bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mapping the Dense Molecular Gas toward 13 Supernova Remnants
Authors: Tu 涂 Tian-Yu 天宇 , Chen 陈 Yang 阳 , Liu 刘 Qian-Cheng 前程 
Published: December 2024

Abstract
Supernova remnants (SNRs) can exert strong influence on molecular clouds (MCs) through interaction by shock wave and cosmic rays. In this paper, we present our mapping observation of HCO+ and

HCN

1–0 lines toward 13 SNRs interacting with MCs, together with archival data of CO isotopes. Strong HCO+ emission is found in the fields of view of SNRs W30, G9.7−0.0, Kes 69, 3C 391, 3C 396, W51C, HC 40, and CTB109 in the local-standard-of-rest velocity intervals in which they are suggested to show evidence of SNR–MC interaction. We find an incomplete 12CO shell surrounding G9.7−0.0 with an expanding motion. This shell may be driven by the stellar wind of the SNR progenitor. We also find an arc of 12CO gas spatially coincident with the northwestern radio shell of Kes 69. As for the HCO+ line emission, SNRs 3C 391 and W51C exhibit significant line profile broadening indicative of shock perturbation, and CTB109 exhibits a possible blueshifted line wing brought by shock interaction. We do not find significant variation of the

I
(

HCO
+

)
/
I
(
HCN
)

line ratio between broad-line and narrow-line regions, among different SNRs, and between MCs associated with SNRs and typical Galactic MCs. Therefore, we caution on using the

I
(

HCO
+

)
/
I
(
HCN
)

line ratio as a diagnostic of SNR feedback and cosmic-ray (CR) ionization. We also estimate the N(HCO+)/N(CO) abundance ratio in 11 regions toward the observed SNRs, but they show little difference from the typical values in quiescent MCs, possibly because N(HCO+)/N(CO) is not an effective tracer of CR ionization.
Pulse-profile Modeling and Spin–Orbit Alignment in a Suzaku Sample of Accreting X-Ray Binary Pulsars
Authors: Laycock Silas G. T. , Cappallo Rigel C. , Pradhan Pragati , Christodoulou Dimitris M. , Paul Biswajit 
Published: December 2024

Abstract
We report pulse-profile modeling of a sample of 23 X-ray binary pulsars observed with the Suzaku X-ray satellite. These pulsars have spin periods ranging from 0.7 to 9400 s, and their X-ray emission is powered by the accretion from their stellar companions. We fitted each individual pulse profile with the Polestar geometric model, which accounts for X-ray emission from two hot spots modeled as a simple combination of fan+pencil beam components, including an approximation for gravitational light bending. In 14 of 21 cases, our measurements of the inclinations of the pulsar spin axes broadly agree with the corresponding inclinations of the orbital planes of the binary systems determined by various other means, a striking outcome with a mere 6 × 10−7 probability of occurring by chance. The implications of our study are as follows: (a) apparently, accretion torques have had time to erase spin–orbit misalignment caused by supernova kicks in two-thirds of the systems; (b) many X-ray binary pulsars have dominant dipolar surface magnetic fields, in contrast to the recently reported exotic configurations in millisecond pulsars; and (c) if the binary inclinations can be determined by pulse-profile modeling, even for a subset of the ∼200 known X-ray binary pulsars, most of which orbital inclinations are as yet poorly constrained, it raises the prospect of tightening dramatically ongoing neutron-star mass determinations. This is because masses in binary systems overwhelmingly come from an orbital-mechanics formulation (Kepler’s third law), in which the dominant source of uncertainty is the inclination of the orbital plane.
LMC Calls, Milky Way Halo Answers: Disentangling the Effects of the MW–LMC Interaction on Stellar Stream Populations
Authors: Brooks Richard A. N. , Garavito-Camargo Nicolás , Johnston Kathryn V. , Price-Whelan Adrian M. , Sanders Jason L. , Lilleengen Sophia 
Published: December 2024

