bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simulating Brown Dwarf Observations for Various Mass Functions, Birthrates, and Low-mass Cutoffs
Authors: Raghu Yadukrishna , Kirkpatrick J. Davy , Marocco Federico , Gelino Christopher R. , Bardalez Gagliuffi Daniella C. , Faherty Jacqueline K. , Schurr Steven D. , Schneider Adam C. , Meisner Aaron M. , Kuchner Marc J. , Brooks Hunter , Grigorian Jake ,   The Backyard Worlds: Planet 9 Collaboration
Published: October 2024

Abstract
After decades of brown dwarf discovery and follow-up, we can now infer the functional form of the mass distribution within 20 pc, which serves as a constraint on star formation theory at the lowest masses. Unlike objects on the main sequence that have a clear luminosity-to-mass correlation, brown dwarfs lack a correlation between an observable parameter (luminosity, spectral type, or color) and mass. A measurement of the brown dwarf mass function must therefore be procured through proxy measurements and theoretical models. We utilize various assumed forms of the mass function, together with a variety of birthrate functions, low-mass cutoffs, and theoretical evolutionary models, to build predicted forms of the effective temperature distribution. We then determine the best fit of the observed effective temperature distribution to these predictions, which in turn reveals the most likely mass function. We find that a simple power law (

dN

/

dM
∝

M

−
α

) with α ≈ 0.5 is optimal. Additionally, we conclude that the low-mass cutoff for star formation is ≲0.005 M
⊙. We corroborate the findings of Burgasser, which state that the birthrate has a far lesser impact than the mass function on the form of the temperature distribution, but we note that our alternate birthrates tend to favor slightly smaller values of α than the constant birthrate. Our code for simulating these distributions is publicly available. As another use case for this code, we present findings on the width and location of the subdwarf temperature gap by simulating distributions of very old (8–10 Gyr) brown dwarfs.
slick: Modeling a Universe of Molecular Line Luminosities in Hydrodynamical Simulations
Authors: Garcia Karolina , Narayanan Desika , Popping Gergö , Anirudh R. , Sutherland Sagan , Kaasinen Melanie 
Published: October 2024

Abstract
We present slick (the Scalable Line Intensity Computation Kit), a software package that calculates realistic CO, [C i], and [C ii] luminosities for clouds and galaxies formed in hydrodynamic simulations. Built on the radiative transfer code despotic, slick computes the thermal, radiative, and statistical equilibrium in concentric zones of model clouds, based on their physical properties and individual environments. We validate our results by applying slick to the high-resolution run of the Simba simulations, testing the derived luminosities against empirical and theoretical/analytic relations. To simulate the line emission from a universe of emitting clouds, we have incorporated random forest machine learning (ML) methods into our approach, allowing us to predict cosmologically evolving properties of CO, [C i], and [C ii] emission from galaxies such as luminosity functions. We tested this model in 100,000 gas particles, and 2500 galaxies, reaching an average accuracy of ∼99.8% for all lines. Finally, we present the first model light cones created with realistic and ML-predicted CO, [C i], and [C ii] luminosities in cosmological hydrodynamical simulations, from z = 0 to z = 10.
The Galaxy Activity, Torus, and Outflow Survey (GATOS). IV. Exploring Ionized Gas Outflows in Central Kiloparsec Regions of GATOS Seyferts
Authors: Zhang Lulu , Packham Chris , Hicks Erin K. S. , Davies Ric I. , Shimizu Taro T. , Alonso-Herrero Almudena , Hermosa Muñoz Laura , García-Bernete Ismael , Pereira-Santaella Miguel , Audibert Anelise , López-Rodríguez Enrique , Bellocchi Enrica , Bunker Andrew J. , Combes Francoise , Díaz-Santos Tanio , Gandhi Poshak , García-Burillo Santiago , García-Lorenzo Begoña , González-Martín Omaira , Imanishi Masatoshi , Labiano Alvaro , Leist Mason T. , Levenson Nancy A. , Ramos Almeida Cristina , Ricci Claudio , Rigopoulou Dimitra , Rosario David J. , Stalevski Marko , Ward Martin J. , Esparza-Arredondo Donaji , Delaney Dan , Fuller Lindsay , Haidar Houda , Hönig Sebastian , Izumi Takuma , Rouan Daniel 
Published: October 2024

