bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bethe–Heitler Signature in Proton Synchrotron Models for Gamma-Ray Bursts
Authors: Bégué D. , Samuelsson F. , Pe’er A. 
Published: October 2022

Abstract
We study the effect of Bethe–Heitler (BeHe) pair production on a proton synchrotron model for the prompt emission in gamma-ray bursts (GRBs). The possible parameter space of the model is constrained by consideration of the synchrotron radiation from the secondary BeHe pairs. We find two regimes of interest. (1) At high bulk Lorentz factor, large radius, and low luminosity, proton synchrotron emission dominates and produces a spectrum in agreement with observations. For part of this parameter space, a subdominant (in the MeV band) power law is created by the synchrotron emission of the BeHe pairs. This power law extends up to few tens or hundreds of MeV. Such a signature is a natural expectation in a proton synchrotron model, and it is seen in some GRBs, including GRB 190114C recently observed by the MAGIC observatory. (2) At low bulk Lorentz factor, small radius, and high luminosity, BeHe cooling dominates. The spectrum achieves the shape of a single power law with spectral index α = −3/2 extending across the entire Gamma-ray Burst Monitor/Swift energy window, incompatible with observations. Our theoretical results can be used to further constrain the spectral analysis of GRBs in the guise of proton synchrotron models.
Exploring the Limits of Synthetic Creation of Solar EUV Images via Image-to-image Translation
Authors: Salvatelli Valentina , dos Santos Luiz F. G. , Bose Souvik , Neuberg Brad , Cheung Mark C. M. , Janvier Miho , Jin Meng , Gal Yarin , Güneş Baydin Atilim 
Published: October 2022

Abstract
The Solar Dynamics Observatory (SDO), a NASA multispectral decade-long mission that has been daily producing terabytes of observational data from the Sun, has been recently used as a use case to demonstrate the potential of machine-learning methodologies and to pave the way for future deep space mission planning. In particular, the idea of using image-to-image translation to virtually produce extreme ultraviolet channels has been proposed in several recent studies, as a way to both enhance missions with fewer available channels and to alleviate the challenges due to the low downlink rate in deep space. This paper investigates the potential and the limitations of such a deep learning approach by focusing on the permutation of four channels and an encoder–decoder based architecture, with particular attention to how morphological traits and brightness of the solar surface affect the neural network predictions. In this work we want to answer the question: can synthetic images of the solar corona produced via image-to-image translation be used for scientific studies of the Sun? The analysis highlights that the neural network produces high-quality images over 3 orders of magnitude in count rate (pixel intensity) and can generally reproduce the covariance across channels within a 1% error. However, the model performance drastically diminishes in correspondence to extremely high energetic events like flares, and we argue that the reason is related to the rareness of such events posing a challenge to model training.
Detection of Ubiquitous Weak and Impulsive Nonthermal Emissions from the Solar Corona
Authors: Sharma Rohit , Oberoi Divya , Battaglia Marina , Krucker Säm 
Published: October 2022

Abstract
A ubiquitous presence of weak energy releases is one of the most promising hypotheses to explain coronal heating, referred to as the nanoflare hypothesis. The accelerated electrons associated with such weak heating events are also expected to give rise to coherent impulsive emission via plasma instabilities in the meterwave radio band, making this a promising spectral window to look for their presence. Recently Mondal et al. reported the presence of weak and impulsive emissions from quiet Sun regions which seem to meet the requirements of being radio counterparts of the hypothesized nanoflares. Detection of such low-contrast weak emission from the quiet Sun is challenging and, given their implications, it is important to confirm their presence. In this work, using data from the Murchison Widefield Array, we explore the use of an independent robust approach for their detection by separating the dominant, slowly varying component of emission from the weak impulsive one in the visibility domain. We detect milli-Solar Flux Unit-level bursts taking place all over the Sun and characterize their brightness temperatures, distributions, morphologies, durations, and associations with features seen in extreme-UV images. We also attempt to constrain the energies of the nonthermal particles using inputs from the FORWARD coronal model along with some reasonable assumptions, and find them to lie in the subpico flare (∼1019–1021 erg) range. In the process, we also discover perhaps the weakest type III radio burst and another that shows clear signatures of the weakest quasi-periodic pulsations.
The 2020 Eclipse of R Aquarii in the Near-infrared: Mid-eclipse Observations of Disk Distress
Authors: Hinkle Kenneth H. , Brittain Sean , Fekel Francis C. , Lebzelter Thomas , Boogert Adwin 
Published: October 2022