Abstract
The infall of the LMC into the Milky Way (MW) has dynamical implications throughout the MW’s dark matter halo. We study the impact of this merger on the statistical properties of populations of simulated stellar streams. Specifically, we investigate the radial and on-sky angular dependence of stream perturbations caused by the direct effect of stream–LMC interactions and/or the response of the MW dark matter halo. We use a time-evolving MW–LMC simulation described by basis function expansions to simulate streams. We quantify the degree of perturbation using a set of stream property statistics including the misalignment of proper motions with the stream track. In the outer halo, direct stream–LMC interactions produce a statistically significant effect, boosting the fraction of misaligned proper motions by ∼25% relative to the model with no LMC. Moreover, there is on-sky angular dependence of stream perturbations: the highest fractions of perturbed streams coincide with the same on-sky quadrant as the present-day LMC location. In the inner halo, the MW halo dipole response primarily drives stream perturbations, but it remains uncertain whether this is a detectable signature distinct from the LMC’s influence. For the fiducial MW–LMC model, we find agreement between the predicted fraction of streams with significantly misaligned proper motions,

ϑ

¯

>
10
°

, and Dark Energy Survey data. Finally, we predict this fraction for the Rubin Observatory Legacy Survey of Space and Time (LSST) footprint. Using LSST data will improve our constraints on dark matter models and LMC properties, as it is sensitive to both.
Analysis of Gamma-Ray Burst Closure Relationship in Multiple Wavelengths
Authors: Dainotti M. G. , Bhardwaj S. , Bissaldi E. , Fraija N. , Sourav S. , Galvan-Gamez A. 
Published: December 2024

Abstract
Gamma-ray bursts (GRBs) are intense pulses of high-energy emission associated with the death of massive stars or compact objects’ coalescence. Their multiwavelength observations help verify the reliability of the standard fireball model. We analyze 14 GRBs observed contemporaneously in gamma rays by the Fermi Large Area Telescope, in X-rays by the Swift Telescope, and in the optical bands by Swift and many ground-based telescopes. We study the correlation between the spectral and temporal indices using closure relations according to the synchrotron forward-shock model in a stratified medium (n ∝ r
−k
) with k ranging from 0 to 2.5. We find that the model without energy injection is preferred over the one with energy injection in all the investigated wavelengths. In gamma rays, we only explored the ν > max{ν

c
, ν

m
} (slow cooling, SC/fast cooling, FC) cooling condition (where ν

c
and ν

m
are the cooling and characteristic frequencies, namely the frequencies at the spectral break). In the X-ray and optical bands, we explored all the cooling conditions, including ν

m
< ν < ν

c
(SC), ν

c
< ν < ν

m
(FC), and SC/FC, and found a clear preference for SC for X-rays and SC/FC for optical. Within these cooling conditions, X-rays exhibit the highest rate of occurrence for the density profile with k = 0, while the optical band has the highest occurrence for k = 2.5 when considering no energy injection. Although we can pinpoint a definite environment for some GRBs, we find degeneracies in other GRBs.
Multiwavelength Constraints on the Local Black Hole Occupation Fraction
Authors: Burke Colin J. , Natarajan Priyamvada , Baldassare Vivienne F. , Geha Marla 
Published: December 2024

Abstract
The fraction of dwarf galaxies hosting central, intermediate-mass black holes (IMBHs) at low redshifts is an important observational probe of black hole seeding at high redshift. Detections of nuclear accretion signatures in dwarf galaxies provides strong evidence for the presence of these IMBHs. We develop a Bayesian model to infer the black hole occupation fraction assuming a broken power-law Eddington ratio distribution function. Our approach accounts for nondetections, incompleteness, and contamination from star-forming-related emission. We apply this model to galaxies with X-ray data from the Chandra Source Catalog at distances <50 Mpc, radio data from the Very Large Array Sky Survey at <50 Mpc, and optical variability data from the Palomar Transient Factory at z < 0.055. We find a black hole occupation fraction of at least 90% at stellar masses of M
⋆ = 108
M
⊙ and at least 39% at M
⋆ = 107
M
⊙ (95% confidence intervals). We show the resulting black hole mass function. These constraints on the IMBH population have implications for the Laser Interferometer Space Antenna mission and for cosmological models of black hole seeding and growth. We also constrain the extremely low-luminosity end (L
bol ≲ 1040 erg s−1) of the active galactic nucleus (AGN) luminosity functions at z = 0. Our AGN luminosity functions are broadly consistent with an extrapolation of the shallow slope of the AGN luminosity functions from previous work.
Microlensing Events in Five Years of Photometry from the Zwicky Transient Facility
Authors: Zhai Ruocheng , Rodriguez Antonio C. , Mao Shude , Lam Casey Y. , Bellm Eric C. , Purdum Josiah , Masci Frank J. , Wold Avery 
Published: December 2024

