique opportunity to bridge the knowledge gap between the two missions and gain deeper insights into exoplanet demographics and system architectures. We found 48 TESS mono-transit events around stars contained in the all-sky PLATO Input Catalog; of these, at least four will be imaged on the first long-pointing PLATO field, LOPS2. We uniformly vetted this sample to rule out possible false positive detections thus removing 10 signals from the original sample. We developed an analytic method which allows us to estimate both the orbital period and inclination of a mono-transit planet candidate using only the shape of the transit. We derived the orbital period and inclination estimates for 30 TESS mono-transit planet candidates. Finally, we investigated whether these candidates are amenable targets for a CHaracterising ExOPlanets Satellite observing campaign.
Observational evidence for local vertical constraining of H i by molecular cloud complexes
Authors: Nandakumar Meera , Roy Nirupam , Jog Chanda J , Menten Karl M 
Published: January 2024

ABSTRACT
A massive molecular cloud complex represents local gravitational potential that can constrain the vertical distribution of surrounding stars and gas. This pinching effect results in the local corrugation of the scale height of stars and gas which is in addition to the global corrugation of the mid-plane of the disc. For the first time, we report observational evidence for this pinching on the H i vertical structures in the Galactic region (20° &lt; l &lt; 40°), also called W41–W44 region. The H i vertical distribution is modelled by a double Gaussian profile that physically represents a narrow dense gas distribution confined to the mid-plane embedded in a wider diffuse H i. We find that the estimate of the H i scale height distribution of wider components shows corrugated structures at the locations of molecular complexes, as theoretically predicted in literature. While the narrow component is less affected by the pinching, we found a hint of the disc being disrupted by the active dynamics in the local environment of the complex, for example, supernova explosions. Molecular complexes of mass of several $10^6 \rm M_{\odot } $, associated with the mini-starburst region W43 and the supernova remnant W41 show the strongest evidence for the pinching; here a broad trough, with an average width of ∼400 pc and height ∼300 pc, in the disc thickness of the wider component is prominently visible. Searching for similar effect on the stars as well as in the location of other complexes in the Milky Way and other galaxies will be useful to establish this phenomenon more firmly.
Mixing Sinc kernels to improve interpolations in smoothed particle hydrodynamics without pairing instability
Authors: Cabezón Rubén M , García-Senz Domingo 
Published: January 2024

ABSTRACT
The smoothed particle hydrodynamic technique is strongly based on the proper choice of interpolation functions. This statement is particularly relevant for the study of subsonic fluxes and turbulence, where inherent small errors in the averaging procedures introduce excessive damping on the smallest scales. To mitigate these errors, we can increase both the number of interpolating points and the order of the interpolating kernel function. However, this approach leads to a higher computational burden across all fluid regions. Ideally, the development of a single kernel function capable of effectively accommodating varying numbers of interpolating points in different fluid regions, providing good resolution and minimal errors would be highly desirable. In this work, we revisit and extend the main properties of a family of interpolators called Sinc kernels and compare them with the widely used family of Wendland kernels. We show that a linear combination of low- and high-order Sinc kernels generates good-quality interpolators, which are resistant to pairing instability while maintaining good sampling properties in a wide range of neighbour interpolating points, 60 ≤ nb ≤ 400. We show that a particular case of this linear mix of Sincs produces a well-balanced and robust kernel that improves previous results in the Gresho–Chan vortex experiment even when the number of neighbours is not large, while yielding a good convergence rate. Although such a mixing technique is ideally suited for Sinc kernels owing to their excellent flexibility, it can be easily applied to other interpolating families such as the B-splines and Wendland kernels.
Elastic and inelastic cross-sections for 12C + CO2 and 13C + CO2 scattering at superthermal energies
Authors: Gacesa Marko 
Published: January 2024

ABSTRACT
We report elastic and inelastic cross-sections for fast superthermal 12C(3P) and 13C(3P) atoms scattering on 12CO2. The cross-sections were computed using quantum-mechanical rotationally close-coupling formalism with the electronic interaction described by a newly constructed potential energy surface correlating to the lowest energy asymptote of the complex. State-to-state rotational cross-sections, differential cross-sections, and derived transport properties of interest for energy relaxation are also reported. The computed elastic differential cross-sections are found to be strongly anisotropic, show significant energy dependence, and differ by up to 2 percent between the two isotopes of carbon.
A Gaussian-processes approach to fitting for time-variable spherical solar wind in pulsar timing data
Authors: Niţu Iuliana C , Keith Michael J , Tiburzi Caterina , Brüggen Marcus , Champion David J , Chen Siyuan , Cognard Ismaël , Desvignes Gregory , Dettmar Ralf-Jürgen , Grießmeier Jean-Mathias , Guillemot Lucas , Guo Yanjun , Hoeft Matthias , Hu Huanchen , Jang Jiwoong , Janssen Gemma H , Jawor Jedrzej , Karuppusamy Ramesh , Keane Evan F , Kramer Michael , Künsemöller Jörn , Lackeos Kristen , Liu Kuo , Main Robert A , McKee James W , Porayko Nataliya K , Shaifullah Golam M , Theureau Gilles , Vocks Christian 
Published: January 2024

