bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evidence That the Directly Imaged Planet HD 131399 Ab Is a Background Star
Authors: Nielsen Eric L. , Rosa Robert J. De , Rameau Julien , Wang Jason J. , Esposito Thomas M. , Millar-Blanchaer Maxwell A. , Marois Christian , Vigan Arthur , Ammons S. Mark , Artigau Etienne , Bailey Vanessa P. , Blunt Sarah , Bulger Joanna , Chilcote Jeffrey , Cotten Tara , Doyon René , Duchêne Gaspard , Fabrycky Daniel , Fitzgerald Michael P. , Follette Katherine B. , Gerard Benjamin L. , Goodsell Stephen J. , Graham James R. , Greenbaum Alexandra Z. , Hibon Pascale , Hinkley Sasha , Hung Li-Wei , Ingraham Patrick , Jensen-Clem Rebecca , Kalas Paul , Konopacky Quinn , Larkin James E. , Macintosh Bruce , Maire Jérôme , Marchis Franck , Metchev Stanimir , Morzinski Katie M. , Murray-Clay Ruth A. , Oppenheimer Rebecca , Palmer David , Patience Jennifer , Perrin Marshall , Poyneer Lisa , Pueyo Laurent , Rafikov Roman R. , Rajan Abhijith , Rantakyrö Fredrik T. , Ruffio Jean-Baptiste , Savransky Dmitry , Schneider Adam C. , Sivaramakrishnan Anand , Song Inseok , Soummer Remi , Thomas Sandrine , Wallace J. Kent , Ward-Duong Kimberly , Wiktorowicz Sloane , Wolff Schuyler 
Published: November 2017

Abstract
We present evidence that the recently discovered, directly imaged planet HD 131399 Ab is a background star with nonzero proper motion. From new JHK1L′ photometry and spectroscopy obtained with the Gemini Planet Imager, VLT/SPHERE, and Keck/NIRC2, and a reanalysis of the discovery data obtained with VLT/SPHERE, we derive colors, spectra, and astrometry for HD 131399 Ab. The broader wavelength coverage and higher data quality allow us to reinvestigate its status. Its near-infrared spectral energy distribution excludes spectral types later than L0 and is consistent with a K or M dwarf, which are the most likely candidates for a background object in this direction at the apparent magnitude observed. If it were a physically associated object, the projected velocity of HD 131399 Ab would exceed escape velocity given the mass and distance to HD 131399 A. We show that HD 131399 Ab is also not following the expected track for a stationary background star at infinite distance. Solving for the proper motion and parallax required to explain the relative motion of HD 131399 Ab, we find a proper motion of 12.3 mas yr−1. When compared to predicted background objects drawn from a galactic model, we find this proper motion to be high but consistent with the top 4% fastest-moving background stars. From our analysis, we conclude that HD 131399 Ab is a background K or M dwarf.
Further Lunar Occultations from the 2.4 m Thai National Telescope
Authors: Richichi A. , Tasuya O. , Irawati P. , Yadav R. K. 
Published: November 2017

Abstract
We present the latest lunar occultation (LO) results obtained at the 2.4 m Thai National Telescope, continuing a program started in 2014. We report on 21 LO events for 20 stellar sources, yielding 7 binary stars, 1 angular diameter, and 1 star with extended circumstellar emission. These results, some of which are obtained for the first time, are discussed in the context of previous observations when available.
Polarized Transmission Spectrum of Earth as Observed during a Lunar Eclipse
Authors: Takahashi Jun , Itoh Yoichi , Hosoya Kensuke , Yanamandra-Fisher Padma A. , Hattori Takashi 
Published: November 2017

Abstract
Polarization during a lunar eclipse is a forgotten mystery. Coyne & Pellicori reported the detection of significant polarization during the lunar eclipse on 1968 April 13. Multiple scattering during the first transmission through Earth’s atmosphere was suggested as a possible cause of the polarization, but no conclusive determination was made. No further investigations on polarization during a lunar eclipse are known. We revisit this mystery with an interest in possible application to extrasolar planets; if planetary transmitted light is indeed polarized, it may be possible to investigate an exoplanet atmosphere using “transit polarimetry.” Here we report results of the first spectropolarimetry for the Moon during a lunar eclipse on 2015 April 4. We observed polarization degrees of 2%–3% at wavelengths of 500–600 nm; in addition, an enhanced feature was detected at the O2 A band near 760 nm. The observed time variation and wavelength dependence are consistent with an explanation of polarization caused by double scattering during the first transmission through Earth’s atmosphere, accompanied by latitudinal atmospheric inhomogeneity. Transit polarimetry for exoplanets may be useful to detect O2 gas and to probe the latitudinal atmospheric inhomogeneity, and it is thus worthy of serious consideration.
A Zone of Preferential Ion Heating Extends Tens of Solar Radii from the Sun
Authors: Kasper J. C. , Klein K. G. , Weber T. , Maksimovic M. , Zaslavsky A. , Bale S. D. , Maruca B. A. , Stevens M. L. , Case A. W. 
Published: November 2017

