bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Independent Analysis of the Spitzer/IRAC Phase Curves of WASP43 b
Authors: Morello G. , Danielski C. , Dickens D. , Tremblin P. , Lagage P.-O. 
Published: May 2019

Abstract
We present here a reanalysis of the Spitzer Space Telescope phase curves of the hot Jupiter WASP43 b, using the wavelet pixel-independent component analysis, a blind signal-source separation method. The data analyzed were recorded with the Infrared Array Camera and consisted of two visits at 3.6 μm, and one visit at 4.5 μm, each visit covering one transit and two eclipse events. To test the robustness of our technique we repeated the analysis on smaller portions of the phase curves, and by employing different instrument ramp models. Our reanalysis presents significant updates of the planetary parameters compared to those reported in the original phase curve study of WASP43 b. In particular, we found (1) higher nightside temperatures, (2) smaller hotspot offsets, (3) a greater consistency (∼1σ) between the two 3.6 μm visits, and (4) a greater similarity with the predictions of the atmospheric circulation models. Our parameter results are consistent within 1σ with those reported by a recent reanalysis of the same data sets. For each visit we studied the variation of the retrieved transit parameters as a function of various sets of stellar limb-darkening coefficients, finding significant degeneracy between the limb-darkening models and the analysis output. Furthermore, we performed the analysis of the single transit and eclipse events, and we examined the differences between these results with the ones obtained with the whole phase curve. Finally we provide a formula useful to optimize the trade-off between precision and duration of observations of transiting exoplanets.
Deriving Iodine-free Spectra for High-resolution Echelle Spectrographs*
Authors: Díaz Matías R. , Shectman Stephen A. , Paul Butler R. , Jenkins James S. 
Published: May 2019

Abstract
We describe a new method to derive clean, iodine-free spectra directly from observations acquired using high-resolution echelle spectrographs equipped with iodine cells. The main motivation to obtain iodine-free spectra is to use portions of the spectrum that are superimposed with the dense forest of iodine absorption lines, in order to retrieve lines that can be used to monitor the magnetic activity of the star, helping to validate candidate planets. In short, we provide a straightforward methodology to clean the spectra using the forward model used to derive radial velocities, the line spread function information plus the stellar spectrum without iodine to reconstruct and subtract the iodine spectrum from the observations. We show our results using observations of the star τ Ceti acquired with the Planet Finder Spectrograph (PFS), High Resolution Echelle Spectrometer (HIRES), and University College London Echelle Spectrograph (UCLES), reaching an iodine-free spectrum correction at the ∼1% rms level. We additionally discuss the limitations and further applications of the method.
Multiband Photometry of a Patroclus–Menoetius Mutual Event: Constraints on Surface Heterogeneity
Authors: Wong Ian , Brown Michael E. 
Published: May 2019

Abstract
We present the first complete multiband observations of a binary asteroid mutual event. We obtained high-cadence, high-signal-to-noise photometry of the UT 2018 April 9 inferior shadowing event in the Jupiter Trojan binary system Patroclus–Menoetius in four Sloan bands—g′, r′, i′, and z′. We use an eclipse light-curve model to fit for a precise mideclipse time and estimate the minimum separation of the two eclipsing components during the event. Our best-fit mideclipse time of

is 19 minutes later than the prediction of Grundy et al. The minimum separation between the center of Menoetius’s shadow and the center of Patroclus is 72.5 ± 0.7 km—slightly larger than the predicted 69.5 km. Using the derived light curves, we find no evidence for significant albedo variations or large-scale topographic features on the Earth-facing hemisphere and limb of Patroclus. We also apply the technique of eclipse mapping to place an upper bound of ∼0.15 mag on wide-scale surface color variability across Patroclus.
Alignment between Filaments and Galaxy Spins from the MaNGA Integral-field Survey
Authors: Krolewski Alex , Ho Shirley , Chen Yen-Chi , Chan P. F. , Tenneti Ananth , Bizyaev Dmitry , Kraljic Katarina 
Published: May 2019

