bluuebunny/crossref_metadata_2025_split huggingface dataset:
Possible Outcomes of Coplanar High-eccentricity Migration: Hot Jupiters, Close-in Super-Earths, and Counter-orbiting Planets
Authors: Xue Yuxin , Masuda Kento , Suto Yasushi 
Published: January 2017

Abstract
We investigate the formation of close-in planets in near-coplanar eccentric hierarchical triple systems via the secular interaction between an inner planet and an outer perturber (Coplanar High-eccentricity Migration; CHEM). We generalize the previous work on the analytical condition for successful CHEM for point masses interacting only through gravity by taking into account the finite mass effect of the inner planet. We find that efficient CHEM requires that the systems should have m
1 ≪ m
0 and m
1 ≪ m
2. In addition to the gravity for point masses, we examine the importance of the short-range forces, and provide an analytical estimate of the migration timescale. We perform a series of numerical simulations in CHEM for systems consisting of a Sun-like central star, giant gas inner planet, and planetary outer perturber, including the short-range forces and stellar and planetary dissipative tides. We find that most of such systems end up with a tidal disruption; a small fraction of the systems produce prograde hot Jupiters (HJs), but no retrograde HJ. In addition, we extend CHEM to super-Earth mass range, and show that the formation of close-in super-Earths in prograde orbits is also possible. Finally, we carry out CHEM simulation for the observed hierarchical triple and counter-orbiting HJ systems. We find that CHEM can explain a part of the former systems, but it is generally very difficult to reproduce counter-orbiting HJ systems.
Early GRB Afterglows from Reverse Shocks in Ultra-relativistic, Long-lasting Winds
Authors: Lyutikov Maxim , Jaramillo Juan Camilo 
Published: January 2017

Abstract
We develop a model of early Gamma-Ray Burst (GRB) afterglows with dominant X-ray contribution from the reverse shock (RS) propagating in highly relativistic (Lorentz factor γ

w
∼ 106) magnetized wind of a long-lasting central engine. The model reproduces, in a fairly natural way, the overall trends and yet allows for variations in the temporal and spectral evolution of early optical and X-ray afterglows. The high energy and the optical synchrotron emission from the RS particles occurs in the fast cooling regime; the resulting synchrotron power L

s
is a large fraction of the wind luminosity,

(L

w
and σ

w
are wind power and magnetization). Thus, plateaus—parts of afterglow light curves that show slowly decreasing spectral power—are a natural consequence of the RS emission. Contribution from the forward shock (FS) is negligible in the X-rays, but in the optical both FS and RS contribute similarly: FS optical emission is in the slow cooling regime, producing smooth components, while RS optical emission is in the fast cooling regime, and thus can both produce optical plateaus and account for fast optical variability correlated with the X-rays, e.g., due to changes in the wind properties. We discuss how the RS emission in the X-rays and combined FS and RS emission in the optical can explain many puzzling properties of early GRB afterglows.
Giant Lyα Nebulae in the Illustris Simulation
Authors: Gronke Max , Bird Simeon 
Published: January 2017

Abstract
Several “giant” Lyα nebulae with an extent ≳300 kpc and observed Lyα luminosity of ≳1044 erg s−1 cm−2 arcsec−2 have recently been detected, and it has been speculated that their presence hints at a substantial cold gas reservoir in small cool clumps not resolved in modern hydrodynamical simulations. We use the Illustris simulation to predict the Lyα emission emerging from large halos (M > 1011.5
M
⊙) at z ∼ 2 and thus test this model. We consider both active galactic nucleus (AGN) and star driven ionization, and compare the simulated surface brightness maps, profiles, and Lyα spectra to a model where most gas is clumped below the simulation resolution scale. We find that with Illustris, no additional clumping is necessary to explain the extents, luminosities, and surface brightness profiles of the “giant Lyα nebulae” observed. Furthermore, the maximal extents of the objects show a wide spread for a given luminosity and do not correlate significantly with any halo properties. We also show how the detected size depends strongly on the employed surface brightness cutoff, and predict that further examples of such objects will be found in the near future.
A Black Hole Mass Determination for the Compact Galaxy Mrk 1216
Authors: Walsh Jonelle L. , van den Bosch Remco C. E. , Gebhardt Karl , Yıldırım Akın , Gültekin Kayhan , Husemann Bernd , Richstone Douglas O. 
Published: January 2017

Abstract
Mrk 1216 is a nearby, early-type galaxy with a small effective radius of 2.8 kpc and a large stellar velocity dispersion of 308 km s−1 for its K-band luminosity of

