bluuebunny/crossref_metadata_2025_split huggingface dataset:
NuSTAR OBSERVATIONS OF WISE J1036+0449, A GALAXY AT z ∼ 1 OBSCURED BY HOT DUST
Authors: Ricci C. , Assef R. J. , Stern D. , Nikutta R. , Alexander D. M. , Asmus D. , Ballantyne D. R. , Bauer F. E. , Blain A. W. , Boggs S. , Boorman P. G. , Brandt W. N. , Brightman M. , Chang C. S. , Chen C.-T. J. , Christensen F. E. , Comastri A. , Craig W. W. , Díaz-Santos T. , Eisenhardt P. R. , Farrah D. , Gandhi P. , Hailey C. J. , Harrison F. A. , Jun H. D. , Koss M. J. , LaMassa S. , Lansbury G. B. , Markwardt C. B. , Stalevski M. , Stanley F. , Treister E. , Tsai C.-W. , Walton D. J. , Wu J. W. , Zappacosta L. , Zhang W. W. 
Published: January 2017

ABSTRACT
Hot dust-obscured galaxies (hot DOGs), selected from Wide-Field Infrared Survey Explorer’s all-sky infrared survey, host some of the most powerful active galactic nuclei known and may represent an important stage in the evolution of galaxies. Most known hot DOGs are located at

, due in part to a strong bias against identifying them at lower redshift related to the selection criteria. We present a new selection method that identifies 153 hot DOG candidates at

, where they are significantly brighter and easier to study. We validate this approach by measuring a redshift z = 1.009 and finding a spectral energy distribution similar to that of higher-redshift hot DOGs for one of these objects, WISE J1036+0449 (

). We find evidence of a broadened component in Mg ii, which would imply a black hole mass of

and an Eddington ratio of

. WISE J1036+0449 is the first hot DOG detected by the Nuclear Spectroscopic Telescope Array, and observations show that the source is heavily obscured, with a column density of

. The source has an intrinsic 2–10 keV luminosity of

, a value significantly lower than that expected from the mid-infrared/X-ray correlation. We also find that other hot DOGs observed by X-ray facilities show a similar deficiency of X-ray flux. We discuss the origin of the X-ray weakness and the absorption properties of hot DOGs. Hot DOGs at

could be excellent laboratories to probe the characteristics of the accretion flow and of the X-ray emitting plasma at extreme values of the Eddington ratio.
HERSCHEL EXTREME LENSING LINE OBSERVATIONS: [C ii] VARIATIONS IN GALAXIES AT REDSHIFTS z = 1–3*
Authors: Malhotra Sangeeta , Rhoads James E. , Finkelstein K. , Yang Huan , Carilli Chris , Combes Françoise , Dassas Karine , Finkelstein Steven , Frye Brenda , Gerin Maryvonne , Guillard Pierre , Nesvadba Nicole , Rigby Jane , Shin Min-Su , Spaans Marco , Strauss Michael A. , Papovich Casey 
Published: January 2017

ABSTRACT
We observed the [C ii] line in 15 lensed galaxies at redshifts 1 < z < 3 using HIFI on the Herschel Space Observatory and detected 14/15 galaxies at 3σ or better. High magnifications enable even modestly luminous galaxies to be detected in [C ii] with Herschel. The [C ii] luminosity in this sample ranges from 8 × 107
L
⊙ to 3.7 × 109
L
⊙ (after correcting for magnification), confirming that [C ii] is a strong tracer of the ISM at high redshifts. The ratio of the [C ii] line to the total far-infrared (FIR) luminosity serves as a measure of the ratio of gas to dust cooling and thus the efficiency of the grain photoelectric heating process. It varies between 3.3% and 0.09%. We compare the [C ii]/FIR ratio to that of galaxies at z = 0 and at high redshifts and find that they follow similar trends. The [C ii]/FIR ratio is lower for galaxies with higher dust temperatures. This is best explained if increased UV intensity leads to higher FIR luminosity and dust temperatures, but gas heating does not rise due to lower photoelectric heating efficiency. The [C ii]/FIR ratio shows weaker correlation with FIR luminosity. At low redshifts highly luminous galaxies tend to have warm dust, so the effects of dust temperature and luminosity are degenerate. Luminous galaxies at high redshifts show a range of dust temperatures, showing that [C ii]/FIR correlates most strongly with dust temperature. The [C ii] to mid-IR ratio for the HELLO sample is similar to the values seen for low-redshift galaxies, indicating that small grains and PAHs dominate the heating in the neutral ISM, although some of the high [CII]/FIR ratios may be due to turbulent heating.
DYNAMIC DEUTERIUM ENRICHMENT IN COMETARY WATER VIA ELEY–RIDEAL REACTIONS
Authors: Yao Yunxi , Giapis Konstantinos P. 
Published: January 2017

