Search Publications
Star-galaxy classification in the Dark Energy Survey Y1 data set
Bechtol, K.; Smith, M.; Allam, S. +76 more
We perform a comparison of different approaches to star-galaxy classification using the broad-band photometric data from Year 1 of the Dark Energy Survey. This is done by performing a wide range of tests with and without external `truth' information, which can be ported to other similar data sets. We make a broad evaluation of the performance of t…
Resolving the Powerful Radio-loud Quasar at z ∼ 6
Walter, Fabian; Bañados, Eduardo; Momjian, Emmanuel +2 more
We present high angular resolution imaging (23.9 × 11.3 mas, 138.6 × 65.5 pc) of the radio-loud quasar PSO J352.4034-15.3373 at z = 5.84 with the Very Long Baseline Array (VLBA) at 1.54 GHz. This quasar has the highest radio-to-optical flux density ratio at such a redshift, making it the radio-loudest source known to date at z ∼ 6. The VLBA observ…
XZ: Deriving redshifts from X-ray spectra of obscured AGN
Bauer, F. E.; Salvato, M.; Buchner, J. +2 more
Context. Redshifts are fundamental for our understanding of extragalactic X-ray sources. Ambiguous counterpart associations, expensive optical spectroscopy, and/or multimission multiwavelength coverage to resolve degeneracies often make estimation difficult in practice.
Aims: We attempt to constrain redshifts of obscured active galactic nucle…
A 3D model of polarized dust emission in the Milky Way
Delabrouille, Jacques; Martínez-Solaeche, Ginés; Karakci, Ata
We present a three-dimensional model of polarized galactic dust emission that takes into account the variation of the dust density, spectral index and temperature along the line of sight, and contains randomly generated small-scale polarization fluctuations. The model is constrained to match observed dust emission on large scales, and match on sma…
Radio-loudness in black hole transients: evidence for an inclination effect
Motta, S. E.; Casella, P.; Fender, R. P.
Accreting stellar-mass black holes appear to populate two branches in a radio:X-ray luminosity plane. We have investigated the X-ray variability properties of a large number of black hole low-mass X-ray binaries, with the aim of unveiling the physical reasons underlying the radio-loud/radio-quiet nature of these sources, in the context of the know…
ALMA 12CO (J = 1-0) imaging of the nearby galaxy M 83: Variations in the efficiency of star formation in giant molecular clouds
Nakanishi, Hiroyuki; Kuno, Nario; Kawabe, Ryohei +6 more
We present results of the 12CO (1-0) mosaic observations of the nearby barred-spiral galaxy M 83 obtained with the Atacama Large Millimeter/submillimeter Array (ALMA). The total flux is recovered by combining the ALMA data with single-dish data obtained using the Nobeyama 45 m telescope. The combined map covers a ∼13 kpc2 fie…
Community Targets of JWST’s Early Release Science Program: Evaluation of WASP-63b
Deming, Drake; Madhusudhan, Nikku; Burrows, Adam +21 more
We present observations of WASP-63b by the Hubble Space Telescope (HST) as part of “A Preparatory Program to Identify the Single Best Transiting Exoplanet for James Webb Space Telescope (JWST) Early Release Science (ERS).” WASP-63b is one of the community targets under consideration for the JWST ERS program. We present a spectrum derived from a si…
The Cygnus Loop's distance, properties, and environment driven morphology
Blair, William P.; Raymond, John C.; Fesen, Robert A. +2 more
The Cygnus Loop is among the brightest and best studied evolved Galactic supernova remnants. However, its distance has remained uncertain thus undermining quantitative understanding about many of its fundamental properties. Here we present moderate-dispersion spectra of three stars with projected locations toward the remnant. Spectra of these star…
New Hot Subdwarf Stars Identified in Gaia DR2 with LAMOST DR5 Spectra
Zhao, Gang; Németh, Péter; Zhao, Jingkun +1 more
We selected 4593 hot subdwarf candidates from the Gaia DR2 Hertzsprung-Russell (HR) diagram. By combining the sample with Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) DR5, we identified 294 hot subdwarf stars, including 169 sdB, 63 sdOB, 31 He-sdOB, 22 sdO, 7 He-sdO, and 2 He-sdB stars. The atmospheric parameters (e.g., T
Evidence for the Existence of Abundant Intracluster Light at z = 1.24
Jee, M. James; Ko, Jongwan
Intracluster stars are believed to be unbound from their progenitor galaxies and diffused throughout the galaxy cluster, creating intracluster light (ICL). However, when and how these stars form is still under debate. To directly constrain the origin, one powerful method is to study clusters at the epoch when mature galaxy clusters began to appear…