Abstract
Halos and galaxies acquire their angular momentum during the collapse of the surrounding large-scale structure. This process imprints alignments between galaxy spins and nearby filaments and sheets. Low-mass halos grow by accretion onto filaments, aligning their spins with the filaments, whereas high-mass halos grow by mergers along filaments, generating spins perpendicular to the filament. We search for this alignment signal using filaments identified with the “Cosmic Web Reconstruction” algorithm applied to the Sloan Digital Sky Survey Main Galaxy Sample and galaxy spins from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) integral-field unit survey. MaNGA produces a map of the galaxy’s rotational velocity, allowing direct measurement of the galaxy’s spin direction, or unit angular momentum vector projected onto the sky. We find no evidence for alignment between galaxy spins and filament directions. We do find hints of a mass-dependent alignment signal, which is in 2σ–3σ tension with the mass-dependent alignment signal in the MassiveBlack-II and Illustris hydrodynamical simulations. However, the tension vanishes when galaxy spin is measured using the Hα emission line velocity rather than stellar velocity. Finally, in simulations we find that the mass-dependent transition from aligned to anti-aligned dark matter halo spins is not necessarily present in stellar spins: we find a stellar spin transition in Illustris but not in MassiveBlack-II, highlighting the sensitivity of spin-filament alignments to feedback prescriptions and subgrid physics.
The Dynamics of AR 12700 in Its Early Emerging Phase. I. Interchange Reconnection
Authors: Zhong Sihui , Hou Yijun , Zhang Jun 
Published: May 2019

Abstract
The emergence of active regions (ARs) leads to various dynamic activities. Using high-resolution and long-lasting Hα observations from the New Vacuum Solar Telescope, we report the dynamics of NOAA AR 12700 in its emerging phase on 2018 February 26 in detail. In this AR, constant interchange reconnections (IRs) between emerging fibrils and preexisting ones were detected. Driven by the flux emergence, small-scale fibrils observed in Hα wavelength continuously emerged at the center of the AR and reconnected with the ambient preexisting fibrils, forming new longer fibrils. We investigate three IR scenarios that occurred over two hours. Specially, the third scenario of reconnection resulted in the formation of longer fibrils that show pronounced rotation motion. To derive the evolution of the magnetic structure during the reconnections, we perform nonlinear force-free field extrapolations. The extrapolated three-dimensional magnetic fields clearly depict a set of almost potential emerging loops, two preexisting flux ropes at 03:00 UT before the second reconnection scenario, and a set of newly formed loops with less twist at 03:48 UT after the third reconnection scenario. All of these extrapolated structures are consistent with the fibrils detected at the Hα wavelength. The aforementioned observations and extrapolation results suggest that the constant IRs resulted in the magnetic twist being redistributed from preexisting flux ropes toward the newly formed system with longer magnetic structure and weaker twist.
SDSS-IV eBOSS Spectroscopy of X-Ray and WISE AGNs in Stripe 82X: Overview of the Demographics of X-Ray- and Mid-infrared-selected Active Galactic Nuclei
Authors: LaMassa Stephanie M. , Georgakakis Antonis , Vivek M. , Salvato Mara , Ananna Tonima Tasnim , Urry C. Meg , MacLeod Chelsea , Ross Nicholas 
Published: May 2019

Abstract
We report the results of a Sloan Digital Sky Survey IV eBOSS program to target X-ray sources and mid-infrared-selected Wide-field Infrared Survey Explorer (WISE) active galactic nucleus (AGN) candidates in a 36.8 deg2 region of Stripe 82. About half this survey (15.6 deg2) covers the largest contiguous portion of the Stripe 82 X-ray survey. This program represents the largest spectroscopic survey of AGN candidates selected solely by their WISE colors. We combine this sample with X-ray and WISE AGNs in the field identified via other sources of spectroscopy, producing a catalog of 4847 sources that is 82% complete to r ∼ 22. Based on X-ray luminosities or WISE colors, 4730 of these sources are AGNs, with a median sample redshift of z ∼ 1. About 30% of the AGNs are optically obscured (i.e., lack broad lines in their optical spectra). BPT analysis, however, indicates that 50% of the WISE AGNs at z < 0.5 have emission line ratios consistent with star-forming galaxies, so whether they are buried AGNs or star-forming galaxy contaminants is currently unclear. We find that 61% of X-ray AGNs are not selected as mid-infrared AGNs, with 22% of X-ray AGNs undetected by WISE. Most of these latter AGNs have high X-ray luminosities (L
x > 1044 erg s−1), indicating that mid-infrared selection misses a sizable fraction of the highest luminosity AGNs, as well as lower luminosity sources where AGN-heated dust is not dominating the mid-infrared emission. Conversely, ∼58% of WISE AGNs are undetected by X-rays, though we do not find that they are preferentially redder than the X-ray-detected WISE AGNs.
Kinematics of the Broad-line Region of 3C 273 from a 10 yr Reverberation Mapping Campaign
Authors: Zhang Zhi-Xiang , Du Pu , Smith Paul S. , Zhao Yulin , Hu Chen , Xiao Ming , Li Yan-Rong , Huang Ying-Ke , Wang Kai , Bai Jin-Ming , Ho Luis C. , Wang Jian-Min 
Published: May 2019