Abstract
Microlensing has a unique advantage for detecting dark objects in the Milky Way, such as free-floating planets, neutron stars, and stellar-mass black holes. Most microlensing surveys focus on the Galactic bulge, where higher stellar density leads to a higher event rate. However, microlensing events in the Galactic plane have closer lenses and longer timescales, which leads to a greater chance of measuring microlens parallax, providing an additional constraint on the mass of the lens. This work searches for microlensing events in Zwicky Transient Facility (ZTF) Data Release 17 from 2018 to 2023 in the Galactic plane region. We find 124 high-confidence microlensing events and 54 possible events, all available online (see footnote 11). Thus, with 2 yr of additional ZTF data in DR17, we have more than doubled the number of microlensing events (60) found in the previous 3 yr DR5 search. In the event selection, we use the efficient EventFinder algorithm to detect microlensing signals, which could be used for large data sets such as future ZTF data releases or data from the Rubin Observatory Legacy Survey of Space and Time. Using detection efficiencies of ZTF fields obtained from catalog-level simulations, we calculate the mean Einstein timescale to be 〈t
E〉 = 51.7 ± 3.3 days, smaller than previous results of the Galactic plane but within 1.5σ. We also calculate optical depths and event rates, although some caution is needed due to the use of visual inspection when creating our final sample. Spectroscopy of three possible candidates confirms their microlensing nature.
The Relation between AGN and Host-galaxy Properties in the JWST Era. I. Seyferts at Cosmic Noon are Obscured and Disturbed
Authors: Bonaventura Nina , Lyu 吕 Jianwei 建伟 , Rieke George H. , Alberts Stacey , Willmer Christopher N. A. , Pérez-González Pablo G. , Bunker Andrew J. , Stone Meredith , D’Eugenio Francesco , Williams Christina C. , Maseda Michael V. , Willott Chris J. , Ji Zhiyuan , Baker William M. , Carniani Stefano , Charlot Stephane , Chevallard Jacopo , Curtis-Lake Emma , Eisenstein Daniel J. , Hainline Kevin , Hausen Ryan , Nelson Erica J. , Rieke Marcia J. , Robertson Brant , Shivaei Irene 
Published: December 2024

Abstract
The morphology of a galaxy reflects the mix of physical processes occurring within and around it, offering indirect clues to its formation and evolution. We apply both visual classification and computer vision to test the suspected connection between galaxy mergers and active galactic nucleus (AGN) activity, as evidenced by a close/merging galaxy pair, or tidal features surrounding an apparently singular system. We use JADES JWST/NIRCam imagery of a complete, multiwavelength AGN sample recently expanded with JWST/Mid-Infrared Instrument (MIRI) photometry. This 0.9–25 μm data set enables constraints on the host-galaxy morphologies of a broad range of AGN beyond z ∼ 1, including heavily obscured examples missing from previous studies. Our primary AGN sample consists of 243 lightly to highly obscured X-ray-selected AGN and 138 presumed Compton-thick, mid-infrared-bright/X-ray-faint AGN revealed by MIRI. Utilizing the shape asymmetry morphology indicator, A

S
, as the metric for disturbance, we find that 88% of the Seyferts sampled are strongly spatially disturbed (A

S
> 0.2). The experimental design we employ reveals a ≳3σ obscuration–merger (N
H–A

S
) correlation at 0.6 < z < 2.4, and also recovers a physical distinction between the X-ray- and mid-IR-detected AGN suggestive of their link to a common evolutionary scenario. Placing the observed pattern of disturbances in the context of the other average host-galaxy properties, we conclude that mergers are common among obscured AGN. This finding presents tension with the leading model on AGN fueling that requires Seyfert AGN with subquasar luminosities (L
bol < 1045 erg s−1) to evolve only through nonmerger mechanisms.
Frozen-field Modeling of Coronal Condensations with MPI-AMRVAC. II. Optimization and Application in 3D Models
Authors: Zhou Yuhao , Li Xiaohong , Jenkins Jack M. , Hong Jie , Keppens Rony 
Published: December 2024

