bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Emission Spectrum of the Hot Jupiter WASP-79b from HST/WFC3
Authors: Foote Trevor O. , Lewis Nikole K. , Kilpatrick Brian M. , Goyal Jayesh M. , Bruno Giovanni , Wakeford Hannah R. , Robbins-Blanch Nina , Kataria Tiffany , MacDonald Ryan J. , López-Morales Mercedes , Sing David K. , Mikal-Evans Thomas , Bourrier Vincent , Henry Gregory , Buchhave Lars A. 
Published: December 2021

Abstract
Here we present a thermal emission spectrum of WASP-79b, obtained via Hubble Space Telescope Wide Field Camera 3 G141 observations as part of the PanCET program. As we did not observe the ingress or egress of WASP-79b’s secondary eclipse, we consider two scenarios: a fixed mid-eclipse time based on the expected occurrence time, and a mid-eclipse time as a free parameter. In both scenarios, we can measure thermal emission from WASP-79b from 1.1 to 1.7 μm at 2.4σ confidence consistent with a 1900 K brightness temperature for the planet. We combine our observations with Spitzer dayside photometry (3.6 and 4.5 μm) and compare these observations to a grid of atmospheric forward models that span a range of metallicities, carbon-to-oxygen ratios, and recirculation factors. Given the strength of the planetary emission and the precision of our measurements, we found a wide range of forward models to be consistent with our data. The best-match equilibrium model suggests that WASP-79b’s dayside has a solar metallicity and carbon-to-oxygen ratio, alongside a recirculation factor of 0.75. Models including significant H− opacity provide the best match to WASP-79b’s emission spectrum near 1.58 μm. However, models featuring high-temperature cloud species—formed via vigorous vertical mixing and low sedimentation efficiencies—with little day-to-night energy transport also match WASP-79b’s emission spectrum. Given the broad range of equilibrium chemistry, disequilibrium chemistry, and cloudy atmospheric models consistent with our observations of WASP-79b’s dayside emission, further observations will be necessary to constrain WASP-79b’s dayside atmospheric properties.
Searching for Diamagnetic Blob Accretion in the 74 day K2 Observation of V2400 Ophiuchi
Authors: Langford Andrew , Littlefield Colin , Garnavich Peter , Kennedy Mark R. , Scaringi Simone , Szkody Paula 
Published: December 2021

Abstract
Since its discovery in 1995, V2400 Ophiuchi (V2400 Oph) has stood apart from most known intermediate polar cataclysmic variables due to its proposed magnetic field strength (9–27 MG) and diskless accretion. To date, the exact accretion mechanism of the system is still unknown, and standard accretion models fail to accurately predict the peculiar behavior of its light curve. We present the K2 Campaign 11 light curve of V2400 Oph recording 74.19 days of photometric data cadenced at 1 minute. The light curve is dominated by aperiodic flickering and quasiperiodic oscillations, which make the beat and spin signals inconspicuous on short timescales. Notably, a log–log full power spectrum shows a break frequency at ∼102 cycles d−1 similar to some disk-fed systems. Through power-spectral analysis, the beat and spin periods are measured as 1003.4 ± 0.2 s and 927.7 ± 0.1 s, respectively. A power spectrum of the entire K2 observation demonstrates beat period dominance. However, time-resolved power spectra reveal a strong dependence between observation length and the dominant frequency of the light curve. For short observations (2–12 hr) the beat, spin, or first beat harmonic can be observed as the dominant periodic signal. Such incoherence and variability indicate a dynamical accretion system more complex than current intermediate polar theories can explain. We propose that a diamagnetic blob accretion model may serve as a plausible explanation for the accretion mechanism.
Terrestrial Planet Optical Phase Curves. I. Direct Measurements of the Earth
Authors: De Cock Roderick , Livengood Timothy A. , Stam Daphne M. , Lisse Carey M. , Hewagama Tilak , Deming L. Drake 
Published: December 2021