ABSTRACT
The deuterium-to-hydrogen ratio (D/H) in water found in the coma of Jupiter family comet (JFC) 67P/Churyumov–Gerasimenko was reported to be (5.3 ± 0.7) × 10−4, the highest among comets and three times the value for other JFCs with an ocean-like ratio. This discrepancy suggests the diverse origins of JFCs and clouds the issue of the origin of Earth’s oceanic water. Here we demonstrate that Eley–Rideal reactions between accelerated water ions and deuterated cometary surface analogs can lead to instantaneous deuterium enrichment in water scattered from the surface. The reaction proceeds with H2O+ abstracting adsorbed D atoms, forming an excited H2DO* state, which dissociates subsequently to produce energetic HDO. Hydronium ions are also produced readily by the abstraction of H atoms, consistent with H3O+ detection and abundance in various comets. Experiments with water isotopologs and kinematic analysis on deuterated platinum surfaces confirmed the dynamic abstraction mechanism. The instantaneous fractionation process is independent of the surface temperature and may operate on the surface of cometary nuclei or dust grains, composed of deuterium-rich silicates and carbonaceous chondrites. The requisite energetic water ions have been detected in the coma of 67P in two populations. This dynamic fractionation process may temporarily increase the water D/H ratio, especially as the comet gets closer to the Sun. The magnitude of the effect depends on the water ion energy-flux and the deuterium content of the exposed cometary surfaces.
DRAINING THE LOCAL VOID
Authors: Rizzi Luca , Tully R. Brent , Shaya Edward J. , Kourkchi Ehsan , Karachentsev Igor D. 
Published: January 2017

ABSTRACT
Two galaxies that lie deep within the Local Void provide a test of the expectation that voids expand. The modest (

M

B

∼
−
14

) HI bearing dwarf galaxies ALFAZOAJ1952+1428 and KK246 have been imaged with Hubble Space Telescope in order to study the stellar populations and determine distances from the luminosities of stars at the tip of the red giant branch. The mixed age systems have respective distances of 8.39 Mpc and 6.95 Mpc and inferred line-of-sight peculiar velocities of −114 km s−1 and −66 km s−1 toward us and away from the void center. These motions compound on the Milky Way motion of ∼230 km s−1 away from the void. The orbits of the two galaxies are reasonably constrained by a numerical action model encompassing an extensive region that embraces the Local Void. It is unambiguously confirmed that these two void galaxies are moving away from the void center at several hundred km s−1.
NEW DETECTIONS OF HNC IN PLANETARY NEBULAE: EVOLUTION OF THE [HCN]/[HNC] RATIO
Authors: Schmidt D. R. , Ziurys L. M. 
Published: January 2017

ABSTRACT
New detections of HNC have been made toward 11 planetary nebulae (PNe), including K4-47, K3-58, K3-17, M3-28, and M4-14. These sources, which represent a wide range of ages and morphologies, had previously been observed in HCN by Schmidt & Ziurys. Measurements of the

J
=
1
→
0

and

J
=
3
→
2

transitions of HNC near 90 and 271 GHz were conducted using the new 12 m and the Sub-Millimeter Telescope of the Arizona Radio Observatory. HCN and HNC were also identified via their

J
=
1
→
0

lines toward eight positions across the Helix Nebula (NGC 7293). Column densities for HNC, determined from radiative transfer modeling, were N
tot(HNC) ∼ (0.06–4.0) × 1013 cm−2, corresponding to fractional abundances with respect to H2 of f ∼ (0.02–1.4) × 10−7. The HCN and HNC column densities across the Helix were found to be

N

tot

(
HCN
)

∼ (0.2–2.4) × 1012 cm−2 and

N

tot

(
HNC
)