. Using integral field spectroscopy assisted by adaptive optics from Gemini North, we measure spatially resolved stellar kinematics within ∼450 pc of the galaxy nucleus. The galaxy exhibits regular rotation with velocities of ±180 km s−1 and a sharply peaked velocity dispersion profile that reaches 425 km s−1 at the center. We fit axisymmetric, orbit-based dynamical models to the combination of these high angular resolution kinematics, large-scale kinematics extending to roughly three effective radii, and Hubble Space Telescope imaging, resulting in a constraint of the mass of the central black hole in Mrk 1216. After exploring several possible sources of systematics that commonly affect stellar-dynamical black hole mass measurements, we find a black hole mass of

and an H-band stellar mass-to-light ratio of

(1σ uncertainties). Mrk 1216 is consistent with the local black hole mass–stellar velocity dispersion relation, but is a factor of ∼5–10 larger than expectations from the black hole mass–bulge luminosity and black hole mass–bulge mass correlations when conservatively using the galaxy’s total luminosity or stellar mass. This behavior is quite similar to the extensively studied compact galaxy NGC 1277. Resembling the

quiescent galaxies, Mrk 1216 may be a passively evolved descendant, and perhaps reflects a previous era when galaxies contained over-massive black holes relative to their bulge luminosities/masses, and the growth of host galaxies had yet to catch up.
The Orbital Nature of 81 Ellipsoidal Red Giant Binaries in the Large Magellanic Cloud
Authors: Nie J. D. , Wood P. R. , Nicholls C. P. 
Published: January 2017

Abstract
In this paper, we collect a sample of 81 ellipsoidal red giant binaries in the Large Magellanic Cloud (LMC), and we study their orbital natures individually and statistically. The sample contains 59 systems with circular orbits and 22 systems with eccentric orbits. We derive orbital solutions using the 2010 version of the Wilson–Devinney code. The sample is selection-bias corrected, and the orbital parameter distributions are compared to model predictions for the LMC and to observations in the solar vicinity. The masses of the red giant primaries are found to range from about 0.6 to 9

with a peak at around 1.5

, in agreement with studies of the star formation history of the LMC, which find a burst of star formation beginning around 4 Gyr ago. The observed distribution of mass ratios

is more consistent with the flat q distribution derived for the solar vicinity by Raghavan et al. than it is with the solar vicinity q distribution derived by Duquennoy & Mayor. There is no evidence for an excess number of systems with equal mass components. We find that about 20% of the ellipsoidal binaries have eccentric orbits, twice the fraction estimated by Soszynski et al. Our eccentricity evolution test shows that the existence of eccentric ellipsoidal red giant binaries on the upper parts of the red giant branch (RGB) can only be explained if tidal circularization rates are ∼1/100 the rates given by the usual theory of tidal dissipation in convective stars.
Polarization Gradient Study of Interstellar Medium Turbulence Using the Canadian Galactic Plane Survey
Authors: Herron C. A. , Geisbuesch J. , Landecker T. L. , Kothes R. , Gaensler B. M. , Lewis G. F. , McClure-Griffiths N. M. , Petroff E. 
Published: January 2017

Abstract
We have investigated the magneto-ionic turbulence in the interstellar medium through spatial gradients of the complex radio polarization vector in the Canadian Galactic Plane Survey (CGPS). The CGPS data cover 1300 square degrees, over the range

,

, with an extension to

in the range

, and arcminute resolution at 1420 MHz. Previous studies found a correlation between the skewness and kurtosis of the polarization gradient and the Mach number of the turbulence, or assumed this correlation to deduce the Mach number of an observed turbulent region. We present polarization gradient images of the entire CGPS data set, and analyze the dependence of these images on angular resolution. The polarization gradients are filamentary, and the length of these filaments is largest toward the Galactic anti-center, with the smallest toward the inner Galaxy. This may imply that small-scale turbulence is stronger in the inner Galaxy, or that we observe more distant features at low Galactic longitudes. For every resolution studied, the skewness of the polarization gradient is influenced by the edges of bright polarization gradient regions, which are not related to the turbulence revealed by the polarization gradients. We also find that the skewness of the polarization gradient is sensitive to the size of the box used to calculate the skewness, but insensitive to Galactic longitude, implying that the skewness only probes the number and magnitude of the inhomogeneities within the box. We conclude that the skewness and kurtosis of the polarization gradient are not ideal statistics for probing natural magneto-ionic turbulence.
Observations of Lyα and O vi: Signatures of Cooling and Star Formation in a Massive Central Cluster Galaxy
Authors: Donahue Megan , Connor Thomas , Voit G. Mark , Postman Marc 
Published: January 2017