Abstract
NASA’s EPOXI mission used the Deep Impact spacecraft to observe the disk-integrated Earth as an analog to terrestial exoplanets’ appearance. The mission took five 24 hr observations in 2008–2009 at various phase angles (57.°7–86.°4) and ranges (0.11–0.34 au), of which three equatorial (E1, E4, E5) and two polar (P1, North and P2, South). The visible data taken by the HRIV instrument ranges from 0.3 to 1.0 μm, taken trough seven spectral filters that have spectral widths of about 100 nm, and which are centered about 100 nm apart, from 350 to 950 nm. The disk-integrated, 24 hr averaged signal is used in a phase angle analysis. A Lambertian-reflecting, spherical planet model is used to estimate geometric albedo for every observation and wavelength. The geometric albedos range from 0.143 (E1, 950 nm) to 0.353 (P2, 350 nm) and show wavelength dependence. The equatorial observations have similar values, while the polar observations have higher values due to the ice in view. Therefore, equatorial observations can be predicted for other phase angles, but (Earth-like) polar views (with ice) would be underestimated.
Stellar Population and Elemental Abundance Gradients of Early-type Galaxies*
Authors: Feldmeier-Krause A. , Lonoce I. , Freedman W. L. 
Published: December 2021

Abstract
The evolution of galaxies is imprinted on their stellar populations. Several stellar population properties in massive early-type galaxies have been shown to correlate with intrinsic galaxy properties such as the galaxy’s central velocity dispersion, suggesting that stars formed in an initial collapse of gas (z ∼ 2). However, stellar populations change as a function of galaxy radius, and it is not clear how local gradients of individual galaxies are influenced by global galaxy properties and galaxy environment. In this paper, we study the stellar populations of eight early-type galaxies as a function of radius. We use optical spectroscopy (∼4000–8600 Å) and full spectral fitting to measure stellar population age, metallicity, slope of the initial mass function (IMF), and nine elemental abundances (O, Mg, Si, Ca, Ti, C, N, Na, and Fe) out to 1 R

e
for each galaxy individually. We find a wide range of properties, with ages ranging from 3–13 Gyr. Some galaxies have a radially constant, Salpeter-like IMF, and other galaxies have a super-Salpeter IMF in the center, decreasing to a sub-Salpeter IMF at ∼0.5 R

e
. We find a global correlation of the central [Z/H] with the central IMF and the radial gradient of the IMF for the eight galaxies, but local correlations of the IMF slope with other stellar population parameters hold only for subsets of the galaxies in our sample. Some elemental abundances also correlate locally with each other within a galaxy, suggesting a common production channel. These local correlations appear only in subsets of our galaxies, indicating variations of the stellar content among different galaxies.
Multiphase Outflows in High-redshift Quasar Host Galaxies
Authors: Vayner Andrey , Zakamska Nadia , Wright Shelley A. , Armus Lee , Murray Norman , Walth Gregory 
Published: December 2021

Abstract
We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of six radio-loud quasar host galaxies at z = 1.4–2.3. We combine the kiloparsec-scale resolution ALMA observations with high spatial resolution adaptive optics integral field spectrograph data of the ionized gas. We detect molecular gas emission in five quasar host galaxies and resolve the molecular interstellar medium using the CO (3–2) or CO (4–3) rotational transitions. Clumpy molecular outflows are detected in four quasar host galaxies and a merger system 21 kpc away from one quasar. Between the ionized and cold molecular gas phases, the majority of the outflowing mass is in a molecular phase, while for three out of four detected multiphase gas outflows, the majority of the kinetic luminosity and momentum flux is in the ionized phase. Combining the energetics of the multiphase outflows, we find that their driving mechanism is consistent with energy-conserving shocks produced by the impact of the quasar jets with the gas in the galaxy. By assessing the molecular gas mass to the dynamics of the outflows, we estimate a molecular gas depletion timescale of a few megayears. The gas outflow rates exceed the star formation rates, suggesting that quasar feedback is a major mechanism of gas depletion at the present time. The coupling efficiency between the kinetic luminosity of the outflows and the bolometric luminosity of the quasar of 0.1%–1% is consistent with theoretical predictions. Studying multiphase gas outflows at high redshift is important for quantifying the impact of negative feedback in shaping the evolution of massive galaxies.
A Unified Model for the Fan Region and the North Polar Spur: A Bundle of Filaments in the Local Galaxy
Authors: West J. L. , Landecker T. L. , Gaensler B. M. , Jaffe T. , Hill A. S. 
Published: December 2021