Abstract
The extreme temperatures and nonthermal nature of the solar corona and solar wind arise from an unidentified physical mechanism that preferentially heats certain ion species relative to others. Spectroscopic indicators of unequal temperatures commence within a fraction of a solar radius above the surface of the Sun, but the outer reach of this mechanism has yet to be determined. Here we present an empirical procedure for combining interplanetary solar wind measurements and a modeled energy equation including Coulomb relaxation to solve for the typical outer boundary of this zone of preferential heating. Applied to two decades of observations by the Wind spacecraft, our results are consistent with preferential heating being active in a zone extending from the transition region in the lower corona to an outer boundary 20–40 solar radii from the Sun, producing a steady-state super-mass-proportional α-to-proton temperature ratio of 5.2–5.3. Preferential ion heating continues far beyond the transition region and is important for the evolution of both the outer corona and the solar wind. The outer boundary of this zone is well below the orbits of spacecraft at 1 au and even closer missions such as Helios and MESSENGER, meaning it is likely that no existing mission has directly observed intense preferential heating, just residual signatures. We predict that the Parker Solar Probe will be the first spacecraft with a perihelion sufficiently close to the Sun to pass through the outer boundary, enter the zone of preferential heating, and directly observe the physical mechanism in action.
Molecular Gas in Debris Disks around Young A-type Stars
Authors: Moór Attila , Curé Michel , Kóspál Ágnes , Ábrahám Péter , Csengeri Timea , Eiroa Carlos , Gunawan Diah , Henning Thomas , Hughes A. Meredith , Juhász Attila , Pawellek Nicole , Wyatt Mark 
Published: November 2017

Abstract
According to the current paradigm of circumstellar disk evolution, gas-rich primordial disks evolve into gas-poor debris disks that are composed of second-generation dust. To explore the transition between these phases, we searched for 12CO, 13CO, and C18O emission in seven dust-rich debris disks around young A-type stars, using the Atacama Large Millimeter/submillimeter Array (ALMA) in Band 6. We discovered molecular gas in three debris disks. In all of these disks, the 12CO line was optically thick, highlighting the importance of less abundant molecules in reliable mass estimates. By supplementing our target list with literature data, we compiled a volume-limited sample of dust-rich debris disks around young A-type stars within 150 pc. We obtained a CO detection rate of 11/16 above a 12CO J = 2–1 line luminosity threshold of ∼1.4 × 104 Jy km s−1pc2 in the sample. This high incidence implies that the presence of CO gas in the bright debris disks around young A-type stars is more likely the rule than the exception. Interestingly, dust-rich debris disks around young FG-type stars exhibit, with the same detectability threshold as A-type stars, a significantly lower gas incidence. While the transition from the protoplanetary phase to the debris phase is associated with a drop in the dust content, our results exhibit a large spread in the CO mass in our debris sample, with peak values that are comparable to those in the protoplanetary Herbig Ae disks. In the particularly CO-rich debris systems, the gas may have a primordial origin, which is a characteristic of a hybrid disk.
Deuterium Fractionation upon the Formation of Hexamethylenetetramines through Photochemical Reactions of Interstellar Ice Analogs Containing Deuterated Methanol Isotopologues
Authors: Oba Yasuhiro , Takano Yoshinori , Naraoka Hiroshi , Kouchi Akira , Watanabe Naoki 
Published: November 2017