Abstract
Despite many decades of study, the kinematics of the broad-line region of 3C 273 are still poorly understood. We report a new, high signal-to-noise, reverberation mapping campaign carried out from 2008 November to 2018 March that allows the determination of time lags between emission lines and the variable continuum with high precision. The time lag of variations in Hβ relative to those of the 5100 Å continuum is

days in the rest frame, which agrees very well with the Paschen-α region measured by the GRAVITY at The Very Large Telescope Interferometer. The time lag of the Hγ emission line is found to be nearly the same as that for Hβ. The lag of the Fe ii emission is

days, longer by a factor of ∼2 than that of the Balmer lines. The velocity-resolved lag measurements of the Hβ line show a complex structure that can be possibly explained by a rotation-dominated disk with some inflowing radial velocity in the Hβ-emitting region. Taking the virial factor of f
BLR = 1.3, we derive a BH mass of

and an accretion rate of

from the Hβ line. The decomposition of its Hubble Space Telescope images yields a host stellar mass of

, and a ratio of

in agreement with the Magorrian relation. In the near future, it is expected to compare the geometrically thick BLR discovered by the GRAVITY in 3C 273 with its spatially resolved torus in order to understand the potential connection between the BLR and the torus.
The Dark Side of Penumbral Microjets: Observations in Hα
Authors: Buehler D. , Pozuelo S. Esteban , de la Cruz Rodriguez J. , Scharmer G. B. 
Published: May 2019

Abstract
We present data of 10 penumbral microjets (PMJs) observed in a Hα, Ca ii 8542 Å, and Fe i 6302 Å line pair with the Swedish 1 m Solar Telescope (SST) with CRISP and Ca ii K with SST/CHROMIS in active region NOAA 12599 on 2016 October 12 at μ = 0.68. All four Stokes parameters of the Ca ii 8542 Å and Fe i 6302 Å lines were observed and a series of test pixels were inverted using the Stockholm inversion code. Our analysis revealed for the first time that PMJs are visible in Hα, where they appear as dark features with average line-of-sight (LOS) upflows of 1.1 ± 0.6 km s−1, matching the LOS velocities from the inversions. Based on the Hα observations we extend the previous average length and lifetime of PMJs to 2815 ± 530 km and 163 ± 25 s, respectively. The plane-of-sky (POS) velocities of our PMJs of up to 17 km s−1 tend to give increased velocities with distance traveled. Furthermore, two of our PMJs with significant Stokes V signal indicate that the PMJs possess an increased LOS magnetic field of up to 100 G compared to the local pre-/post- PMJ magnetic field, which propagates as quickly as the PMJs’ POS velocities. Finally, we present evidence that PMJs display an on average 1 minute gradual precursory brightening that only manifests itself in the cores of the Ca ii lines. We conclude that PMJs are not ordinary jets but likely are manifestations of heat fronts that propagate at the local Alfvén velocity.
Suprathermal Ions in the Outer Heliosphere
Authors: Kollmann Peter , Hill M. E. , McNutt R. L. , Brown L. E. , Allen R. C. , Clark G. , Andrews B. , Salazar N. , Westlake J. , Romeo G. , Vandegriff J. , Kusterer M. , Smith D. , Jaskulek S. , Decker R. , Cheng A. F. , Krimigis S. M. , Lisse C. M. , Mitchell D. G. , Weaver H. A. , Delamere P. , Elliott H. A. , Fattig E. , Gladstone G. R. , Valek P. W. , Weidner S. , Bagenal F. , Horányi M. , Kammer J. A. , Kaufmann D. , Olkin C. B. , Piquette M. R. , Spencer J. R. , Steffl A. J. , Stern S. A. , Young L. A. , Ennico K. , Linscott I. R. , Strobel D. F. , Summers M. E. , Szalay J. R. 
Published: May 2019