∼ (0.07–1.6) × 1012 cm−2, with fractional abundances of (0.2–3.2) × 10−7 and (0.09–2.2) × 10−7. The [HCN]/[HNC] ratio varied between ∼1–8 for all PNe, with [HCN]/[HNC] ∼1–4 across the Helix. These values are greatly reduced from what has been found in asymptotic giant branch stars, where the ratio is typically >100. Both the abundance of HNC and the [HCN]/[HNC] ratio do not appear to vary significantly with nebular age across a time span of ∼10,000 years, in contrast to predictions of chemical models. The increase in HNC appears to arise in the proto-planetary stage, but becomes “frozen” once the PN phase is reached.
BRIGHT METAL-POOR STARS FROM THE HAMBURG/ESO SURVEY. II. A CHEMODYNAMICAL ANALYSIS
Authors: Beers Timothy C. , Placco Vinicius M. , Carollo Daniela , Rossi Silvia , Lee Young Sun , Frebel Anna , Norris John E. , Dietz Sarah , Masseron Thomas 
Published: January 2017

ABSTRACT
We obtain estimates of stellar atmospheric parameters for a previously published sample of 1777 relatively bright (

9
<
B
<
14

) metal-poor candidates from the Hamburg/ESO Survey. The original Frebel et al. analysis of these stars was able to derive estimates of [Fe/H] and [C/Fe] only for a subset of the sample, due to limitations in the methodology then available. A new spectroscopic analysis pipeline has been used to obtain estimates of

T

eff

,

log

g

, [Fe/H], and [C/Fe] for almost the entire data set. This sample is very local—about 90% of the stars are located within 0.5 kpc of the Sun. We consider the chemodynamical properties of these stars in concert with a similarly local sample of stars from a recent analysis of the Bidelman and MacConnell “weak metal” candidates by Beers et al. We use this combined sample to identify possible members of the halo stream of stars suggested by Helmi et al. and Chiba & Beers, as well as stars that may be associated with stripped debris from the putative parent dwarf of the globular cluster Omega Centauri, suggested to exist by previous authors. We identify a clear increase in the cumulative frequency of carbon-enhanced metal-poor (CEMP) stars with declining metallicity, as well as an increase in the fraction of CEMP stars with distance from the Galactic plane, consistent with previous results. We also identify a relatively large number of CEMP stars with kinematics consistent with the metal-weak thick-disk population, with possible implications for its origin.
SIMULATION STUDY OF HEMISPHERIC PHASE-ASYMMETRY IN THE SOLAR CYCLE
Authors: Shukuya D. , Kusano K. 
Published: January 2017

ABSTRACT
Observations of the Sun suggest that solar activities systematically create north–south hemispheric asymmetries. For instance, the hemisphere in which sunspot activity is more active tends to switch after the early half of each solar cycle. Svalgaard & Kamide recently pointed out that the time gaps of polar field reversal between the northern and southern hemispheres are simply consequences of the asymmetry of sunspot activity. However, the mechanism underlying the asymmetric feature in solar cycle activity is not yet well understood. In this paper, in order to explain the cause of the asymmetry from the theoretical point of view, we investigate the relationship between the dipole- and quadrupole-type components of the magnetic field in the solar cycle using the mean-field theory based on the flux transport dynamo model. As a result, we found that there are two different attractors of the solar cycle, in which either the north or the south polar field is first reversed, and that the flux transport dynamo model explains well the phase-asymmetry of sunspot activity and the polar field reversal without any ad hoc source of asymmetry.
THE ROLE OF MAGNETIC HELICITY IN STRUCTURING THE SOLAR CORONA
Authors: Knizhnik K. J. , Antiochos S. K. , DeVore C. R. 
Published: January 2017

ABSTRACT
Two of the most widely observed and striking features of the Sun's magnetic field are coronal loops, which are smooth and laminar, and prominences or filaments, which are strongly sheared. Loops are puzzling because they show little evidence of tangling or braiding, at least on the quiet Sun, despite the chaotic nature of the solar surface convection. Prominences are mysterious because the origin of their underlying magnetic structure—filament channels—is poorly understood at best. These two types of features would seem to be quite unrelated and wholly distinct. We argue that, on the contrary, they are inextricably linked and result from a single process: the injection of magnetic helicity into the corona by photospheric motions and the subsequent evolution of this helicity by coronal reconnection. In this paper, we present numerical simulations of the response of a Parker (1972) corona to photospheric driving motions that have varying degrees of helicity preference. We obtain four main conclusions: (1) in agreement with the helicity condensation model of Antiochos (2013), the inverse cascade of helicity by magnetic reconnection in the corona results in the formation of filament channels localized about polarity inversion lines; (2) this same process removes most complex fine structure from the rest of the corona, resulting in smooth and laminar coronal loops; (3) the amount of remnant tangling in coronal loops is inversely dependent on the net helicity injected by the driving motions; and (4) the structure of the solar corona depends only on the helicity preference of the driving motions and not on their detailed time dependence. We discuss the implications of our results for high-resolution observations of the corona.
DETERMINING THE HUBBLE CONSTANT FROM HUBBLE PARAMETER MEASUREMENTS
Authors: Chen Yun , Kumar Suresh , Ratra Bharat 
Published: January 2017