Abstract
Hexamethylenetetramine (HMT) is a representative product after the photolysis of interstellar ice analogs containing methanol followed by warming-up to room temperature. Since interstellar methanol is often significantly enriched in deuterium (D), the HMT photoproduct is expected to inherit D atoms from deuterated methanol. However, D fractionation upon the formation of HMT is not well understood, especially when it is produced from partly deuterated methanol isotopologues such as CH2DOH and CH3OD. Here, we experimentally studied the composition of deuterated HMT (d

n
-HMT, where n is the number of D atoms) at the isotopologue level formed by the photolysis of ice mixtures containing deuterated methanol, CH2DOH or CH3OD, at 10 or 77 K. The analyses were performed using a state-of-the-art high-resolution mass spectrometer coupled with a compound-specific separation technique. The formation of d

n
-HMT (n = 0–8) was confirmed under all experimental conditions. In addition, methyl- and hydroxyl-substituted HMT and their deuterated isotopologues were also obtained in the products. The deuterium enrichment was outstanding when CH2DOH was used rather than CH3OD, and when photolysis was performed at 77 K rather than 10 K. We found that the deuteration level of the formed HMT far exceeded that of the reactants under the present experimental conditions. These results obtained during stable isotope probing of deuterium strongly suggest that HMT can play a role as an organic pool of interstellar D atoms. These may be distributed into other chemical species through molecular evolution in space.
Long-term Spectral Variability of the Ultraluminous X-Ray Source Holmberg IX X–1
Authors: Jithesh V. , Misra Ranjeev , Wang Zhongxiang 
Published: November 2017

Abstract
We investigate the long-term spectral variability in the ultraluminous X-ray source Holmberg IX X–1. By analyzing the data from 8 Suzaku and 13 XMM-Newton observations conducted between 2001 and 2015, we perform a detailed spectral modeling for all spectra with simple models and complex physical models. We find that the spectra can be well explained by a disk-plus-thermal-Comptonization model. Applying this model, we unveil correlations between the X-ray luminosity (

L

X

) and the spectral parameters. One particular correlation is the statistically significant positive correlation between

L

X

and the photon index (Γ), while at the high luminosities of

>
2
×

10

40

erg

s

−
1

, the source becomes marginally hard, which results in a change in the slope of the

Γ
–

L

X

correlation. Similar variability behavior is observed in the optical depth of the source around

L

X

∼
2
×

10

40

erg

s

−
1

as the source becomes more optically thick. We consider the scenario that a corona covers the inner part of the disk, and the correlations can be explained as being driven by the variability of seed photons from the disk input into the corona. On the basis of the disk-corona model, we discuss the physical processes that are possibly indicated by the variability of the spectral parameters. Our analysis reveals the complex variability behavior of Holmberg IX X–1 and the variability mechanism is likely related to the geometry of the X-ray-emitting regions.
Detecting Binary Compact-object Mergers with Gravitational Waves: Understanding and Improving the Sensitivity of the PyCBC Search
Authors: Nitz Alexander H. , Dent Thomas , Dal Canton Tito , Fairhurst Stephen , Brown Duncan A. 
Published: November 2017

Abstract
We present an improved search for binary compact-object mergers using a network of ground-based gravitational-wave detectors. We model a volumetric, isotropic source population and incorporate the resulting distribution over signal amplitude, time delay, and coalescence phase into the ranking of candidate events. We describe an improved modeling of the background distribution, and demonstrate incorporating a prior model of the binary mass distribution in the ranking of candidate events. We find an

∼
10
%

and

∼
20
%

increase in detection volume for simulated binary neutron star and neutron star black hole systems, respectively, corresponding to a reduction of the false alarm rates assigned to signals by between one and two orders of magnitude.
The Intensity Modulation of the Fluorescent Line by a Finite Light Speed Effect in Accretion-powered X-Ray Pulsars
Authors: Yoshida Yuki , Kitamoto Shunji , Hoshino Akio 
Published: November 2017

Abstract
The X-ray line diagnostic method is a powerful tool for an investigation of plasma around accretion-powered X-ray pulsars. We point out an apparent intensity modulation of emission lines, with their rotation period of neutron stars, due to the finite speed of light (we call this effect the “finite light speed effect”) if the line emission mechanism is a kind of reprocessing, such as fluorescence or recombination after ionization by X-ray irradiation from pulsars. The modulation amplitude is determined by the size of the emission region, which is in competition with the smearing effect by the light crossing time in the emission region. This is efficient if the size of the emission region is roughly comparable to that of the rotation period multiplied by the speed of light. We apply this effect to a symbiotic X-ray pulsar, GX 1+4, where a spin modulation of the intense iron line of which has been reported. The finite light speed effect can explain the observed intensity modulation if its fluorescent region is the size of

∼

10

12

cm.
Widespread Presence of Glycolaldehyde and Ethylene Glycol around Sagittarius B2
Authors: Li Juan , Shen Zhiqiang , Wang Junzhi , Chen Xi , Li Di , Wu Yajun , Dong Jian , Zhao Rongbing , Gou Wei , Wang Jinqing , Li Shanghuo , Wang Bingru , Zheng Xingwu 
Published: November 2017