Abstract
Suprathermal ions form from interstellar gas that is first ionized into pickup ions and then accelerated to tens and hundreds of keV in energy. The resulting suprathermal ion spectra with hundreds of keV have been previously observed throughout the heliosphere; however, measurements at lower energies, around the pickup ion cutoff energy where they are accelerated from, were limited to <10 au. Here we present a statistical study of suprathermal ions in the keV to hundred keV energy range. We use the Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) instrument on the New Horizons spacecraft, which recorded observations at a wide range of heliocentric distances, and compare these measurements to charge energy mass spectrometer (CHEMS) observations on Cassini, which cruised to and remained at Saturn. We find that the power-law exponents of suprathermal ion intensity over energy are between −1 and −2, change abruptly close to discontinuities that are likely corotating merged interaction regions, correlate with the solar wind bulk speed, and show a long-term evolution on the timescale of the solar cycle. The independent measurements from New Horizons and Cassini are consistent, confirming the first fully calibrated measurements from the New Horizons/PEPSSI instrument.
Fluorine Abundances in the Globular Cluster M4
Authors: Guerço Rafael , Cunha Katia , Smith Verne V. , Pereira Claudio B. , Abia Carlos , Lambert David L. , de Laverny Patrick , Recio-Blanco Alejandra , Jönsson Henrik 
Published: May 2019

Abstract
We present chemical abundances for the elements carbon, sodium, and fluorine in 15 red giants of the globular cluster M4, as well as six red giants of the globular cluster ω Centauri. The chemical abundances were calculated in LTE via spectral synthesis. The spectra analyzed are high-resolution spectra obtained in the near-infrared region around 2.3 μm with the Phoenix spectrograph on the 8.1 m Gemini South Telescope, the IGRINS spectrograph on the McDonald Observatory 2.7 m Telescope, and the CRIRES spectrograph on the ESO 8.2 m Very Large Telescope. The results indicate a significant reduction in the fluorine abundances when compared to previous values from the literature for M4 and ω Centauri, due to a downward revision in the excitation potentials of the HF (1−0) R9 line used in the analysis. The fluorine abundances obtained for the M4 red giants are found to be anticorrelated with those of Na, following the typical pattern of abundance variations seen in globular clusters between distinct stellar populations. In M4, as the Na abundance increases by ∼+0.4 dex, the F abundance decreases by ∼−0.2 dex. A comparison with abundance predictions from two sets of stellar evolution models finds that the models predict somewhat less F depletion (∼−0.1 dex) for the same increase of +0.4 dex in Na.
Absolute Dimensions of the Early F-type Eclipsing Binary V506 Ophiuchi
Authors: Torres Guillermo , Sandberg Lacy Claud H. , Fekel Francis C. , Muterspaugh Matthew W. 
Published: May 2019

Abstract
We report extensive differential V-band photometry and high-resolution spectroscopic observations of the early F-type, 1.06-day detached eclipsing binary V506 Oph. The observations, along with times of minimum light from the literature, are used to derive a very precise ephemeris and the physical properties for the components, with the absolute masses and radii being determined to 0.7% or better. The masses are 1.4153 ± 0.0100 M
☉ and 1.4023 ± 0.0094 M
☉ for the primary and secondary, the radii are 1.725 ± 0.010 R
☉ and 1.692 ± 0.012 R
☉, and the effective temperatures are 6840 ± 150 K and 6780 ± 110 K, respectively. The orbit is circular and the stars are rotating synchronously. The accuracy of the radii and temperatures is supported by the resulting distance estimate of 564 ± 30 pc, which is in excellent agreement with the value implied by the trigonometric parallax listed in the Gaia/Data Release 2 catalog. Current stellar evolution models from the Modules for Experiments in Stellar Astrophysics (MESA) Isochrones and Stellar Tracks series for a composition of [Fe/H] = −0.04 match the properties of both stars in V506 Oph very well at an age of 1.83 Gyr and indicate they are halfway through their core hydrogen-burning phase.
An Atlas of Coronal Electron Density at 5R⊙. II. A Spherical Harmonic Method for Density Reconstruction
Authors: Morgan Huw 
Published: May 2019