Abstract
The Mira in the bright, dusty, symbiotic binary R Aquarii undergoes eclipses of multiyear duration every ∼44 yr by a large, opaque accretion disk. The 2020 eclipse was confirmed by I-band photometry. High-resolution M- and K-band spectra were observed near the midpoint of the eclipse, in 2020 August and September. The 4.5–5.5 μm spectrum during eclipse is a complex blend of disk and Mira features. Continuum emission from the disk region contributes to both the 2.3 μm and 4.6 μm region. The lowest energy vibration-rotation CO lines contain multiple absorption features from ∼780 K gas flowing across the disk away from the Mira. CO fundamental and overtone emission lines are also present. The eccentricity of the orbit results in significant orbital variation in the size of the Roche lobes. At periastron the Roche radius of the secondary is ∼4.0 au, smaller than both the 5 au geometric radius for the disk and estimates for the disk size from models. Fundamental band CO 2–1 emission originates from a thin, eccentric ring with inner radius ∼4.75 au and outer radius ∼6.9 au. The CO emission is identified with regions where the disk has been disrupted near the time of periastron. CO 3–2 fundamental band lines and low-excitation lines in the CO 2–0 and 3–1 overtone bands originate in a Mira-facing spot, 6.3 au from the accretion disk center, near the inner Lagrange point.
SDSS-IV MaNGA: Unveiling Galaxy Interaction by Merger Stages with Machine Learning
Authors: Chang Yu-Yen , Lin Lihwai , Pan Hsi-An , Lin Chieh-An , Hsieh Bau-Ching , Bottrell Connor , Wang Pin-Wei 
Published: October 2022

Abstract
We use machine-learning techniques to classify galaxy merger stages, which can unveil physical processes that drive the star formation and active galactic nucleus (AGN) activities during galaxy interaction. The sample contains 4690 galaxies from the integral field spectroscopy survey SDSS-IV MaNGA and can be separated into 1060 merging galaxies and 3630 nonmerging or unclassified galaxies. For the merger sample, there are 468, 125, 293, and 174 galaxies (1) in the incoming pair phase, (2) in the first pericentric passage phase, (3) approaching or just passing the apocenter, and (4) in the final coalescence phase or post-mergers. With the information of projected separation, line-of-sight velocity difference, Sloan Digital Sky Survey (SDSS) gri images, and MaNGA Hα velocity map, we are able to classify the mergers and their stages with good precision, which is the most important score to identify interacting galaxies. For the two-phase classification (binary; nonmerger and merger), the performance can be high (precision > 0.90) with LGBMClassifier. We find that sample size can be increased by rotation, so the five-phase classification (nonmerger, and merger stages 1, 2, 3, and 4) can also be good (precision > 0.85). The most important features come from SDSS gri images. The contribution from the MaNGA Hα velocity map, projected separation, and line-of-sight velocity difference can further improve the performance by 0%–20%. In other words, the image and the velocity information are sufficient to capture important features of galaxy interactions, and our results can apply to all the MaNGA data, as well as future all-sky surveys.
Dusty, Self-obscured Transients from Stellar Coalescence
Authors: MacLeod Morgan , De Kishalay , Loeb Abraham 
Published: October 2022

