bluuebunny/crossref_metadata_2025_split huggingface dataset:
Change-point Detection and Image Segmentation for Time Series of Astrophysical Images
Authors: Xu Cong , Günther Hans Moritz , Kashyap Vinay L. , Lee Thomas C. M. , Zezas Andreas 
Published: March 2021

Abstract
Many astrophysical phenomena are time-varying, in the sense that their intensity, energy spectrum, and/or the spatial distribution of the emission suddenly change. This paper develops a method for modeling a time series of images. Under the assumption that the arrival times of the photons follow a Poisson process, the data are binned into 4D grids of voxels (time, energy band, and x-y coordinates), and viewed as a time series of non-homogeneous Poisson images. The method assumes that at each time point, the corresponding multiband image stack is an unknown 3D piecewise constant function including Poisson noise. It also assumes that all image stacks between any two adjacent change points (in time domain) share the same unknown piecewise constant function. The proposed method is designed to estimate the number and the locations of all of the change points (in time domain), as well as all of the unknown piecewise constant functions between any pairs of the change points. The method applies the minimum description length principle to perform this task. A practical algorithm is also developed to solve the corresponding complicated optimization problem. Simulation experiments and applications to real data sets show that the proposed method enjoys very promising empirical properties. Applications to two real data sets, the XMM observation of a flaring star and an emerging solar coronal loop, illustrate the usage of the proposed method and the scientific insight gained from it.
The HOSTS Survey: Evidence for an Extended Dust Disk and Constraints on the Presence of Giant Planets in the Habitable Zone of β Leo
Authors: Defrère D. , Hinz P. M. , Kennedy G. M. , Stone J. , Rigley J. , Ertel S. , Gaspar A. , Bailey V. P. , Hoffmann W. F. , Mennesson B. , Millan-Gabet R. , Danchi W. C. , Absil O. , Arbo P. , Beichman C , Bonavita M , Brusa G. , Bryden G. , Downey E. C. , Esposito S. , Grenz P. , Haniff C. , Hill J. M. , Leisenring J. M. , Males J. R. , McMahon T. J. , Montoya M. , Morzinski K. M. , Pinna E. , Puglisi A. , Rieke G. , Roberge A. , Rousseau H. , Serabyn E. , Spalding E. , Skemer A. J. , Stapelfeldt K. , Su K. , Vaz A. , Weinberger A. J. , Wyatt M. C. 
Published: March 2021

Abstract
The young (50–400 Myr) A3V star β Leo is a primary target to study the formation history and evolution of extrasolar planetary systems as one of the few stars with known hot (∼1600 K), warm (∼600 K), and cold (∼120 K) dust belt components. In this paper, we present deep mid-infrared measurements of the warm dust brightness obtained with the Large Binocular Telescope Interferometer (LBTI) as part of its exozodiacal dust survey (HOSTS). The measured excess is 0.47% ± 0.050% within the central 1.5 au, rising to 0.81% ± 0.026% within 4.5 au, outside the habitable zone of β Leo. This dust level is 50 ± 10 times greater than in the solar system’s zodiacal cloud. Poynting–Robertson drag on the cold dust detected by Spitzer, and Herschel underpredicts the dust present in the habitable zone of β Leo, suggesting an additional delivery mechanism (e.g., comets) or an additional belt at ∼5.5 au. A model of these dust components is provided that implies the absence of planets more than a few Saturn masses between ∼5 au and the outer belt at ∼40 au. We also observationally constrain giant planets with the LBTI imaging channel at 3.8 μm wavelength. Assuming an age of 50 Myr, any planet in the system between approximately 5–50 au must be less than a few Jupiter masses, consistent with our dust model. Taken together, these observations showcase the deep contrasts and detection capabilities attainable by the LBTI for both warm exozodiacal dust and giant exoplanets in or near the habitable zone of nearby stars.
Consequences for the Scalar Field Dark Matter Model from the McGaugh Observed-baryon Acceleration Correlation
Authors: Padilla Luis E. , Solís-López Jordi , Matos Tonatiuh , Avilez-López Ana A. 
Published: March 2021