Abstract
Utilizing JWST MIRI/Medium Resolution Spectrograph integral field unit observations of the kiloparsec-scale central regions, we showcase the diversity of ionized gas distributions and kinematics in six nearby Seyfert galaxies included in the GATOS survey. Specifically, we present spatially resolved flux distribution and velocity field maps of six ionized emission lines covering a large range of ionization potentials (15.8–97.1 eV). Based on these maps, we showcase the evidence of ionized gas outflows in the six targets, and find some highly disturbed regions in NGC 5728, NGC 5506, and ESO137-G034. We propose active galactic nucleus (AGN)-driven radio jets plausibly play an important role in triggering these highly disturbed regions. With the outflow rates estimated based on [Ne V] emission, we find the six targets tend to have ionized outflow rates converged to a narrower range than the previous finding. These results have an important implication for the outflow properties in AGN of comparable luminosity.
The Effects of Cooling on Boundary Layer Accretion
Authors: Dittmann Alexander J. 
Published: October 2024

Abstract
In many cases accretion proceeds from disks onto planets, stars, white dwarfs, and neutron stars via a boundary layer, a region of intense shear where gas transitions from a near-Keplerian speed to that of the surface. These regions are not susceptible to the common magnetorotational and Kelvin–Helmholtz instabilities, and instead global modes generated by supersonic shear instabilities are a leading candidate to govern transport in these regions. This work investigates the dynamics of these systems under a range of thermodynamic conditions, surveying both disk sound speeds and cooling rates. Very fast and very slow cooling have little effect on wave dynamics: In the fast-cooling limit, waves propagate in an effectively isothermal manner, and in the slow-cooling limit, wave propagation is effectively adiabatic. However, when the cooling timescale is comparable to the wave period, wave damping becomes extreme. In cases with intermediate cooling rates, mass and angular momentum transport can be suppressed by orders of magnitude compared to isothermal and uncooled cases. Cooling in accretion disks leads to a preference for wavenumbers near and below the Mach number of the disk; the corresponding lower frequencies can (in nonisothermal systems) couple to gravity modes within the star, potentially driving low-frequency variability such as dwarf nova and quasi-periodic oscillations in accreting systems.
ODIN: Improved Narrowband Lyα Emitter Selection Techniques for z = 2.4, 3.1, and 4.5
Authors: Firestone Nicole M. , Gawiser Eric , Ramakrishnan Vandana , Lee Kyoung-Soo , Valdes Francisco , Park Changbom , Yang Yujin , Ciardullo Robin , Artale María Celeste , Benda Barbara , Broussard Adam , Eid Lana , Farooq Rameen , Gronwall Caryl , Guaita Lucia , Gwyn Stephen , Hwang Ho Seong , Im Sang Hyeok , Jeong Woong-Seob , Karthikeyan Shreya , Lang Dustin , Moon Byeongha , Padilla Nelson , Sawicki Marcin , Seo Eunsuk , Singh Akriti , Song Hyunmi , Troncoso Iribarren Paulina 
Published: October 2024

Abstract
Lyman-alpha-emitting galaxies (LAEs) are typically young, low-mass, star-forming galaxies with little extinction from interstellar dust. Their low dust attenuation allows their Lyα emission to shine brightly in spectroscopic and photometric observations, providing an observational window into the high-redshift Universe. Narrowband surveys reveal large, uniform samples of LAEs at specific redshifts that probe large-scale structure and the temporal evolution of galaxy properties. The One-hundred-deg2 DECam Imaging in Narrowbands (ODIN) utilizes three custom-made narrowband filters on the Dark Energy Camera (DECam) to discover LAEs at three equally spaced periods in cosmological history. In this paper, we introduce the hybrid-weighted double-broadband continuum estimation technique, which yields improved estimation of Lyα equivalent widths. Using this method, we discover 6032, 5691, and 4066 LAE candidates at z = 2.4, 3.1, and 4.5 in the extended COSMOS field (∼9 deg2). We find that [O ii] emitters are a minimal contaminant in our LAE samples, but that interloping Green Pea–like [O iii] emitters are important for our redshift 4.5 sample. We introduce an innovative method for identifying [O ii] and [O iii] emitters via a combination of narrowband excess and galaxy colors, enabling their study as separate classes of objects. We present scaled median stacked spectral energy distributions for each galaxy sample, revealing the overall success of our selection methods. We also calculate rest-frame Lyα equivalent widths for our LAE samples and find that the EW distributions are best fit by exponential functions with scale lengths of w
0 = 53 ± 1, 65 ± 1, and 59 ± 1 Å, respectively.
Lyα Profile Shape as an Escape-fraction Diagnostic at High Redshift
Authors: Pahl Anthony , Shapley Alice , Steidel Charles C. , Reddy Naveen A. , Chen Yuguang , Rudie Gwen C. 
Published: October 2024