Abstract
We discuss the central role that dust condensation plays in shaping the observational appearance of outflows from coalescing binary systems. As binaries begin to coalesce, they shock-heat and expel material into their surroundings. Depending on the properties of the merging system, this material can expand to the point where molecules and dust form, dramatically increasing the gas opacity. We use the existing population of luminous red novae to constrain the thermodynamics of these ejecta, then apply our findings to the progressive obscuration of merging systems in the lead up to their coalescence. Compact progenitor stars near the main sequence or in the Hertzsprung gap along with massive progenitor stars have sufficiently hot circumstellar material to remain unobscured by dust. By contrast, more extended, low-mass giants should become completely optically obscured by dust formation in the circumbinary environment. We predict that 30%–50% of stellar-coalescence transients for solar-mass stars will be dusty, infrared-luminous sources. Of these, the optical transients may selectively trace complete merger outcomes while the infrared transients trace common envelope ejection outcomes.
The Location and Angle Distribution of Magnetic Reconnection in the Solar Corona
Authors: Knizhnik Kalman J. , Cabral-Pelletier Logan C. 
Published: October 2022

Abstract
A major unresolved issue in solar physics is the nature of the reconnection events that may give rise to the extreme temperatures measured in the solar corona. In the nanoflare heating paradigm of coronal heating, localized reconnection converts magnetic energy into thermal energy, producing multithermal plasma in the corona. The properties of the corona produced by magnetic reconnection, however, depend on the details of the reconnection process. A significant challenge in understanding the details of reconnection in magnetohydrodynamic (MHD) models is that these models are frequently only able to tell us that reconnection has occurred, but there is significant difficulty in identifying precisely where and when it occurred. In order to properly understand the consequences of reconnection in MHD models, it is crucial to identify reconnecting field lines and where along the field lines reconnection occurs. In this work, we analyze a fully 3D MHD simulation of a realistic sunspot topology, driven by photospheric motions, and we present a model for identifying reconnecting field lines. We also present a proof-of-concept model for identifying the location of reconnection along the reconnecting field lines, and use that to measure the angle at which reconnection occurs in the simulation. We find evidence that magnetic reconnection occurs preferentially near field line footpoints, and discuss the implications of this for coronal heating models.
Exponential Fluctuations in the Modes of Orthogonal Polarization in Pulsar Radio Emission
Authors: McKinnon M. M. 
Published: October 2022

Abstract
A statistical model for the polarization of pulsar radio emission is enhanced to account for the heavy modulation of the emission, the possible covariance of the Stokes parameters, and the observed asymmetries in the distributions of total intensity, polarization, and fractional polarization, by treating the intensities of the orthogonal polarization modes as exponential random variables. The model is used to derive theoretical distributions to compare with what is observed. The resulting distributions are unimodal and generally asymmetric. The unimodality arises from the model’s fundamental assumption that the orthogonal modes are superposed. The asymmetry originates primarily from different fluctuations in mode intensities. The distributions of fractional polarization are truncated at the degree of linear and circular polarization intrinsic to the modes. A number of observable parameters that quantify the statistical properties of the emission and its polarization are derived and are shown to be functions only of the ratio of the modes’ mean intensities, M, suggesting their spectra coevolve according to the frequency dependence of M. This particular implementation of the model requires the modes to fluctuate differently in order to replicate the observations. Given that a single underlying emission mechanism seems unlikely to selectively modulate the mode intensities, the different fluctuations are attributed either to different emission mechanisms for the modes or to mode-dependent propagation or scattering effects in the pulsar magnetosphere.
A Comprehensive Radiative Magnetohydrodynamics Simulation of Active Region Scale Flux Emergence from the Convection Zone to the Corona
Authors: Chen Feng , Rempel Matthias , Fan Yuhong 
Published: October 2022