Abstract
We report new Hubble Space Telescope COS and Space Telescope Imaging Spectrograph spectroscopy of a star-forming region (

yr−1) in the center of the X-ray cluster RX J1532.9+3021 (z = 0.362), to follow-up the CLASH team discovery of luminous UV filaments and knots in the central massive galaxy. We detect broad (∼500 km s−1) Lyα emission lines with extraordinarily high equivalent widths (EQW ∼ 200 Å) and somewhat less broadened Hα (∼220 km s−1). Ultraviolet emission lines of N v and O vi are not detected, which constrains the rate at which gas cools through temperatures of 106 K to be ≲10 M
⊙ yr−1. The COS spectra also show a flat rest-frame UV continuum with weak stellar photospheric features, consistent with the presence of recently formed hot stars forming at a rate of ∼10 M
⊙ yr−1, uncorrected for dust extinction. The slope and absorption lines in these UV spectra are similar to those of Lyman Break Galaxies at

, albeit those with the highest Lyα equivalent widths and star formation rates. This high-EQW Lyα source is a high-metallicity galaxy rapidly forming stars in structures that look nothing like disks. This mode of star formation could significantly contribute to the spheroidal population of galaxies. The constraint on the luminosity of any O vi line emission is stringent enough to rule out steady and simultaneous gas cooling and star formation, unlike similar systems in the Phoenix Cluster and Abell 1795. The fact that the current star formation rate differs from the local mass cooling rate is consistent with recent simulations of episodic active galactic nucleus feedback and star formation in a cluster atmosphere.
Millimeter-wave Line Ratios and Sub-beam Volume Density Distributions
Authors: Leroy Adam K. , Usero Antonio , Schruba Andreas , Bigiel Frank , Kruijssen J. M. Diederik , Kepley Amanda , Blanc Guillermo A. , Bolatto Alberto D. , Cormier Diane , Gallagher Molly , Hughes Annie , Jiménez-Donaire Maria J. , Rosolowsky Erik , Schinnerer Eva 
Published: January 2017

Abstract
We explore the use of mm-wave emission line ratios to trace molecular gas density when observations integrate over a wide range of volume densities within a single telescope beam. For observations targeting external galaxies, this case is unavoidable. Using a framework similar to that of Krumholz & Thompson, we model emission for a set of common extragalactic lines from lognormal and power law density distributions. We consider the median density of gas that produces emission and the ability to predict density variations from observed line ratios. We emphasize line ratio variations because these do not require us to know the absolute abundance of our tracers. Patterns of line ratio variations have the potential to illuminate the high-end shape of the density distribution, and to capture changes in the dense gas fraction and median volume density. Our results with and without a high-density power law tail differ appreciably; we highlight better knowledge of the probability density function (PDF) shape as an important area. We also show the implications of sub-beam density distributions for isotopologue studies targeting dense gas tracers. Differential excitation often implies a significant correction to the naive case. We provide tabulated versions of many of our results, which can be used to interpret changes in mm-wave line ratios in terms of adjustments to the underlying density distributions.
A Candidate for an Intrinsic Dusty Absorber with a Metal-rich Damped Lyα Absorption Line System in the Quasar J170542.91+354340.2
Authors: Pan Xiang , Zhou Hongyan , Ge Jian , Jiang Peng , Yang Bin , Lu Honglin , Ji Tuo , Zhang Shaohua , Shi Xiheng 
Published: January 2017

Abstract
We present a detailed analysis of the unusual damped Lyα absorption line system (DLA) toward the quasar SDSS J170542.91+354340.2 at a redshift of 2, previously reported by Noterdaeme et al. as one of the very few CO absorbers known to date at high z. This DLA is exceptional in that: (1) its extinction curve is similar to peculiar Milky Way sightlines penetrating star formation regions; (2) its absorption components are redshifted at a speed of several hundred km s−1 compared to broad Balmer emission lines; (3) its gas-phase metallicity is super-solar as evaluated from more than 30 absorption lines; (4) detection of residual flux in the DLA trough and variability of