ABSTRACT
Propagation effects are one of the main sources of noise in high-precision pulsar timing. For pulsars below an ecliptic latitude of 5°, the ionized plasma in the solar wind can introduce dispersive delays of order $100\, \mu \mathrm{s}$ around solar conjunction at an observing frequency of 300 MHz. A common approach to mitigate this assumes a spherical solar wind with a time-constant amplitude. However, this has been shown to be insufficient to describe the solar wind. We present a linear, Gaussian-process piecewise Bayesian approach to fit a spherical solar wind of time-variable amplitude, which has been implemented in the pulsar software run_enterprise. Through simulations, we find that the current EPTA+InPTA data combination is not sensitive to such variations; however, solar wind variations will become important in the near future with the addition of new InPTA data and data collected with the low-frequency LOFAR telescope. We also compare our results for different high-precision timing data sets (EPTA+InPTA, PPTA, and LOFAR) of 3 ms pulsars (J0030+0451, J1022+1001, J2145−0450), and find that the solar-wind amplitudes are generally consistent for any individual pulsar, but they can vary from pulsar to pulsar. Finally, we compare our results with those of an independent method on the same LOFAR data of the three millisecond pulsars. We find that differences between the results of the two methods can be mainly attributed to the modelling of dispersion variations in the interstellar medium, rather than the solar wind modelling.
Magnetic field breakout from white dwarf crystallization dynamos
Authors: Blatman Daniel , Ginzburg Sivan 
Published: January 2024

ABSTRACT
A convective dynamo operating during the crystallization of white dwarfs is one of the promising channels to produce their observed strong magnetic fields. Although the magnitude of the fields generated by crystallization dynamos is uncertain, their timing may serve as an orthogonal test of this channel’s contribution. The carbon–oxygen cores of $M\approx 0.5-1.0\, {\rm M}_{\odot }$ white dwarfs begin to crystallize at an age tcryst ∝ M−5/3, but the magnetic field is initially trapped in the convection zone – deep inside the CO core. Only once a mass of mcryst has crystallized, the convection zone approaches the white dwarf’s helium layer, such that the magnetic diffusion time through the envelope shortens sufficiently for the field to break out to the surface, where it can be observed. This breakout time is longer than tcryst by a few Gyr, scaling as tbreak ∝ tcrystf−1/2, where f ≡ 1 − mcryst/M depends on the white dwarf’s initial C/O profile before crystallization. The first appearance of strong magnetic fields B ≳ 1 MG in volume-limited samples approximately coincides with our numerically computed tbreak(M) – potentially signalling crystallization dynamos as a dominant magnetization channel. However, some observed magnetic white dwarfs are slightly younger, challenging this scenario. The dependence of the breakout process on the white dwarf’s C/O profile implies that magnetism may probe the CO phase diagram, as well as uncertainties during the core helium burning phase in the white dwarf’s progenitor, such as the 12C(α, γ)16O nuclear reaction.
Chemical evolution of local post-starburst galaxies: implications for the mass–metallicity relation
Authors: Leung Ho-Hin , Wild Vivienne , Papathomas Michail , Carnall Adam , Zheng Yirui , Boardman Nicholas , Wang Cara , Johansson Peter H 
Published: January 2024

ABSTRACT
We use the stellar fossil record to constrain the stellar metallicity evolution and star-formation histories of the post-starburst (PSB) regions within 45 local PSB galaxies from the MaNGA survey. The direct measurement of the regions’ stellar metallicity evolution is achieved by a new two-step metallicity model that allows for stellar metallicity to change at the peak of the starburst. We also employ a Gaussian process noise model that accounts for correlated errors introduced by the observational data reduction or inaccuracies in the models. We find that a majority of PSB regions (69 per cent at &gt;1σ significance) increased in stellar metallicity during the recent starburst, with an average increase of 0.8 dex and a standard deviation of 0.4 dex. A much smaller fraction of PSBs are found to have remained constant (22 per cent) or declined in metallicity (9 per cent, average decrease 0.4 dex, standard deviation 0.3 dex). The pre-burst metallicities of the PSB galaxies are in good agreement with the mass–metallicity (MZ) relation of local star-forming galaxies. These results are consistent with hydrodynamic simulations, which suggest that mergers between gas-rich galaxies are the primary formation mechanism of local PSBs, and rapid metal recycling during the starburst outweighs the impact of dilution by any gas inflows. The final mass-weighted metallicities of the PSB galaxies are consistent with the MZ relation of local passive galaxies. Our results suggest that rapid quenching following a merger-driven starburst is entirely consistent with the observed gap between the stellar mass–metallicity relations of local star-forming and passive galaxies.