Abstract
We report the detection of widespread CH2OHCHO and HOCH2CH2OH emission in Galactic center giant molecular cloud Sagittarius B2 using the Shanghai Tianma 65 m Radio Telescope. Our observations show for the first time that the spatial distribution of these two important prebiotic molecules extends over 15 arcmin, corresponding to a linear size of approximately 36 pc. These two molecules are not just distributed in or near the hot cores. The abundance of these two molecules seems to decrease from the cold outer region to the central region associated with star formation activity. Results presented here suggest that these two molecules are likely to form through a low temperature process. Recent theoretical and experimental studies demonstrated that prebiotic molecules can be efficiently formed in icy grain mantles through several pathways. However, these complex ice features cannot be directly observed, and most constraints on the ice compositions come from millimeter observations of desorbed ice chemistry products. These results, combined with laboratory studies, strongly support the existence of abundant prebiotic molecules in ices.
The Impact of Progenitor Mass Loss on the Dynamical and Spectral Evolution of Supernova Remnants
Authors: Patnaude Daniel J. , Lee Shiu-Hang , Slane Patrick O. , Badenes Carles , Nagataki Shigehiro , Ellison Donald C. , Milisavljevic Dan 
Published: November 2017

Abstract
There is now substantial evidence that the progenitors of some core-collapse supernovae undergo enhanced or extreme mass loss prior to explosion. The imprint of this mass loss is observed in the spectra and dynamics of the expanding blast wave on timescales of days to years after core collapse, and the effects on the spectral and dynamical evolution may linger long after the supernova has evolved into the remnant stage. In this paper, we present, for the first time, largely self-consistent end-to-end simulations for the evolution of a massive star from the pre-main sequence, up to and through core collapse, and into the remnant phase. We present three models and compare and contrast how the progenitor mass-loss history impacts the dynamics and spectral evolution of the supernovae and supernova remnants. We study a model that only includes steady mass loss, a model with enhanced mass loss over a period of ∼5000 yr prior to core collapse, and a model with extreme mass loss over a period of ∼500 yr prior to core collapse. The models are not meant to address any particular supernova or supernova remnant, but rather to highlight the important role that the progenitor evolution plays in the observable qualities of supernovae and supernova remnants. Through comparisons of these three different progenitor evolution scenarios, we find that the mass loss in late stages (during and after core carbon burning) can have a profound impact on the dynamics and spectral evolution of the supernova remnant centuries after core collapse.
Connecting the Cosmic Star Formation Rate with the Local Star Formation
Authors: Gribel Carolina , Miranda Oswaldo D. , Vilas-Boas José Williams 
Published: November 2017

Abstract
We present a model that unifies the cosmic star formation rate (CSFR), obtained through the hierarchical structure formation scenario, with the (Galactic) local star formation rate (SFR). It is possible to use the SFR to generate a CSFR mapping through the density probability distribution functions commonly used to study the role of turbulence in the star-forming regions of the Galaxy. We obtain a consistent mapping from redshift

z
∼
20

up to the present (z = 0). Our results show that the turbulence exhibits a dual character, providing high values for the star formation efficiency (

〈
ε
〉
∼
0.32

) in the redshift interval

z
∼
3.5
–
20

and reducing its value to

〈
ε
〉
=
0.021

at z = 0. The value of the Mach number (



crit

), from which

〈
ε
〉

rapidly decreases, is dependent on both the polytropic index (Γ) and the minimum density contrast of the gas. We also derive Larson’s first law associated with the velocity dispersion (

〈

V

rms

〉

) in the local star formation regions. Our model shows good agreement with Larson’s law in the

∼
10
–
50

pc

range, providing typical temperatures

T

0

∼
10
–
80

K

for the gas associated with star formation. As a consequence, dark matter halos of great mass could contain a number of halos of much smaller mass, and be able to form structures similar to globular clusters. Thus, Larson’s law emerges as a result of the very formation of large-scale structures, which in turn would allow the formation of galactic systems, including our Galaxy.
The JCMT Transient Survey: Identifying Submillimeter Continuum Variability over Several Year Timescales Using Archival JCMT Gould Belt Survey Observations
Authors: Mairs Steve , Johnstone Doug , Kirk Helen , Lane James , Bell Graham S. , Graves Sarah , Herczeg Gregory J. , Scicluna Peter , Bower Geoffrey C. , Chen Huei-Ru Vivien , Hatchell Jennifer , Aikawa Yuri , Chen Wen-Ping , Kang Miju , Kang Sung-Ju , Lee Jeong-Eun , Morata Oscar , Pon Andy , Scholz Aleks , Takahashi Satoko , Yoo Hyunju ,   (The JCMT Transient Team)
Published: November 2017

