Search Publications
Distant Relatives: The Chemical Homogeneity of Comoving Pairs Identified in Gaia
Ting, Yuan-Sen; Hawkins, Keith; El-Badry, Kareem +3 more
Comoving pairs, even at the separations of ${ \mathcal O }({10}^{6})$ au, are a predicted reservoir of conatal stars. We present detailed chemical abundances of 62 stars in 31 comoving pairs with separations of 102-107 au and 3D velocity differences <2 km s-1. This sample includes both bound comoving pairs/wide …
NGC 5128 Globular Cluster Candidates Out to 150 kpc: A Comprehensive Catalog from Gaia and Ground-based Data
Forbes, Duncan A.; Caldwell, Nelson; Strader, Jay +9 more
We present a new catalog of 40,502 globular cluster (GC) candidates in NGC 5128 out to a projected radius of ~150 kpc based on data from the Panoramic Imaging Survey of Centaurus and Sculptor, the Gaia Data Release 2, and the NOAO Source Catalog. Ranking these candidates based on the likelihood that they are true GCs, we find that approximately 19…
Observations of Magnetic Fields Surrounding LkHα 101 Taken by the BISTRO Survey with JCMT-POL-2
Zhang, Yapeng; Pattle, Kate; Ward-Thompson, Derek +146 more
We report the first high spatial resolution measurement of magnetic fields surrounding LkHα 101, part of the Auriga-California molecular cloud. The observations were taken with the POL-2 polarimeter on the James Clerk Maxwell Telescope within the framework of the B-fields In Star-forming Region Observations (BISTRO) survey. Observed polarization o…
Extensive Lensing Survey of Optical and Near-infrared Dark Objects (El Sonido): HST H-faint Galaxies behind 101 Lensing Clusters
Pérez-González, Pablo G.; Koekemoer, Anton M.; Smail, Ian +22 more
We present a Spitzer/IRAC survey of H-faint (H 160 ≳ 26.4, < 5σ) sources in 101 lensing cluster fields. Across a CANDELS/Wide-like survey area of ~648 arcmin2 (effectively ~221 arcmin2 in the source plane), we have securely discovered 53 sources in the IRAC Channel-2 band (CH2, 4.5 µm; median CH2 = 22.46 ±…
Detection of Flare Multiperiodic Pulsations in Mid-ultraviolet Balmer Continuum, Lyα, Hard X-Ray, and Radio Emissions Simultaneously
Li, Gang; Gan, Weiqun; Li, Xiaobo +7 more
Quasi-periodic pulsations (QPPs), which usually appear as temporal pulsations of the total flux, are frequently detected in the light curves of solar/stellar flares. In this study, we present the investigation of nonstationary QPPs with multiple periods during the impulsive phase of a powerful flare on 2017 September 6, which were simultaneously m…
Testing Evolutionary Models with Red Supergiant and Wolf-Rayet Populations
Massey, Philip; Dorn-Wallenstein, Trevor Z.; Levesque, Emily M. +3 more
Despite the many successes that modern massive star evolutionary theory has enjoyed, reproducing the apparent trend in the relative number of red supergiants (RSGs) and Wolf-Rayet (WR) stars has remained elusive. Previous estimates show the RSG/WR ratio decreasing strongly with increasing metallicity. However, the evolutionary models have always p…
The Nature of Soft Excess in ESO 362-G18 Revealed by XMM-Newton and NuSTAR Spectroscopy
Walton, Dominic J.; García, Javier A.; Harrison, Fiona A. +3 more
We present a detailed spectral analysis of the joint XMM-Newton and NuSTAR observations of the active galactic nuclei (AGNs) in the Seyfert 1.5 Galaxy ESO 362-G18. The broadband (0.3-79 keV) spectrum shows the presence of a power-law continuum with a soft excess below 2 keV, iron Kα emission (∼6.4 keV), and a Compton hump (peaking at ∼20 keV). We …
The Fundamental Plane in the LEGA-C Survey: Unraveling the M/L Ratio Variations of Massive Star-forming and Quiescent Galaxies at z ∼ 0.8
Bell, Eric F.; Maseda, Michael V.; D'Eugenio, Francesco +10 more
We explore the connection between the kinematics, structures and stellar populations of massive galaxies at 0.6 < z < 1.0 using the fundamental plane (FP). Combining stellar kinematic data from the Large Early Galaxy Astrophysics Census (LEGA-C) survey with structural parameters measured from deep Hubble Space Telescope imaging, we obtain a …
Uniform Forward-modeling Analysis of Ultracool Dwarfs. I. Methodology and Benchmarking
Line, Michael R.; Marley, Mark S.; Liu, Michael C. +2 more
We present a forward-modeling framework using the Bayesian inference tool Starfish and cloudless Sonora-Bobcat model atmospheres to analyze low-resolution (R ≈ 80-250) near-infrared (1.0-2.5 µm) spectra of T dwarfs. Our approach infers effective temperatures, surface gravities, metallicities, radii, and masses, and by accounting for uncertai…
Revealing the Structure and Internal Rotation of the Sagittarius Dwarf Spheroidal Galaxy with Gaia and Machine Learning
van der Marel, Roeland P.; Fardal, Mark A.; Sohn, Sangmo Tony +3 more
We present a detailed study of the internal structure and kinematics of the core of the Sagittarius dwarf spheroidal galaxy (Sgr). Using machine-learning techniques, we have combined the information provided by 3300 RR Lyrae stars, more than 2000 spectroscopically observed stars, and the Gaia second data release to derive the full phase space, i.e…