Abstract
Although the standard cosmological model, the so-called Λ cold dark matter (ΛCDM), appears to fit well observations at the cosmological level, it is well known that it possesses several inconsistencies at the galactic scales. In order to address the problems of the ΛCDM on a small scale, some alternative models have been proposed. Among the most popular candidates, the proposal that dark matter in the universe is made of ultralight bosons is a strong candidate today. For this work, we study through an analytical approach the consequences arising from comparing the Spitzer Photometry and Accurate Rotation Curves catalog observed-baryon acceleration correlation with the scalar field dark matter model. We carry out such analysis either considering the features of galactic halos extracted from structure-formation simulations or considering the existence of other non-dark-matter elements in the whole system (such as baryons or a supermassive black hole). Specifically, we address a recent claim that the model is not capable of reproducing a constant surface density in the core, in contrast to what observations suggest for a host of galaxies with different sizes and morphologies. In this direction, we show that this discrepancy can be alleviated once the contributions of non-dark-matter constituents in the whole galactic system are taken into account. Additionally, we find that a mass of m ≃ 1.41 × 10−22 eV/c
2 is capable of reproducing all of our findings and correctly adjusting the rotation curves coming from the Milky Way galaxy.
Asymmetrical Mass Ejection from Proto-white Dwarfs and the Formation of Eccentric Millisecond Pulsar Binaries
Authors: Han Qin , Li Xiang-Dong 
Published: March 2021

Abstract
Binary millisecond pulsars (MSPs) are believed to have descended from low-mass X-ray binaries (LMXBs), which have experienced substantial mass transfer and tidal circularization. Therefore, they should have very circular orbits. However, the discovery of several eccentric binary MSPs (with eccentricity e ∼ 0.01–0.1) challenges this standard picture. Three models have been proposed thus far based on accretion-induced collapse of massive white dwarfs (WDs), neutron star–strange star transition, and formation of circumbinary disks. All of them are subject to various uncertainties and are not entirely consistent with observations. Here, we propose an alternative model that takes into account the influence of thermonuclear flashes on proto-WDs. We assume that the flashes lead to asymmetrical mass ejection, which imparts a mild kick to the proto-WDs. By simulating orbital changes of binary MSPs with multiple shell flashes, we show that it is possible to reproduce the observed eccentricities, provided that the kick velocities are around a few km s−1.
The Large-scale Magnetic Field Advected in the Corona of a Thin Accretion Disk
Authors: Li Jia-wen , Cao Xinwu 
Published: March 2021

Abstract
Large-scale magnetic field is believed to play a key role in launching and collimating jets/outflows. It was found that advection of the external field by a geometrically thin disk is rather inefficient, while the external weak field may be dragged inwards by fast radially moving tenuous and/or hot gas above the thin disk. We investigate the field advection in a thin (cold) accretion disk covered with hot corona, in which turbulence is responsible for the angular momentum transfer of the gas in the disk and corona. The radial velocity of the gas in the corona is significantly higher than that in the thin disk. Our calculations show that the external magnetic flux is efficiently transported inwards by the corona, and the field line is strongly inclined toward the disk surface, which helps to launch outflows. The field configurations are consistent with those observed in the numerical simulations. The strength of the field is substantially enhanced in the inner region of the disk (usually several orders of magnitude higher than the external field strength), which is able to drive a fraction of gas in the corona into outflows. This mechanism may be useful in explaining the observational features in X-ray binaries and active galactic nuclei. Our results may help in understanding the physics of the magnetohydrodynamic simulations.
Origin of Weak Mg ii and Higher-ionization Absorption Lines in Outflows from Intermediate-redshift Dwarf Galaxies
Authors: Fujita Akimi , Misawa Toru , Charlton Jane C. , Meiksin Avery , Low Mordecai-Mark Mac 
Published: March 2021

Abstract
Observations at intermediate redshifts reveal the presence of numerous compact, weak Mg ii absorbers with near to supersolar metallicities, often surrounded by extended regions that produce C iv and/or O vi absorption, in the circumgalactic medium at large impact parameters from luminous galaxies. Their origin and nature remain unclear. We hypothesize that undetected satellite dwarf galaxies are responsible for producing some of these weak Mg ii absorbers. We test our hypothesis using gas dynamical simulations of galactic outflows from a dwarf galaxy with a halo mass of 5 × 109
M
⊙, as might be falling into a larger L* halo at z = 2. We find that thin, filamentary, weak Mg ii absorbers (≲100 pc) are produced in two stages: (1) when shocked core-collapse supernova (SN II)–enriched gas descending in a galactic fountain gets shock compressed by upward flows driven by subsequent SN II and cools (phase 1) and, later, (2) during an outflow driven by Type Ia supernovae that shocks and sweeps up pervasive SN II–enriched gas, which then cools (phase 2). The Mg ii absorbers in our simulations are continuously generated by shocks and cooling with moderate metallicity ∼0.1–0.2 Z
⊙ but low column density <1012 cm−2. They are also surrounded by larger (0.5–1 kpc) C iv absorbers that seem to survive longer. Larger-scale (>1 kpc) C iv and O vi clouds are also produced in both expanding and shocked SN II–enriched gas. Observable ion distributions from our models appear well converged at our standard resolution (12.8 pc). Our simulation highlights the possibility of dwarf galactic outflows producing highly enriched multiphase gas.
Constraints on Nuclear Saturation Properties from Terrestrial Experiments and Astrophysical Observations of Neutron Stars
Authors: Choi Soonchul , Miyatsu Tsuyoshi , Cheoun Myung-Ki , Saito Koichi 
Published: March 2021