Abstract
We use 28 measurements of the Hubble parameter, H(z), at intermediate redshifts

to determine the present-day Hubble constant H
0 in four cosmological models. We measure

, and

Mpc−1 (1σ errors) in the ΛCDM (spatially flat and non-flat), ωCDM, and ϕCDM models, respectively. These measured H
0 values are more consistent with the lower values determined from recent data on the cosmic microwave background and baryon acoustic oscillations, as well as with the value found from a median statistical analysis of Huchra’s compilation of H
0 measurements, but include the higher local measurements of H
0 within the 2σ confidence limits.
TEST OF PARAMETRIZED POST-NEWTONIAN GRAVITY WITH GALAXY-SCALE STRONG LENSING SYSTEMS
Authors: Cao Shuo , Li Xiaolei , Biesiada Marek , Xu Tengpeng , Cai Yongzhi , Zhu Zong-Hong 
Published: January 2017

ABSTRACT
Based on a mass-selected sample of galaxy-scale strong gravitational lenses from the SLACS, BELLS, LSD, and SL2S surveys and using a well-motivated fiducial set of lens-galaxy parameters, we tested the weak-field metric on kiloparsec scales and found a constraint on the post-Newtonian parameter

under the assumption of a flat ΛCDM universe with parameters taken from Planck observations. General relativity (GR) predicts exactly γ = 1. Uncertainties concerning the total mass density profile, anisotropy of the velocity dispersion, and the shape of the light profile combine to systematic uncertainties of ∼25%. By applying a cosmological model-independent method to the simulated future LSST data, we found a significant degeneracy between the PPN γ parameter and the spatial curvature of the universe. Setting a prior on the cosmic curvature parameter −0.007 < Ω
k
< 0.006, we obtained the constraint on the PPN parameter that

. We conclude that strong lensing systems with measured stellar velocity dispersions may serve as another important probe to investigate validity of the GR, if the mass-dynamical structure of the lensing galaxies is accurately constrained in future lens surveys.
CHIRALITY AND MAGNETIC CONFIGURATIONS OF SOLAR FILAMENTS
Authors: Ouyang (欧阳雨) Y. , Zhou (周雨昊) Y. H. , Chen (陈鹏飞) P. F. , Fang (方成) C. 
Published: January 2017

ABSTRACT
It has been revealed that the magnetic topology in the solar atmosphere displays hemispheric preference, i.e., helicity is mainly negative/positive in the northern/southern hemispheres, respectively. However, the strength of the hemispheric rule and its cyclic variation are controversial. In this paper, we apply a new method based on the filament drainage to 571 erupting filaments from 2010 May to 2015 December in order to determine the filament chirality and its hemispheric preference. It is found that 91.6% of our sample of erupting filaments follows the hemispheric rule of helicity sign. It is also found that the strength of the hemispheric preference of the quiescent filaments decreases slightly from ∼97% in the rising phase to ∼85% in the declining phase of solar cycle 24, whereas the strength of the intermediate filaments keeps a high value around 96 ± 4% at all times. Only the active-region filaments show significant variations. Their strength of the hemispheric rule rises from ∼63% to ∼95% in the rising phase, and keeps a high value of 82% ± 5% during the declining phase. Furthermore, during a half-year period around the solar maximum, their hemispheric preference totally vanishes. Additionally, we also diagnose the magnetic configurations of the filaments based on our indirect method and find that in our sample of erupting events, 89% are inverse-polarity filaments with a flux rope magnetic configuration, whereas 11% are normal-polarity filaments with a sheared arcade configuration.
ACCESS I. AN OPTICAL TRANSMISSION SPECTRUM OF GJ 1214b REVEALS A HETEROGENEOUS STELLAR PHOTOSPHERE
Authors: Rackham Benjamin , Espinoza Néstor , Apai Dániel , López-Morales Mercedes , Jordán Andrés , Osip David J. , Lewis Nikole K. , Rodler Florian , Fraine Jonathan D. , Morley Caroline V. , Fortney Jonathan J. 
Published: January 2017