absorption is possible. Based on these facts, we argue that this dusty DLA is a good candidate for an intrinsic quasar 2175 Å absorber, and can originate from star formation regions of the quasar’s host galaxy. We discuss in detail the gas and dust properties, and the dust depletion. Follow-up observations, such as spectropolarimetry and optical/infrared spectroscopy, will help to confirm the system’s intrinsic nature and to explore how dust grains behave in the extreme environments proximate to quasars.
Fermi-LAT Observations of High-energy Behind-the-limb Solar Flares
Authors: Ackermann M. , Allafort A. , Baldini L. , Barbiellini G. , Bastieri D. , Bellazzini R. , Bissaldi E. , Bonino R. , Bottacini E. , Bregeon J. , Bruel P. , Buehler R. , Cameron R. A. , Caragiulo M. , Caraveo P. A. , Cavazzuti E. , Cecchi C. , Charles E. , Ciprini S. , Costanza F. , Cutini S. , D’Ammando F. , Palma F. de , Desiante R. , Digel S. W. , Lalla N. Di , Mauro M. Di , Venere L. Di , Drell P. S. , Favuzzi C. , Fukazawa Y. , Fusco P. , Gargano F. , Giglietto N. , Giordano F. , Giroletti M. , Grenier I. A. , Guillemot L. , Guiriec S. , Jogler T. , Jóhannesson G. , Kashapova L. , Krucker S. , Kuss M. , Mura G. La , Larsson S. , Latronico L. , Li J. , Liu W. , Longo F. , Loparco F. , Lubrano P. , Magill J. D. , Maldera S. , Manfreda A. , Mazziotta M. N. , Mitthumsiri W. , Mizuno T. , Monzani M. E. , Morselli A. , Moskalenko I. V. , Negro M. , Nuss E. , Ohsugi T. , Omodei N. , Orlando E. , Pal’shin V. , Paneque D. , Perkins J. S. , Pesce-Rollins M. , Petrosian V. , Piron F. , Principe G. , Rainò S. , Rando R. , Razzano M. , Reimer O. , Costa F. Rubio da , Sgrò C. , Simone D. , Siskind E. J. , Spada F. , Spandre G. , Spinelli P. , Tajima H. , Thayer J. B. , Torres D. F. , Troja E. , Vianello G. 
Published: January 2017

Abstract
We report on the Fermi-LAT detection of high-energy emission from the behind-the-limb (BTL) solar flares that occurred on 2013 October 11, and 2014 January 6 and September 1. The Fermi-LAT observations are associated with flares from active regions originating behind both the eastern and western limbs, as determined by STEREO. All three flares are associated with very fast coronal mass ejections (CMEs) and strong solar energetic particle events. We present updated localizations of the >100 MeV photon emission, hard X-ray (HXR) and EUV images, and broadband spectra from 10 keV to 10 GeV, as well as microwave spectra. We also provide a comparison of the BTL flares detected by Fermi-LAT with three on-disk flares and present a study of some of the significant quantities of these flares as an attempt to better understand the acceleration mechanisms at work during these occulted flares. We interpret the HXR emission to be due to electron bremsstrahlung from a coronal thin-target loop top with the accelerated electron spectra steepening at semirelativistic energies. The >100 MeV gamma-rays are best described by a pion-decay model resulting from the interaction of protons (and other ions) in a thick-target photospheric source. The protons are believed to have been accelerated (to energies >10 GeV) in the CME environment and precipitate down to the photosphere from the downstream side of the CME shock and landed on the front side of the Sun, away from the original flare site and the HXR emission.
AGN Coronae through a Jet Perspective
Authors: King Ashley L. , Lohfink Anne , Kara Erin 
Published: January 2017

Abstract
This paper presents an in-depth look at the jet and coronal properties of 41 active galactic nuclei (AGNs). Utilizing the highest quality NuSTAR, XMM-Newton, and NRAO VLA Sky Survey 1.4 GHz data, we find that the radio Eddington luminosity inversely scales with X-ray reflection fraction, and positively scales with the distance between the corona and the reflected regions in the disk. We next investigate a model fit to the data that predicts the corona is outflowing and propagates into the large-scale jet. We find this model describes the data well and predicts that the corona has mildly relativistic velocities,

. We discuss our results in the context of disk–jet connections in AGNs.
Growth of a Massive Young Stellar Object Fed by a Gas Flow from a Companion Gas Clump
Authors: Chen Xi , Ren Zhiyuan , Zhang Qizhou , Shen Zhiqiang , Qiu Keping 
Published: January 2017