Abstract
Taking into account the terrestrial experiments and the recent astrophysical observations of neutron stars and gravitational-wave signals, we impose restrictions on the equation of state (EoS) for isospin-asymmetric nuclear matter. Using the relativistic mean-field model with SU(3) flavor symmetry, we investigate the impacts of effective nucleon mass, nuclear incompressibility, and slope parameter of nuclear symmetry energy on the nuclear and neutron star properties. It is found that the astrophysical information of massive neutron stars and tidal deformabilities, as well as the nuclear experimental data, plays an important role to restrict the EoS for neutron stars. In particular, the softness of the nuclear EoS due to the existence of hyperons in the core gives stringent constraints on those physical quantities. Furthermore, it is possible to put limits on the curvature parameter of nuclear symmetry energy by means of nuclear and astrophysical calculations.
Emission Properties of Periodic Fast Radio Bursts from the Motion of Magnetars: Testing Dynamical Models
Authors: Li Dongzi , Zanazzi J. J. 
Published: March 2021

Abstract
Recent observations of the periodic fast radio burst source 180916.J0158+65 (FRB 180916) find small linear polarization position angle swings during and between bursts, with a burst activity window that becomes both narrower and earlier at higher frequencies. Although the observed chromatic activity window disfavors models of periodicity in FRB 180916 driven solely by the occultation of a neutron star by the optically thick wind from a stellar companion, the connection to theories where periodicity arises from the motion of a bursting magnetar remains unclear. In this Letter, we show how altitude-dependent radio emission from a magnetar, with bursts emitted from regions that are asymmetric with respect to the magnetic dipole axis, can lead to burst activity windows and polarization consistent with the recent observations. In particular, the fact that bursts arrive systematically earlier at higher frequencies disfavors theories where the FRB periodicity arises from forced precession of a magnetar by a companion or fallback disk, but is consistent with theories where periodicity originates from a slowly rotating or freely precessing magnetar. Several observational tests are proposed to verify/differentiate between the remaining theories, and pin down which theory explains the periodicity in FRB 180916.
Orbital Clustering Identifies the Origins of Galactic Stellar Streams
Authors: Bonaca Ana , Naidu Rohan P. , Conroy Charlie , Caldwell Nelson , Cargile Phillip A. , Han Jiwon Jesse , Johnson Benjamin D. , Kruijssen J. M. Diederik , Myeong G. C. , Speagle Joshua S. , Ting Yuan-Sen , Zaritsky Dennis 
Published: March 2021

Abstract
The origins of most stellar streams in the Milky Way are unknown. With improved proper motions provided by Gaia EDR3, we show that the orbits of 23 Galactic stellar streams are highly clustered in orbital phase space. Based on their energies and angular momenta, most streams in our sample can plausibly be associated with a specific (disrupted) dwarf galaxy host that brought them into the Milky Way. For eight streams we also identify likely globular cluster progenitors (four of these associations are reported here for the first time). Some of these stream progenitors are surprisingly far apart, displaced from their tidal debris by a few to tens of degrees. We identify stellar streams that appear spatially distinct, but whose similar orbits indicate they likely originate from the same progenitor. If confirmed as physical discontinuities, they will provide strong constraints on the mass loss from the progenitor. The nearly universal ex situ origin of existing stellar streams makes them valuable tracers of galaxy mergers and dynamical friction within the Galactic halo. Their phase-space clustering can be leveraged to construct a precise global map of dark matter in the Milky Way, while their internal structure may hold clues to the small-scale structure of dark matter in their original host galaxies.
Rapidly Varying Anisotropic Methanol (CH3OH) Production in the Inner Coma of Comet 46P/Wirtanen as Revealed by the ALMA Atacama Compact Array
Authors: Roth Nathan X. , Milam Stefanie N. , Cordiner Martin A. , Bockelée-Morvan Dominique , DiSanti Michael A. , Boissier Jérémie , Biver Nicolas , Crovisier Jacques , Russo Neil Dello , Bonev Boncho P. , Qi Chunhua , Remijan Anthony J. , Charnley Steven B. , Gibb Erika L. , Val-Borro Miguel de , Jehin Emmanuël 
Published: March 2021