Abstract
While the shape of the Lyα profile is viewed as one of the best tracers of ionizing-photon escape fraction (f
esc) within low-redshift (z ∼ 0.3) surveys of the Lyman continuum, this connection remains untested at high redshift. Here, we combine deep, rest-UV Keck/LRIS spectra of 80 objects from the Keck Lyman Continuum Spectroscopic Survey with rest-optical Keck/MOSFIRE spectroscopy in order to examine potential correlations between Lyα profile shape and the escape of ionizing radiation within z ∼ 3 star-forming galaxies. We measure the velocity separation between double-peaked Lyα emission structure (v
sep), between red-side Lyα emission peaks and systemic (v
Lyα,red), and between red-side emission peaks and low-ionization interstellar absorption lines (v
Lyα−LIS). We find that the IGM-corrected ratio of ionizing to nonionizing flux density is significantly higher in KLCS objects with lower v
Lyα,red. We find no significant trend between measures of ionizing-photon escape and v
Lyα−LIS. We compare our results to measurements of z ∼ 0.3 “Green Peas” from the literature and find that KLCS objects have larger v
sep at fixed v
Lyα,red, larger f
esc at fixed v
Lyα,red, and higher v
Lyα,red overall than z ∼ 0.3 analogs. We conclude that the Lyα profile shapes of our high-redshift sources are fundamentally different, and that measurements of profile shape such as v
Lyα,red map on to f
esc in different ways. We caution against building reionization-era f
esc diagnostics based purely on Lyα profiles of low-redshift dwarf galaxies. Tracing v
sep, v
Lyα,red, and f
esc in a larger sample of z ∼ 3 galaxies will reveal how these variables may be connected for galaxies at the epoch of reionization.
Formation of GW230529 from Isolated Binary Evolution
Authors: Zhu Jin-Ping , Hu Rui-Chong , Kang Yacheng , Zhang Bing , Tong Hui , Shao Lijing , Qin Ying 
Published: October 2024

Abstract
In this paper, we explore the formation of the mass-gap black hole-neutron star (mgBHNS) merger detected in gravitational wave (GW) event, i.e., GW230529, from the isolated binary evolution channel, and study potential signatures of its electromagnetic counterparts. By adopting the “delayed” supernova prescription and reasonable model realizations, our population synthesis simulation results can simultaneously match the rate densities of mgBHNS and total BHNS mergers inferred from the population analyses, along with the population distribution of the BH mass in BHNS mergers reported by the LIGO–Virgo–KAGRA Collaboration. Because GW230529 contributes significantly to the inferred mgBHNS rate densities, we suggest that GW230529 can be explained through the isolated binary evolution channel. Considering the AP4 (DD2) equation of state, the probability that GW230529 can make tidal disruption is 12.8% (63.2%). If GW230529 is a disrupted event, its kilonova peak apparent magnitude is predicted ∼23–24 mag, and hence, can be detected by the present survey projects and Large Synoptic Survey Telescope. Since GW230529 could be an off-axis event inferred from the GW observation, its associated gamma-ray burst (GRB) might be too dim to be observed by γ-ray detectors, interpreting the lack of GRB observations. Our study suggests the existence of mgBHNS mergers formed through the isolated binary evolution channel due to the discovery of GW230529, indicating that BHNS mergers are still likely to be multimessenger sources that emit GWs, GRBs, and kilonovae. Although mgBHNS mergers account for ∼50% of the cosmological BHNS population, we find that ≳90% of disrupted BHNS mergers are expected to originate from mgBHNS mergers.
The Effects of Turbulence on Heliosheath Ions and Implications for Energetic Neutral Atoms
Authors: Du Senbei , Opher Merav , Giacalone Joe , Guo Fan , Richardson John D. , Zieger Bertalan 
Published: October 2024