Abstract
We present a comprehensive radiative magnetohydrodynamic simulation of the quiet Sun and large solar active regions. The 197 Mm wide simulation domain spans from 18(10) Mm beneath the photosphere to 113 Mm in the solar corona. Radiative transfer assuming local thermal equilibrium, optically thin radiative losses, and anisotropic conduction transport provide the necessary realism for synthesizing observables to compare with remote-sensing observations of the photosphere and corona. This model self-consistently reproduces observed features of the quiet Sun, emerging and developed active regions, and solar flares up to M class. Here, we report an overview of the first results. The surface magneto-convection yields an upward Poynting flux that is dissipated in the corona and heats the plasma to over 1 MK. The quiescent corona also presents ubiquitous propagating waves, jets, and bright points with sizes down to 2 Mm. Magnetic flux bundles emerge into the photosphere and give rise to strong and complex active regions with over 1023 Mx magnetic flux. The coronal free magnetic energy, which is approximately 18% of the total magnetic energy, accumulates to approximately 1033 erg. The coronal magnetic field is clearly non-force-free, as the Lorentz force needs to balance the pressure force and viscous stress as well as drive magnetic field evolution. The emission measure from

log

10

T
=
4.5

to

log

10

T
>
7

provides a comprehensive view of the active region corona, such as coronal loops of various lengths and temperatures, mass circulation by evaporation and condensation, and eruptions from jets to large-scale mass ejections.
The LSST Era of Supermassive Black Hole Accretion Disk Reverberation Mapping
Authors: Kovačević Andjelka B. , Radović Viktor , Ilić Dragana , Popović Luka Č. , Assef Roberto J. , Sánchez-Sáez Paula , Nikutta Robert , Raiteri Claudia M. , Yoon Ilsang , Homayouni Yasaman , Li Yan-Rong , Caplar Neven , Czerny Bozena , Panda Swayamtrupta , Ricci Claudio , Jankov Isidora , Landt Hermine , Wolf Christian , Kovačević-Dojčinović Jelena , Lakićević Maša , Savić Đorđe V. , Vince Oliver , Simić Saša , Čvorović-Hajdinjak Iva , Marčeta-Mandić Sladjana 
Published: October 2022

Abstract
The Vera C. Rubin Observatory’s Legacy Survey of Space and Time (LSST) will detect an unprecedentedly large sample of actively accreting supermassive black holes with typical accretion disk (AD) sizes of a few light days. This brings us to face challenges in the reverberation mapping (RM) measurement of AD sizes in active galactic nuclei using interband continuum delays. We examine the effect of LSST cadence strategies on AD RM using our metric AGN_TimeLagMetric. It accounts for redshift, cadence, the magnitude limit, and magnitude corrections for dust extinction. Running our metric on different LSST cadence strategies, we produce an atlas of the performance estimations for LSST photometric RM measurements. We provide an upper limit on the estimated number of quasars for which the AD time lag can be computed within 0 < z < 7 using the features of our metric. We forecast that the total counts of such objects will increase as the mean sampling rate of the survey decreases. The AD time lag measurements are expected for >1000 sources in each deep drilling field (DDF; (10 deg2)) in any filter, with the redshift distribution of these sources peaking at z ≈ 1. We find the LSST observation strategies with a good cadence (≲5 days) and a long cumulative season (∼9 yr), as proposed for LSST DDF, are favored for the AD size measurement. We create synthetic LSST light curves for the most suitable DDF cadences and determine RM time lags to demonstrate the impact of the best cadences based on the proposed metric.
L’identité de genre – une approche métapsychologique
Authors: Heenen-Wolff Susann 
Published: October 2022

Classiquement, la transsexualité ou la « transidentité » 1 a été considérée comme l’expression d’un trouble grave de la personnalité, et depuis 2013 comme « dysphorie de genre » (DSM5). Il semble que des personnes qui disposent d’un fonctionnement psychique de type névrotique peuvent aspirer à une réassignation sexuelle ; elles ne peuvent pas s’identifier à leur corps anatomique, alors qu’elles peuvent aimer, travailler, être créatives et maîtrisent la vie de tous les jours. L’auteure cherche à fournir une contribution métapsychologique quant à la genèse de l’identification de genre qui rend compréhensible ce fait.
Tou.tes queer, mais certain.es plus que d’autres
Authors: Detandt Sandrine , Pezeril Charlotte , Demart Sarah 
Published: October 2022