Abstract
We report the detection of CH3OH emission in comet 46P/Wirtanen on UT 2018 December 8 and 9 using the Atacama Compact Array (ACA), part of the Atacama Large Millimeter/Submillimeter Array (ALMA). These interferometric measurements of CH3OH along with continuum emission from dust probed the inner coma (<2000 km from the nucleus) of 46P/Wirtanen approximately one week before its closest approach to Earth (Δ = 0.089–0.092 au), revealing rapidly varying and anisotropic CH3OH outgassing during five separate ACA executions between UT 23:57 December 7 and UT 04:55 December 9, with a clear progression in the spectral line profiles over a timescale of minutes. We present spectrally integrated flux maps, production rates, rotational temperatures, and spectral line profiles of CH3OH during each ACA execution. The variations in CH3OH outgassing are consistent with Wirtanen’s 9 hr nucleus rotational period derived from optical and millimeter wavelength measurements and thus are likely coupled to the changing illumination of active sites on the nucleus. The consistent blue offset of the line center indicates enhanced CH3OH sublimation from the sunward hemisphere of the comet, perhaps from icy grains. These results demonstrate the exceptional capabilities of the ACA for time-resolved measurements of comets such as 46P/Wirtanen.
Secukinumab Efficacy on Enthesitis in Patients With Ankylosing Spondylitis: Pooled Analysis of Four Pivotal Phase III Studies
Authors: Schett Georg , Baraliakos Xenofon , Van den Bosch Filip , Deodhar Atul , Østergaard Mikkel , Gupta Ayan Das , Mpofu Shephard , Fox Todd , Winseck Adam , Porter Brian , Shete Abhijit , Gensler Lianne S. 
Published: March 2021

ObjectiveTo assess the efficacy of secukinumab on axial and peripheral enthesitis in patients with ankylosing spondylitis (AS) using pooled data from randomized controlled phase III studies.MethodsIn this posthoc analysis, data were pooled from patients originally randomized to secukinumab 150 mg, 300 mg, or placebo (PBO) from phase III MEASURE 1–4 studies (ClinicalTrials.gov: NCT01358175, NCT01649375, NCT02008916, and NCT02159053). Maastricht AS Enthesitis Score (MASES) was used for assessments of enthesitis through Week 52. Efficacy outcomes were mean change in MASES score and complete resolution (MASES = 0) of enthesitis in patients with baseline MASES > 0.ResultsA total of 693 (71.5%) patients had enthesitis at baseline in secukinumab 300 mg, 150 mg, and PBO groups (58 [76.3%], 355 [70.4%], and 280 [72%], respectively) out of 969 patients pooled in this analysis. At Week 16, mean changes from baseline for overall MASES and enthesitis at axial MASES sites, respectively, were as follows: –2.9 (P < 0.01) and –2.9 (P < 0.01) for secukinumab 300 mg; –2.4 (P < 0.015) and –2.3 (P < 0.05) for secukinumab 150 mg; and –1.9 and –1.8 for PBO, with improvements seen through Week 52. More than one-third of secukinumab-treated patients (300 mg: 36.2%; 150 mg: 40.8%) achieved complete resolution of enthesitis at Week 16.ConclusionSecukinumab improved enthesitis at overall MASES and axial sites in patients with AS.
Entre investissement personnel et coopération avec les professionnels : ce que disent les parents de l’orientation professionnelle des adolescents et jeunes adultes en situation de « handicap rare » versus « non rare »
Authors: Hugon Mandarine , Joselin Laurence , Toubhans Marie-Pierre 
Published: March 2021