Abstract
We present a simple, unified model that can explain two of the brightest, large-scale, diffuse, polarized radio features in the sky, the North Polar Spur (NPS) and the Fan Region, along with several other prominent loops. We suggest that they are long, magnetized, and parallel filamentary structures that surround the Local arm and/or Local Bubble, in which the Sun is embedded. We show that this model is consistent with the large number of observational studies on these regions and is able to resolve an apparent contradiction in the literature that suggests that the high-latitude portion of the NPS is nearby, while lower-latitude portions are more distant. Understanding the contributions of this local emission is critical to developing a complete model of the Galactic magnetic field. These very nearby structures also provide context to help understand similar nonthermal, filamentary structures that are increasingly being observed with modern radio telescopes.
A Comparison of Circumgalactic Mg ii Absorption between the TNG50 Simulation and the MEGAFLOW Survey
Authors: DeFelippis Daniel , Bouché Nicolas F. , Genel Shy , Bryan Greg L. , Nelson Dylan , Marinacci Federico , Hernquist Lars 
Published: December 2021

Abstract
The circumgalactic medium (CGM) contains information on gas flows around galaxies, such as accretion and supernova-driven winds, which are difficult to constrain from observations alone. Here, we use the high-resolution TNG50 cosmological magnetohydrodynamical simulation to study the properties and kinematics of the CGM around star-forming galaxies in 1011.5–1012
M
⊙ halos at z ≃ 1 using mock Mg ii absorption lines, which we generate by postprocessing halos to account for photoionization in the presence of a UV background. We find that the Mg ii gas is a very good tracer of the cold CGM, which is accreting inward at inflow velocities of up to 50 km s−1. For sight lines aligned with the galaxy’s major axis, we find that Mg ii absorption lines are kinematically shifted due to the cold CGM’s significant corotation at speeds up to 50% of the virial velocity for impact parameters up to 60 kpc. We compare mock Mg ii spectra to observations from the MusE GAs FLow and Wind (MEGAFLOW) survey of strong Mg ii absorbers (EW2796 Å
0 > 0.5 Å). After matching the equivalent-width (EW) selection, we find that the mock Mg ii spectra reflect the diversity of observed kinematics and EWs from MEGAFLOW, even though the sight lines probe a very small fraction of the CGM. Mg ii absorption in higher-mass halos is stronger and broader than in lower-mass halos but has qualitatively similar kinematics. The median-specific angular momentum of the Mg ii CGM gas in TNG50 is very similar to that of the entire CGM and only differs from non-CGM components of the halo by normalization factors of ≲1 dex.
Diffusion of Cosmic Rays in MHD Turbulence with Magnetic Mirrors
Authors: Lazarian Alex , Xu Siyao 
Published: December 2021

Abstract
As the fundamental physical process with many astrophysical implications, the diffusion of cosmic rays (CRs) is determined by their interaction with magnetohydrodynamic (MHD) turbulence. We consider the magnetic mirroring effect arising from MHD turbulence on the diffusion of CRs. Due to the intrinsic superdiffusion of turbulent magnetic fields, CRs with large pitch angles that undergo mirror reflection, i.e., bouncing CRs, are not trapped between magnetic mirrors, but move diffusively along the turbulent magnetic field, leading to a new type of parallel diffusion, i.e., mirror diffusion. This mirror diffusion is in general slower than the diffusion of nonbouncing CRs with small pitch angles that undergo gyroresonant scattering. The critical pitch angle at the balance between magnetic mirroring and pitch-angle scattering is important for determining the diffusion coefficients of both bouncing and nonbouncing CRs and their scalings with the CR energy. We find nonuniversal energy scalings of diffusion coefficients, depending on the properties of MHD turbulence.
Surveying the Bright Stars by Optical Interferometry. III. A Magnitude-limited Multiplicity Survey of Classical Be Stars
Authors: Hutter D. J. , Tycner C. , Zavala R. T. , Benson J. A. , Hummel C. A. , Zirm H. 
Published: December 2021