Abstract
The frozen-field hydrodynamic (ffHD) model is a simplification of the full magnetohydrodynamical equations under the assumption of a rigid magnetic field, which significantly reduces computational complexity and enhances efficiency. In this work, we combine the ffHD prescription with hyperbolic thermal conduction (TC) and the Transition Region Adaptive Conduction (TRAC) method to achieve further optimization. A series of 2D tests are done to evaluate the performance of the hyperbolic TC and the TRAC method. The results indicate that hyperbolic TC, while showing limiter-affected numerical dissipation, delivers outcomes comparable to classic parabolic TC. The TRAC method effectively compensates for the underestimation of enthalpy flux in low-resolution simulations, as evaluated on tests that demonstrate prominence formation. We present an application of the ffHD model that forms a 3D prominence embedded in a magnetic flux rope, which develops into a stable slab-like filament. The simulation reveals a prominence with an elongated spine and a width consistent with observations, highlighting the potential of the ffHD model in capturing the dynamics of solar prominences. Forward modeling of the simulation data produces synthetic images at various wavelengths, providing insights into the appearance of prominences and filaments in different observational contexts. The ffHD model, with its computational efficiency and the demonstrated capability to simulate complex solar phenomena, offers a valuable tool for solar physicists, and is implemented in the open-source MPI-AMRVAC framework.
NGC 628 in SIGNALS: Explaining the Abundance-ionization Correlation in H ii Regions
Authors: Garner Ray , Kennicutt Robert , Rousseau-Nepton Laurie , Olivier Grace M. , Fernández-Arenas David , Robert Carmelle , Martin René Pierre , Amram Philippe 
Published: December 2024

Abstract
The variations of oxygen abundance and ionization parameter in H ii regions are usually thought to be the dominant factors that produced variations seen in observed emission-line spectra. However, if and how these two quantities are physically related is hotly debated in the literature. Using emission line data of NGC 628 observed with SITELLE as part of the Star formation, Ionized Gas, and Nebular Abundances Legacy Survey (SIGNALS), we use a suite of photoionization models to constrain the abundance and ionization parameters for over 1500 H ii regions throughout its disk. We measure an anticorrelation between these two properties, consistent with expectations, although with considerable scatter. Secondary trends with dust extinction and star formation rate surface density potentially explain the large scatter observed. We raise concerns throughout regarding various modeling assumptions and their impact on the observed correlations presented in the literature.
New Insight of Time-transformed Symplectic Integrator. I. Hybrid Methods for Hierarchical Triples
Authors: Wang 王 Long 龙 
Published: December 2024

Abstract
Accurate N-body simulations of multiple systems such as binaries and triples are essential for understanding the formation and evolution of interacting binaries and binary mergers, including gravitational wave sources, blue stragglers, and X-ray binaries. The logarithmic time-transformed explicit symplectic integrator (LogH), also known as algorithmic regularization, is a state-of-the-art method for this purpose. However, we show that this method is accurate for isolated Kepler orbits because of its ability to trace Keplerian trajectories, but much less accurate for hierarchical triple systems. The method can lead to an unphysical secular evolution of inner eccentricity in Kozal–Lidov triples, despite a small energy error. We demonstrate that hybrid methods, which apply LogH to the inner binary and alternative methods to the outer bodies, are significantly more effective, though not symplectic. Additionally, we introduce a more efficient hybrid method, BlogH, which eliminates the need for time synchronization and is time symmetric. The method is implemented in the few-body code SDAR. We explore suitable criteria for switching between the LogH and BlogH methods for general triple systems. These hybrid methods have the potential to enhance the integration performance of hierarchical triples.
Mining Double-line Spectroscopic Candidates in the LAMOST Medium-resolution Spectroscopic Survey Using a Human–AI Hybrid Method
Authors: Li Shan-shan , Li Chun-qian , Li Chang-hua , Fan Dong-wei , Xu Yun-fei , Mi Lin-ying , Cui Chen-zhou , Shi Jian-rong 
Published: December 2024

Abstract
We utilize a hybrid approach that integrates the traditional cross-correlation function (CCF) and machine learning to detect spectroscopic multiple star systems, specifically focusing on double-line spectroscopic binaries (SB2s). Based on the ninth data release (DR9) of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), which includes a medium-resolution survey (MRS) containing 29,920,588 spectra, we identify 27,164 double-line and 3124 triple-line spectra, corresponding to 7096 SB2 candidates and 1903 triple-line spectroscopic binary (SB3) candidates, respectively, representing about 1% of the selected data set from LAMOST-MRS DR9. Notably, 70.1% of the SB2 candidates and 89.6% of the SB3 candidates are newly identified. Compared to using only the traditional CCF technique, our method significantly improves the efficiency of detecting SB2s, saving time on visual inspections by a factor of 4.
The Blue Horizontal-branch Stars from the LAMOST Survey: Atmospheric Parameters
Authors: Ju Jie , Zhang Bo , Cui Wenyuan , Huo Zhenyan , Liu Chao , Huang Yang , Shi Jianrong 
Published: December 2024