Abstract
Investigating variability at the earliest stages of low-mass star formation is fundamental in understanding how a protostar assembles mass. While many simulations of protostellar disks predict non-steady accretion onto protostars, deeper investigation requires robust observational constraints on the frequency and amplitude of variability events characterized across the observable SED. In this study, we develop methods to robustly analyze repeated observations of an area of the sky for submillimeter variability in order to determine constraints on the magnitude and frequency of deeply embedded protostars. We compare 850 μm JCMT Transient Survey data with archival JCMT Gould Belt Survey data to investigate variability over 2–4 year timescales. Out of 175 bright, independent emission sources identified in the overlapping fields, we find seven variable candidates, five of which we classify as Strong, and the remaining two we classify as Extended to indicate that the latter are associated with larger-scale structure. For the Strong variable candidates, we find an average fractional peak brightness change per year of

∣
4.0
∣
%

yr

−
1

, with a standard deviation of

2.7
%

yr

−
1

. In total, 7% of the protostars associated with 850 μm emission in our sample show signs of variability. Four of the five Strong sources are associated with a known protostar. The remaining source is a good follow-up target for an object that is anticipated to contain an enshrouded, deeply embedded protostar. In addition, we estimate the 850 μm periodicity of the submillimeter variable source, EC 53, to be 567 ± 32 days, based on the archival Gould Belt Survey data.
Chapitre 2. Utilisation des Big Data en santé : le cas des objets connectés
Authors: Brouard Benoît 
Published: November 2017

Selon le rapport « The Internet of Things Market », le nombre d’objets connectés devrait être de 68 milliards en 2020. De plus, en 2012, le total des données stockées dans le monde était de 500 petabytes. Après la course à la puissance de calcul puis au développement des réseaux, l’enjeu réside désormais dans le stockage de ces données dans le « cloud », mais aussi et surtout, à libérer leur accès (open data) et à les traiter rapidement et en masse (Big Data). L’utilisation de ces données à bon escient est un enjeu majeur pour la recherche et la santé publique.
Chapitre 7. Big data ou l’illusion d’une synthèse par agrégation. Une critique épistémologique, éthique et politique
Authors: Coutellec Léo , Weil-Dubuc Paul-Loup 
Published: November 2017

Dans cet article, nous proposons une approche critique du phénomène big data par la déconstruction du principe méthodologique qui en structure la logique : le principe d’agrégation. Notre hypothèse se situe en amont des critiques qui font de l’usage des big data un nouveau mode de gouvernement. L’agrégation, comme mode de traitement de l’hétérogénéité des données, structure la pensée big data , elle en est la logique même. Fragmenter pour mieux agréger, agréger pour mieux fragmenter, une dialectique qui repose sur une présomption d’agrégabilité généralisée et sur la prétention de faire de l’agrégation la voie privilégiée pour la production de nouvelles synthèses. Nous procédons en trois temps pour déconstruire cette idée et défaire la prétention de l’agrégation à s’imposer comme nouvelle voie pour produire des connaissances, comme nouvelle synthèse identitaire et enfin comme nouveau modèle de solidarité. Chaque fois nous montrerons que ces tentatives d’agrégation échouent à produire leurs objets : ni connaissance, ni identité, ni solidarité ne peuvent résulter d’un processus d’amalgame. Dans les trois cas, l’agrégation s’accompagne toujours d’un moment de fragmentation dont la dissociation, la dislocation et la séparation sont différentes figures. Le pari que nous faisons alors est de faire hésiter ce qui se présente comme une nouvelle façon de penser l’homme et le monde.
Le pouvoir des formatages à l’heure de la balconisation
Authors: Dullaart Constant , Chazel Quentin , Roman Killian 
Published: November 2017

Cet entretien permet à Constant Dullaart de préciser sa définition de la « balconisation » et de commenter son intervention sur les logiciels de Facebook et d’Instagram ainsi que dans les racines idéologiques du logiciel Photoshop (à travers son œuvre Jennifer in Paradise ). Comment des pratiques indissociablement artistiques et activistes peuvent-elles court-circuiter ce qui court-circuite nos attentions ?