Abstract
We present the results of a multiplicity survey for a magnitude-limited sample of 31 classical Be stars conducted with the Navy Precision Optical Interferometer and the Mark III Stellar Interferometer. The interferometric observations were used to detect companions in 10 previously known binary systems. For two of these sources (66 Oph and β Cep) new orbital solutions were obtained, while for a third source (υ Sgr) our observations provide the first direct, visual detection of the hot companion to the primary star. Combining our interferometric observations with an extensive literature search, we conclude that an additional four sources (o Cas, 15 Mon, β Lyr, and β Cep) also contain wider binary components that are physical companions to the narrow binaries, thus forming hierarchical multiple systems. Among the sources not previously confirmed as spectroscopic or visual binaries, BK Cam was resolved on a number of nights within a close physical proximity of another star with relative motion possibly suggesting a physical binary. Combining our interferometric observations with an extensive literature search, we provide a detailed listing of companions known around each star in the sample, and discuss the multiplicity frequency in the sample. We also discuss the prospects for future multiplicity studies of classical Be stars by long-baseline optical interferometry.
The Spitzer/IRAC Legacy over the GOODS Fields: Full-depth 3.6, 4.5, 5.8, and 8.0 μm Mosaics and Photometry for >9000 Galaxies at z ∼ 3.5–10 from the GOODS Reionization Era Wide-area Treasury from Spitzer (GREATS)
Authors: Stefanon Mauro , Labbé Ivo , Oesch Pascal A. , De Barros Stephane , Gonzalez Valentino , Bouwens Rychard J. , Franx Marijn , Illingworth Garth D. , Holden Brad , Magee Dan , Smit Renske , van Dokkum Pieter 
Published: December 2021

Abstract
We present the deepest Spitzer/InfraRed Array Camera (IRAC) 3.6, 4.5, 5.8, and 8.0 μm wide-area mosaics yet over the Great Observatories Origins Deep Survey (GOODS)-N and GOODS-S fields as part of the GOODS Reionization Era wide-Area Treasury from Spitzer (GREATS) project. We reduced and mosaicked in a self-consistent way observations taken by the 11 different Spitzer/IRAC programs over the two GOODS fields from 12 yr of Spitzer cryogenic and warm-mission data. The cumulative depth in the 3.6 μm and 4.5 μm bands amounts to ∼4260 hr, ∼1220 hr of which are new very deep observations from the GREATS program itself. In the deepest area, the full-depth mosaics reach ≳200 hr over an area of ∼100 arcmin2, corresponding to a sensitivity of ∼29 AB magnitude at 3.6 μm (1σ for point sources). Archival cryogenic 5.8 μm and 8.0 μm band data (a cumulative 976 hr) are also included in the release. The mosaics are projected onto the tangential plane of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey/GOODS at a 0.″3 pixel−1 scale. This paper describes the methodology enabling, and the characteristics of, the public release of the mosaic science images, the corresponding coverage maps in the four IRAC bands, and the empirical point-spread functions (PSFs). These PSFs enable mitigation of the source blending effects by taking into account the complex position-dependent variation in the IRAC images. The GREATS data products are in the Infrared Science Archive. We also release the deblended 3.6–8.0 μm photometry 9192 Lyman-break galaxies at z ∼ 3.5–10. GREATS will be the deepest mid-infrared imaging until the James Webb Space Telescope and, as such, constitutes a major resource for characterizing early galaxy assembly.
Point-spread Function Deconvolution of the IFU Data and Restoration of Galaxy Stellar Kinematics
Authors: Chung Haeun , Park Changbom , Park Yong-Sun 
Published: December 2021

Abstract
We present a performance test of the point-spread function (PSF) deconvolution algorithm applied to astronomical integral field unit (IFU) spectroscopy data for restoration of galaxy kinematics. We deconvolve the IFU data by applying the Lucy–Richardson algorithm to the 2D image slice at each wavelength. We demonstrate that the algorithm can effectively recover the true stellar kinematics of the galaxy, by using mock IFU data with a diverse combination of surface brightness profile, signal-to-noise ratio, line-of-sight geometry, and line-of-sight velocity distribution (LOSVD). In addition, we show that the proxy of the spin parameter

λ

R

e

can be accurately measured from the deconvolved IFU data. We apply the deconvolution algorithm to the actual SDSS-IV MaNGA IFU survey data. The 2D LOSVD, geometry, and