Nos subjectivités et positionnements passent aujourd’hui par l’opérateur du genre comme « nouvel » agent aussi bien conceptuel que politique ou discursif pour penser le sexe, permettant une libération des voix sur les inégalités et les minorités. Que valent les « vérités » sur les corps et leurs nominations lorsqu’il semblerait que tout ne serait que production normative et discursive ? Que reste-t-il du sujet, au sens psychanalytique du terme ? Dans quelle mesure ce sujet est-il queer, au sens d’une déconstruction radicale et d’une opposition à la norme ? Et quelles sont les conditions de possibilité d’un sujet politique queer dans une perspective plus globale et intersectionnelle ? L’objet de cet article, qui rend compte d’un dialogue en cours, est d’interroger, par le triple prisme de la psychologie, l’anthropologie et la sociologie ce qui de cette condition ne se dilue pas entièrement dans le social au regard des conditions de possibilité d’énonciation de subjectivités multiples, sinon infinies et peut-être jamais tout à fait achevées.
Salarié.es en procès
Authors: Lejeune Aude 
Published: October 2022

Alors que le recours aux avocat·es n’est pas obligatoire devant le conseil des prud’hommes, 85 % des justiciables y font appel. À partir d’une enquête auprès de salarié·es du secteur privé en procès, cet article montre que la remise de soi aux avocat·es et l’expérience de la procédure judiciaire, de l’introduction de la requête à la décision, transforment les attentes et représentations que les salarié·es se font de la justice comme institution au sein de laquelle faire valoir leurs droits.
La race, entre les Grecs et nous
Authors: Ismard Paulin 
Published: October 2022

La race a fait son entrée dans le lexique scientifique d’une partie des historiens des mondes grecs et romain. L’Antiquité gréco-romaine trouve désormais sa place dans de grandes synthèses scientifiques portant sur l’histoire de la race et du racisme, alors que plusieurs historiens et philologues entreprennent de révéler le rôle structurant joué par la race dans la culture et les sociétés antiques. Arraché à son contexte d’apparition, le monde euro-américain de l’âge moderne, la race se présente ainsi comme une catégorie universelle, susceptible d’éclairer des processus de discrimination potentiellement à l’œuvre dans toutes les sociétés. La démarche, qui se place dans le sillon de la théorie critique de la race, mérite d’être interrogée. Quel est le gain d’une telle montée en généralité, qui rend le concept de race disponible en tout lieu et en tout temps ? À quelles conditions est-il pertinent d’employer la notion de race pour décrire les sociétés civiques du monde grec antique ? Pour éclairer plus précisément les enjeux de la discussion, l’article considère une séquence particulière de l’histoire sociale et politique athénienne, dans laquelle plusieurs historiens ont vu l’acte de naissance d’une « citoyenneté raciale ».
E-Learning and Blended Learning Methodologies Used in Universities During and After COVID-19
Authors: Ghazal Ghadeer , Alian Marwah , Alkhawaldeh Eslam 
Published: October 2022

As a response to the COVID-19 pandemic, various e-learning platforms are being used in different universities. E-learning platforms such as Microsoft Teams, Zoom, Moodle, Google Classroom provides different features that may be helpful during the pandemic. In this research, the number of registered students, the activities held on e-learning platforms before, during, and after the pandemic are compared in Hashemite University as a case study. The analysis shows that the interaction between students and their lecturers has increased by more than 90% across all platforms at the Hashemite University during the pandemic. However, it has increased by 64% with the Moodle platform. The effect of three learning methods; face-to-face, blended, and online learning is examined and the preference of students investigated with courses’ categories such as remedial materials, collage requirements, specialization materials, and free materials. The students preferred online learning for remedial and free materials, with percentage values of 75% and 57%, respectively, but face-to-face learning is chosen for collage requirements and specialization materials, with percentage values of 54% and 78%, respectively.