Abstract
We present a Submillimeter Array (SMA) observation toward the young massive double-core system G350.69-0.49. This system consists of a northeast (NE) diffuse gas bubble and a southwest (SW) massive young stellar object (MYSO), both clearly seen in the Spitzer images. The SMA observations reveal a gas flow between the NE bubble and the SW MYSO in a broad velocity range from 5 to 30 km s−1 with respect to the system velocity. The gas flow is well confined within the interval between the two objects and traces a significant mass transfer from the NE gas bubble to the SW massive core. The transfer flow can supply the material accreted onto the SW MYSO at a rate of 4.2 × 10−4 M
⊙ yr−1. The whole system therefore suggests a mode for the mass growth in the MYSO from a gas transfer flow launched from its companion gas clump, despite the driving mechanism of the transfer flow not being fully determined from the current data.
Anomalous Galactic Cosmic Rays in the Framework of AMS-02
Authors: Khiali Behrouz , Haino Sadakazu , Feng Jie 
Published: January 2017

Abstract
The cosmic-ray (CR) energy spectra of protons and helium nuclei, which are the most abundant components of cosmic radiation, exhibit a remarkable hardening at energies above 100 GeV/nucleon. Recent data from AMS-02 confirm this feature with a higher significance. These data challenge the current models of CR acceleration in Galactic sources and propagation in the Galaxy. Here, we explain the observed break in the spectra of protons and helium nuclei in light of recent advances in CR diffusion theories in turbulent astrophysical sources as being a result of a transition between different CR diffusion regimes. We reconstruct the observed CR spectra using the fact that a transition from normal diffusion to superdiffusion changes the efficiency of particle acceleration and causes the change in the spectral index. We find that calculated proton and helium spectra match the data very well.
3D Radiation Nonideal Magnetohydrodynamical Simulations of the Inner Rim in Protoplanetary Disks
Authors: Flock M. , Fromang S. , Turner N. J. , Benisty M. 
Published: January 2017

Abstract
Many planets orbit within 1 au of their stars, raising questions about their origins. Particularly puzzling are the planets found near the silicate sublimation front. We investigate conditions near the front in the protostellar disk around a young intermediate-mass star, using the first global 3D radiation nonideal MHD simulations in this context. We treat the starlight heating; the silicate grains’ sublimation and deposition at the local, time-varying temperature and density; temperature-dependent ohmic dissipation; and various initial magnetic fields. The results show magnetorotational turbulence around the sublimation front at 0.5 au. The disk interior to 0.8 au is turbulent, with velocities exceeding 10% of the sound speed. Beyond 0.8 au is the dead zone, cooler than 1000 K and with turbulence orders of magnitude weaker. A local pressure maximum just inside the dead zone concentrates solid particles, favoring their growth. Over many orbits, a vortex develops at the dead zone’s inner edge, increasing the disk’s thickness locally by around 10%. We synthetically observe the results using Monte Carlo transfer calculations, finding that the sublimation front is near-infrared bright. The models with net vertical magnetic fields develop extended, magnetically supported atmospheres that reprocess extra starlight, raising the near-infrared flux 20%. The vortex throws a nonaxisymmetric shadow on the outer disk. At wavelengths

, the flux varies several percent on monthly timescales. The variations are more regular when the vortex is present. The vortex is directly visible as an arc at ultraviolet through near-infrared wavelengths, given sub-au spatial resolution.
Metal-silicate Partitioning and Its Role in Core Formation and Composition on Super-Earths
Authors: Schaefer Laura , B. Jacobsen Stein , Remo John L. , Petaev M. I. , Sasselov Dimitar D. 
Published: January 2017

Abstract
We use a thermodynamic framework for silicate-metal partitioning to determine the possible compositions of metallic cores on super-Earths. We compare results using literature values of the partition coefficients of Si and Ni, as well as new partition coefficients calculated using results from laser shock-induced melting of powdered metal-dunite targets at pressures up to 276 GPa, which approaches those found within the deep mantles of super-Earths. We find that larger planets may have little to no light elements in their cores because the Si partition coefficient decreases at high pressures. The planet mass at which this occurs will depend on the metal-silicate equilibration depth. We also extrapolate the equations of state (EOS) of FeO and FeSi alloys to high pressures, and present mass–radius diagrams using self-consistent planet compositions assuming equilibrated mantles and cores. We confirm the results of previous studies that the distribution of elements between mantle and core will not be detectable from mass and radius measurements alone. While observations may be insensitive to interior structure, further modeling is sensitive to compositionally dependent properties, such as mantle viscosity and core freeze-out properties. We therefore emphasize the need for additional high pressure measurements of partitioning as well as EOSs, and highlight the utility of the Sandia Z-facilities for this type of work.