λ

R

e

measured from the deconvolved MaNGA IFU data exhibit noticeable differences compared to the ones measured from the original IFU data. The method can be applied to any other regular-grid IFU data to extract the PSF-deconvolved spatial information.
Interstellar Extinction and Elemental Abundances: Individual Sight Lines
Authors: Zuo Wenbo , Li Aigen , Zhao Gang 
Published: December 2021

Abstract
While it is well recognized that both the Galactic interstellar extinction curves and the gas-phase abundances of dust-forming elements exhibit considerable variations from one sight line to another, as yet most of the dust extinction modeling efforts have been directed to the Galactic average extinction curve, which is obtained by averaging over many clouds of different gas and dust properties. Therefore, any details concerning the relationship between the dust properties and the interstellar environments are lost. Here we utilize the wealth of extinction and elemental abundance data obtained by space telescopes and explore the dust properties of a large number of individual sight lines. We model the observed extinction curve of each sight line and derive the abundances of the major dust-forming elements (i.e., C, O, Si, Mg, and Fe) required to be tied up in dust (i.e., dust depletion). We then confront the derived dust depletions with the observed gas-phase abundances of these elements and investigate the environmental effects on the dust properties and elemental depletions. It is found that for the majority of the sight lines the interstellar oxygen atoms are fully accommodated by gas and dust and therefore there does not appear to be a “missing oxygen” problem. For those sight lines with an extinction-to-hydrogen column density A

V
/N
H ≳ 4.8 × 10−22 mag cm2 H−1 there are shortages of C, Si, Mg, and Fe elements for making dust to account for the observed extinction, even if the interstellar C/H, Si/H, Mg/H, and Fe/H abundances are assumed to be protosolar abundances augmented by Galactic chemical evolution.
On the early detecting of the COVID-19 outbreak
Authors: Aba Oud Mohammed , Almuqrin Muqrin 
Published: December 2021

Introduction: This paper aims to measure the performance of early detection methods, which are usually used for infectious diseases.
Methodology: By using real data of confirmed Coronavirus cases from the Kingdom of Saudi Arabia and Italy, the moving epidemic method (MEM) and the moving average cumulative sums (Mov. Avg Cusum) methods are used in our simulation study.
Results: Our results suggested that the CUSUM method outperforms the MEM in detecting the start of the Coronavirus outbreak.
Emergence of tigecycline-resistant Klebsiella pneumoniae ST11 clone in patients without exposure to tigecycline
Authors: Goodarzi Rezvan , Arabestani Mohammadreza , Alikhani Mohmmad Yousef , Keramat Fariba , Asghari Babak 
Published: December 2021

Introduction: Tigecycline is a unique class of semi-synthetic glycylcyclines developed to treat infections caused by multidrug-resistant Klebsiella pneumoniae. In the past decades, eight tigecycline-resistant Acinetobacter baumannii isolates have been identified in Tehran and no Klebsiella pneumoniae has been reported.
Methodology: To elucidate the mechanism of K. pneumoniae efflux pump-mediated resistance, the expression of efflux pump genes (oqxA, oqxB, acrA, acrB, tolC) and regulators (acrR, ramA, marA, soxS, rarA, rob) was investigated by real-time RT-PCR. Multilocus sequence typing (MLST) of tigecycline-resistant strains was also performed.
Results: Compared to the tigecycline sensitive strain K32 (negative control), all resistant strains showed higher expression levels of efflux genes and regulatory factors. Three tigecycline-resistant strains (K53, K67, K79) showed higher levels of rarA expression (38.1-fold, 41-fold and 24-fold, respectively) and oqxB pump gene (48.2-fold, 60-fold and 58-fold, respectively). The increased expression of acrB was associated with the expression of ramA. However, to the best of our knowledge, studies on the mechanisms of resistance of K. pneumoniae strains to tigecycline are limited, especially in developing countries such as Iran.
Conclusions: In the present study, we found that both AcrAB-TolC and OqxAB efflux pumps may play an important role in tigecycline resistance in K. pneumoniae isolates. Finally, the emergence of ST11 molecular type of resistant isolates should be monitored in hospitals to identify factors leading to tigecycline resistance.