Abstract
The distribution of ions in the heliosheath—the region between the heliospheric termination shock and the heliopause—is important for understanding remote observations of energetic neutral atoms (ENAs). The ion distributions were estimated previously based on hybrid simulations of the heating and evolution of solar wind and interstellar pickup ions across the solar wind termination shock, but these estimates only provide the distributions near the shock. In this work, we use self-consistent hybrid kinetic simulations to investigate the effects of turbulence on ion distributions in the heliosheath. The simulations are compared against Voyager observations, constraining the feasible amplitude and compressibility of turbulence. We find that the heating due to turbulent dissipation can lead to a significant increase in the temperature of thermal solar wind ions. Both turbulent velocity fluctuations and the heating of solar wind ions increase the charge-exchange source for ENAs at low energies (around 100 eV), where current ENA models underpredict observations by more than an order of magnitude. However, the effects of turbulence are likely not strong enough to fully explain these discrepancies.
Shock-induced Partial Alignment in Geometrically Thick Tilted Accretion Disks Around Black Holes
Authors: Gupta Sajal , Dexter Jason 
Published: October 2024

Abstract
We carry out idealized three-dimensional general-relativistic magnetohydrodynamic simulations of prograde, weakly magnetized, and geometrically thick accretion flows where the gas distribution is misaligned from the black hole (BH) spin axis. We evolve the disk for three BH spins: a = 0.5, 0.75, and 0.9375, and we contrast them with a standard aligned disk simulation with a = 0.9375. The tilted disks achieve a warped and twisted steady-state structure, with the outer disk misaligning further away from the BH and surpassing the initial 24° misalignment. However, closer to the BH, there is evidence of partial alignment, as the inclination angle decreases with radius in this regime. Standing shocks also emerged in proximity to the BH, roughly at ∼6 gravitational radii. We show that these shocks act to partially align the inner disk with the BH spin. The rate of alignment increases with increasing BH spin magnitude, but in all cases is insufficient to fully align the gas before it accretes. Additionally, we present a toy model of orbit crowding that can predict the location of the shocks in moderate-to-fast rotating BHs, illustrating a potential physical origin for the behavior seen in simulations—with possible applications in determining the positions of shocks in real misaligned astrophysical systems.
A Close Pair of Orbiters Embedded in a Gaseous Disk: The Repulsive Effect
Authors: Sánchez-Salcedo F. J. , Masset F. S. , Cornejo S. 
Published: October 2024

Abstract
We develop a theoretical framework and use 2D hydrodynamical simulations to study the repulsive effect between two close orbiters embedded in an accretion disk. We consider orbiters on fixed Keplerian orbits with masses low enough to open shallow gaps. The simulations indicate that the repulsion is larger for more massive orbiters and decreases with the orbital separation and the disk’s viscosity. We use two different assumptions to derive theoretical scaling relations for the repulsion. A first scenario assumes that each orbiter absorbs the angular momentum deposited in its horseshoe region by the companion’s wake. A second scenario assumes that the corotation torques of the orbiters are modified because the companion changes the underlying radial gradient of the disk surface density. We find a substantial difference between the predictions of these two scenarios. The first one fails to reproduce the scaling of the repulsion with the disk viscosity and generally overestimates the strength of the repulsion. The second scenario, however, gives results that are broadly consistent with those obtained in the simulations.
Anatomy of the Star Formation in a Tidally Disturbed Disk Galaxy: NGC 3718
Authors: Watts Chandan , Das Mousumi , Barway Sudhanshu 
Published: October 2024

Abstract
We present a UV, optical, and near-IR study of the star-forming complexes in the nearby peculiar galaxy NGC 3718, using Ultraviolet Imaging telescope, Galaxy Evolution Explorer, Spitzer, and DECam Legacy Survey imaging data. The galaxy has a disturbed optical morphology owing to the multiple tidal arms, the warped disk, and the prominent curved dust lanes, but in the near-IR it appears to be a bulge-dominated galaxy. Its disturbed morphology makes it an excellent case to study star formation in a tidally disturbed galaxy that may have undergone a recent minor merger. To study the distribution and properties of the star-forming clumps (SFCs), we divided the galaxy within the R
25 (B band) radius into three parts—the upper, central, and lower regions. Using the UV band images, we investigated the warped star-forming disk, the extended tidal arms, and the distribution and sizes of the 182 SFCs. Their distribution is 49, 60, and 73 in the galaxy’s upper, central, and lower regions, respectively. We determined the UV color, star formation rates (SFRs), star formation density (ΣSFR), and ages of the SFCs. The central disk of the galaxy has a larger mean ΣSFR that is ∼3.3 and ∼1.6 times higher than the upper and lower regions, respectively. We also find that the SFCs in the central disk are older than those in the tidal arms. Our study thus shows that minor mergers can trigger the inside-out growth of galaxy disks, where the younger SFCs are in outer tidal arms and not in the inner disk.
Core Formation by Binary Scouring and Gravitational Wave Recoil in Massive Elliptical Galaxies
Authors: Khonji Nader , Gualandris Alessia , Read Justin I. , Dehnen Walter 
Published: October 2024