Abstract
This is the second of a series of three papers that present a methodology with the aim of creating a set of maps of the coronal density over a period of many years. This paper describes a method for reconstructing the coronal electron density based on spherical harmonics. By assuming a radial structure to the corona at the height of interest, line-of-sight integrations can be made individually on each harmonic basis prior to determining coefficients, i.e., the computationally expensive integrations are calculated only once during initialization. This approach reduces the problem to finding the set of coefficients that best match the observed brightness using a regularized least-squares approach and is very efficient. The method is demonstrated on synthetic data created from both a simple and an intricate coronal density model. The quality of reconstruction is found to be reasonable in the presence of noise and large gaps in the data. The method is applied to both Large Angle and Spectrometric Coronagraph Experiment C2 and Solar
Terrestrial Relations Observatory Cor2 coronagraph observations from 2009 March 20, and the results from both spacecraft compared. Future work will apply the method to large data sets.
Core Cosmology Library: Precision Cosmological Predictions for LSST
Authors: Chisari Nora Elisa , Alonso David , Krause Elisabeth , Leonard C. Danielle , Bull Philip , Neveu Jérémy , Villarreal Antonio , Singh Sukhdeep , McClintock Thomas , Ellison John , Du Zilong , Zuntz Joe , Mead Alexander , Joudaki Shahab , Lorenz Christiane S. , Tröster Tilman , Sanchez Javier , Lanusse Francois , Ishak Mustapha , Hlozek Renée , Blazek Jonathan , Campagne Jean-Eric , Almoubayyed Husni , Eifler Tim , Kirby Matthew , Kirkby David , Plaszczynski Stéphane , Slosar Anže , Vrastil Michal , Wagoner Erika L. ,   (LSST Dark Energy Science Collaboration)
Published: May 2019

Abstract
The Core Cosmology Library (CCL) provides routines to compute basic cosmological observables to a high degree of accuracy, which have been verified with an extensive suite of validation tests. Predictions are provided for many cosmological quantities, including distances, angular power spectra, correlation functions, halo bias, and the halo mass function through state-of-the-art modeling prescriptions available in the literature. Fiducial specifications for the expected galaxy distributions for the Large Synoptic Survey Telescope (LSST) are also included, together with the capability of computing redshift distributions for a user-defined photometric redshift model. A rigorous validation procedure, based on comparisons between CCL and independent software packages, allows us to establish a well-defined numerical accuracy for each predicted quantity. As a result, predictions for correlation functions of galaxy clustering, galaxy–galaxy lensing, and cosmic shear are demonstrated to be within a fraction of the expected statistical uncertainty of the observables for the models and in the range of scales of interest to LSST. CCL is an open source software package written in C, with a Python interface and publicly available at https://github.com/LSSTDESC/CCL.
SPECTRUM: Synthetic Spectral Calculations for Global Space Plasma Modeling
Authors: Szente J. , Landi E. , Manchester W. B. , Toth G. , van der Holst B. , Gombosi T. I. 
Published: May 2019

Abstract
High-resolution spectroscopy is the most accurate tool for measuring the properties of the solar corona. However, interpreting measured line intensities and line profiles emitted by the optically thin solar corona is complicated by line-of-sight (LOS) integration, which leads to measuring weighted averages of the plasma properties along the LOS. LOS integration effects can be removed by combining CHIANTI spectral emissivities with a 3D global model of the solar corona to calculate the contribution of all structures along the LOS to the measured intensities. In this paper, we describe SPECTRUM, a postprocessing tool that can calculate the emission from the optically thin solar corona by combining 3D magnetohydrodynamic (MHD) space plasma simulation results with the CHIANTI database. Doppler-shifted, nonthermal line broadening due to low-frequency Alfvén waves and anisotropic proton and isotropic electron temperatures can be individually taken into account during calculations. Synthetic spectral calculations can then be used for model validation, for interpretation of solar observations, and for forward modeling purposes. SPECTRUM is implemented within the Space Weather Modeling Framework (SWMF) and is therefore publicly available. In this paper, we describe the SPECTRUM module and show its applications by comparing synthetic spectra using simulation data by the 3D MHD Alfvén Wave Solar Model with observations done by the Hinode/Extreme-ultraviolet Imaging Spectrometer during Carrington rotations 2063 and 2082.