Abstract
Blue horizontal-branch (BHB) stars are crucial for studying the structure of the Galactic halo. Accurate atmospheric parameters of BHB stars are essential for investigating the formation and evolution of the Galaxy. In this work, a data-driven technique named Stellar Label Machine (SLAM) is used to estimate the atmospheric parameters of Large Sky Area Multi-Object Fiber Spectroscopic Telescope low-resolution spectra for BHB stars with a set of A-type theoretical spectra as the training data set. We add color indexes ((BP − G), (G − RP), (BP − RP), (J − H)) during the training process to constrain the stellar temperature further. Finally, we derive the atmospheric parameters (T
eff, log g, [Fe/H]) for 5355 BHB stars. Compared to existing literature results, our results are more robust, and after taking the color index into account the resulting precision of T
eff and log g is significantly improved, especially for the spectrum with a low signal-to-noise ratio (S/N). Based on the duplicate observations with an S/N difference <20%, the random errors are around 30 K, 0.1 dex, and 0.12 dex for T
eff, log g, and [Fe/H], respectively. The stellar labels provided by SLAM are also compared to those from the high-resolution spectra in the literature. The standard deviation between the predicted star labels and the published values from the high-resolution spectra is adopted as the statistical uncertainty of our results. They are σ(T
eff) = 76 K, σ(log g) = 0.04 dex, and σ([Fe/H]) = 0.09 dex, respectively.
Increasing the Self-Confidence of School Nurses to Provide Mental Health Care to Students
Authors: McKay Elizabeth Anne , Lim Eunjung , Mattheus Deborah 
Published: December 2024

Background
School nurses want and need continued education in student mental health care because of variability in their knowledge, skills, and confidence in assessing and responding to mental health concerns. To address this concern, two student mental health simulation scenarios were developed for a large school-based health program in Hawaii.

Method

School nurses (
n
= 51) participated in a 1-day skills training that included two scenarios with actors depicting students presenting with depression or anxiety. This mixed methods study used a qualitative component to explore nurses' simulation experiences and a six-item survey to assess confidence levels pre- and postsimulation.

Results
Scores for all six confidence items showed significant improvement after the intervention. Nurses highly valued the live actors and feedback sessions.

Conclusion

Mental health care simulations can significantly increase school nurses' confidence in providing appropriate assessments and follow-up care to students.

[
J Contin Educ Nurs.
2025;56(1):20–26.]
Companionship during Childbirth: Pregnant Women’s Perception, Acceptability, and Preferences in a Tertiary Health Center in Northwestern Nigeria
Authors: Garba Jamila Abubakar , Abdullahi Zainab Kontagora , Bello Saratu , Panti Abubakar Abubakar , Umar Amina Gambo , Tunau Karima Abubakar 
Published: December 2024

Background and Aim:
Companionship during childbirth has been identified as one of the indicators of quality of care during labor. Women who received companionship throughout labor have been found to have better outcome. The aim of this study was to determine the pregnant women’s perception, acceptability, and preferences for companionship during childbirth.

Materials and Methods:
This was a cross-sectional study among pregnant women attending antenatal care at a tertiary health center in Northwestern Nigeria. The data were obtained using an interviewer-administered questionnaire. Analysis was done using SPSS version 25.

Results:
Three hundred and forty-three respondents were recruited into the study. Among them, 193 (56.3%) were aware that they could have a companion during childbirth and 62 (18.1%) had a previous companion. Mothers were the companions for 19 (30.6%) and husbands were the companions for 16 (25.8%). The majority of the respondents (n = 243; 70.8%) believed that it is essential to have a companion during childbirth and 68.2% would accept having a companion during childbirth. The factors that were associated with the acceptability of having a companion during childbirth were educational status (P = 0.003) and awareness of companionship during childbirth (P < 0.001).

Conclusion:
The majority of the respondents believed that it is essential to have a companion during childbirth and are willing to accept it. The factors associated with the acceptability of having a companion during childbirth were educational status and awareness of companionship during childbirth.