L’orientation professionnelle constitue un élément important dans la vie des jeunes mais aussi vis-à-vis des attentes parentales. Il paraît alors essentiel d’interroger le point de vue des parents de jeunes en situation de handicap, sur les leviers et difficultés qu’ils ont pu rencontrer pour accompagner leur adolescent, à l’heure de la société dite inclusive . Vingt et un entretiens semi-directifs ont été réalisés auprès de parents ayant un enfant en situation de « handicap rare » ou « non rare ». Si l’analyse comparative des entretiens ne montre pas de différence majeure dans les discours, la coopération entre familles et professionnels est interrogée, notamment dans la recherche de l’épanouissement identitaire et social des jeunes en situation de handicap. Enfin, le fort investissement des parents questionne les enjeux du soutien à la parentalité pour l’avenir du jeune.
La fidélité d’implantation : un facteur de l’efficacité des formations parentales en trouble du spectre de l’autisme
Authors: Rousseau Myriam , McKinnon Suzie , Bourassa Jacinthe , Paquet Annie , Clément Céline 
Published: March 2021

L’ABC du comportement d’enfants ayant un TSA : des parents en action ! est un programme s’adressant aux parents d’enfants ayant un trouble du spectre de l’autisme. Malgré les effets positifs documentés, ce programme, tout comme un bon nombre de programmes rencontre des défis lors de son application en contexte d’intervention. Cet article s’intéresse à la fidélité d’implantation de ce programme au Québec. Un total de 17 animatrices et 52 parents ont participé à la recherche. Les résultats tendent à démontrer la fidélité d’implantation du programme et permettent d’identifier des conditions facilitant et freinant sa mise en place. Ces résultats sont susceptibles d’intéresser les établissements désireux d’implanter des nouvelles interventions. Ceux-ci devant être au fait de l’importance de procéder à une évaluation rigoureuse de la fidélité d’implantation d’un programme avant même de penser à ses retombées.
La capacité d’être libre
Authors: Chevalier Julie 
Published: March 2021

Cet article conceptualise la capacité d’être libre depuis ce que je nomme un effondrement de la crainte dans la situation analytique, complémentairement à la crainte de l’effondrement théorisée par Winnicott. Cette approche se décale d’une idéologie contemporaine d’une psyché a-conflictuelle afin d’interroger, dans notre hypermodernité, l’articulation de défaillances environnementales, familiale, sociale et politique. J’émets l’hypothèse qu’un effondrement de la crainte procède de la destruction fantasmatique d’une partie du moi idéalisée de l’analysant par l’analyste, ce qui suppose sa fonction paternelle haineuse dans la dynamique transféro-contre-transférentielle. Cela montre comment la capacité à survivre du sujet, dans son rapport tout particulier à la haine objective de l’analyste, permet la rencontre nécessaire de son « vrai » moi. La capacité d’être libre suppose ainsi que l’analyste incarne les fonctions de l’environnement. Deux vignettes cliniques illustrent mon propos.
Libertés et contraintes du culturel
Authors: Konicheckis Alberto 
Published: March 2021

Le culturel impose des liens qui entravent les possibilités individuelles de liberté. Ces liens ne se réduisent pas seulement à l’extériorité d’un environnement qui restreindrait, du dehors, les désirs individuels internes. Des modalités fondatrices et potentiellement aliénantes du culturel dans le psychisme individuel sont explorées à travers les liens précoces et dans la psychologie des foules, où, en toute dé-subjectivation, l’individu exprime ses pulsions les plus rudimentaires. Elles sont également abordées dans des formations psychiques collectives comme le contrat narcissique et les alliances inconscientes. Un personnage central dans l’analyse de Nora permet de rendre évidente la condensation de différentes lignes de force qui, dans l’essence même du psychisme, œuvrent pour l’entrave de la liberté : l’interdit œdipien, la recherche d’un sentiment primaire de toute-puissance et les appartenances culturelles.
Histoires conjuguées. Analyste, institution et Révolution
Authors: Chahoury Charabaty Mona 
Published: March 2021

L’auteure procède à un survol, en parallèle, de sa double expérience institutionnelle et personnelle : dans l’Association libanaise pour le développement de la psychanalyse (ALDeP), sa fondation et son évolution d’une part, et son propre cheminement, d’autre part. Elle évoque, entre autres, la question du développement institutionnel du groupe dans sa dynamique et son interaction avec le Comité de parrainage de l’IPA. L’émigration de l’auteure en Amérique du Nord et sa recherche d’une formation psychanalytique sur place dans un pays européen ont diversifié son bagage théorico-clinique et lui ont permis une certaine distance dans l’appréhension de son double cheminement analytique personnel et institutionnel. Elle termine son texte avec l’actualité de la révolution dans le pays d’implantation de l’association et ses conséquences sur la pratique analytique et le vécu groupal des membres et des analystes en formation.