ABSTRACT
GJ 1214b is the most studied sub-Neptune exoplanet to date. Recent measurements have shown its near-infrared transmission spectrum to be flat, pointing to a high-altitude opacity source in the exoplanet's atmosphere, either equilibrium condensate clouds or photochemical hazes. Many photometric observations have been reported in the optical by different groups, though simultaneous measurements spanning the entire optical regime are lacking. We present an optical transmission spectrum (4500–9260 Å) of GJ 1214b in 14 bins, measured with Magellan/IMACS repeatedly over three transits. We measure a mean planet-to-star radius ratio of

R

p

/

R

s

=
0.1146
±
2
×

10

−
4

and mean uncertainty of

σ
(

R

p

/

R

s

)
=
8.7
×

10

−
4

in the spectral bins. The optical transit depths are shallower on average than observed in the near-infrared. We present a model for jointly incorporating the effects of a composite photosphere and atmospheric transmission through the exoplanet's limb (the CPAT model), and use it to examine the cases of absorber and temperature heterogeneities in the stellar photosphere. We find the optical and near-infrared measurements are best explained by the combination of (1) photochemical haze in the exoplanetary atmosphere with a mode particle size r = 0.1 μm and haze-forming efficiency

f

haze

=
10
%

and (2) faculae in the unocculted stellar disk with a temperature contrast

Δ
T
=

354

−
46

+
46

K, assuming 3.2% surface coverage. The CPAT model can be used to assess potential contributions of heterogeneous stellar photospheres to observations of exoplanet transmission spectra, which will be important for searches for spectral features in the optical.
SYSTEMATIC VARIATIONS OF MACROSPICULE PROPERTIES OBSERVED BY SDO/AIA OVER HALF A DECADE
Authors: Kiss T. S. , Gyenge N. , Erdélyi R. 
Published: January 2017

ABSTRACT
Macrospicules (MSs) are localized small-scale jet-like phenomena in the solar atmosphere, which have the potential to transport a considerable amount of momentum and energy from the lower solar atmospheric regions to the transition region and the low corona. A detailed statistical analysis of their temporal behavior and spatial properties is carried out in this work. Using state-of-the-art spatial and temporal resolution observations, yielded by the Atmospheric Imaging Assembly of Solar Dynamics Observatory, we constructed a database covering a 5.5 year long period, containing 301 macrospicules that occurred between 2010 June and 2015 December, detected at 30.4 nm wavelength. Here, we report the long-term variation of the height, length, average speed, and width of MS in coronal holes and Quiet Sun areas both in the northern and southern hemisphere of the Sun. This new database helps to refine our knowledge about the physical properties of MSs. Cross-correlation of these properties shows a relatively strong correlation, but not always a dominant one. However, a more detailed analysis indicates a wave-like signature in the behavior of MS properties in time. The periods of these long-term oscillatory behaviors are just under two years. Also, in terms of solar north/south hemispheres, a strong asymmetry was found in the spatial distribution of MS properties, which may be accounted for by the solar dynamo. This latter feature may then indicate a strong and rather intrinsic link between global internal and local atmospheric phenomena in the Sun.
HST PanCET Program: A Cloudy Atmosphere for the Promising JWST Target WASP-101b
Authors: Wakeford H. R. , Stevenson K. B. , Lewis N. K. , Sing D. K. , López-Morales M. , Marley M. , Kataria T. , Mandell A. , Ballester G. E. , Barstow J. , Ben-Jaffel L. , Bourrier V. , Buchhave L. A. , Ehrenreich D. , Evans T. , García Muñoz A. , Henry G. , Knutson H. , Lavvas P. , Lecavelier des Etangs A. , Nikolov N. , Sanz-Forcada J. 
Published: January 2017

Abstract
We present results from the first observations of the Hubble Space Telescope (HST) Panchromatic Comparative Exoplanet Treasury program for WASP-101b, a highly inflated hot Jupiter and one of the community targets proposed for the James Webb Space Telescope (JWST) Early Release Science (ERS) program. From a single HST Wide Field Camera 3 observation, we find that the near-infrared transmission spectrum of WASP-101b contains no significant H2O absorption features and we rule out a clear atmosphere at 13σ. Therefore, WASP-101b is not an optimum target for a JWST ERS program aimed at observing strong molecular transmission features. We compare WASP-101b to the well-studied and nearly identical hot Jupiter WASP-31b. These twin planets show similar temperature–pressure profiles and atmospheric features in the near-infrared. We suggest exoplanets in the same parameter space as WASP-101b and WASP-31b will also exhibit cloudy transmission spectral features. For future HST exoplanet studies, our analysis also suggests that a lower count limit needs to be exceeded per pixel on the detector in order to avoid unwanted instrumental systematics.