Abstract
Scouring by supermassive black hole (SMBH) binaries is the most accepted mechanism for the formation of the cores seen in giant elliptical galaxies. However, an additional mechanism is required to explain the largest observed cores. Gravitational-wave (GW) recoil is expected to trigger further growth of the core, as subsequent heating from dynamical friction of the merged SMBH removes stars from the central regions. We model core formation in massive elliptical galaxies from both binary scouring and heating by GW recoil and examine their unique signatures. We aim to determine whether the nature of cores in 3D space density can be attributed uniquely to either process and whether the magnitude of the kick can be inferred. We perform N-body simulations of galactic mergers of multicomponent galaxies, based on the observed parameters of four massive elliptical galaxies with cores >0.5 kpc. After binary scouring and hardening, the merged SMBH remnant is given a range of GW recoil kicks with 0.5–0.9 of the escape speed of the galaxy. We find that binary scouring alone can form the cores of NGC 1600 and A2147-BCG, which are <1.3 kpc in size. However, the >2 kpc cores in NGC 6166 and A2261-BCG require heating from GW recoil kicks of <0.5 of the galaxy escape speed. A unique feature of GW recoil heating is flatter cores in surface brightness, corresponding to truly flat cores in 3D space density. It also preferentially removes stars on low angular momentum orbits from the galactic nucleus.
A VLA Study of Newly Discovered Southern Latitude Nonthermal Filaments in the Galactic Center: Polarimetric and Magnetic Field Properties
Authors: Paré Dylan M. , Lang Cornelia C. , Morris Mark R. 
Published: October 2024

Abstract
A population of structures unique to the Galactic Center (GC), known as the nonthermal filaments (NTFs), has been studied for over 40 yr, but much remains unknown about them. In particular, there is no widely accepted and unified understanding for how the relativistic electrons illuminating these structures are generated. One possibility is that there are compact and extended sources of cosmic rays, which then diffuse along magnetic flux tubes leading to the illumination of the NTFs through synchrotron emission. In this work, we present and discuss the polarimetric distributions associated with a set of faint NTFs in the GC that have only been studied in total intensity previously. We compare the derived polarized intensity, rotation measure, and intrinsic magnetic field distributions for these structures with the results obtained for previously observed GC NTFs. The results are then used to enhance our understanding of the large-scale polarimetric properties of the GC. We then use the derived polarimetric distributions to constrain models for the mechanisms generating the relativistic electrons that illuminate these structures.
The Clearing Timescale for Infrared-selected Star Clusters in M83 with HST
Authors: Deshmukh Suyash , Linden Sean T. , Calzetti Daniela , Adamo Angela , Messa Matteo , Grasha Kathryn , Sabbi Elena , Smith Linda , Johnson Kelsey E. 
Published: October 2024

Abstract
We present an analysis of Hubble Space Telescope data from Wide Field Camera 3 (WFC3)/Ultraviolet Imaging Spectrometer, WFC3/IR, and the Advanced Camera for Surveys, investigating the young stellar cluster (YSC) population in the face-on spiral galaxy M83. Within the field of view of the IR pointings, we identify 454 sources with compact F814W continuum and Paβ line emission with a S/N ≥ 3 as possible YSC candidates embedded in dust. We refine this selection to 97 candidates based on their spectral energy distributions, multiwavelength morphology, and photometric uncertainties. For sources that are detected in all bands and have mass >102.8
M
⊙ (53 sources), we find that by 2 Myr 75% of IR-selected star clusters have an A

V
≤ 1 and that by 3 Myr the fraction rises to ∼82%. This evidence of early clearing implies that presupernova (pre-SN) feedback from massive stars is responsible for clearing the majority of the natal gas and dust that surround IR-selected star clusters in M83. Further, this result is consistent with previous estimates based on WFC3 observations and adds to the growing body of literature suggesting pre-SN feedback to be crucial for YSC emergence in normal star-forming galaxies. Finally, we find a weak correlation between the YSC concentration index and age over the first 10 Myr, which matches previous studies and indicates little or no change in the size of YSCs in M83 during their early evolution.