Search Publications
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…
A New Generation of Cool White Dwarf Atmosphere Models. II. A DZ Star with Collision-induced Absorption
Dufour, P.; Allard, N. F.; Blouin, S. +1 more
In the first paper of this series, we presented our upgraded cool white dwarf atmosphere code. In this second paper, we use our new models to analyze SDSS J080440.63+223948.6 (J0804+2239), the first DZ star to show collision-induced absorption (CIA). This object provides a crucial test for our models, since previous versions of our code were unabl…
ALMA 26 arcmin2 Survey of GOODS-S at One-millimeter (ASAGAO): X-Ray AGN Properties of Millimeter-selected Galaxies
Ivison, R. J.; Taniguchi, Y.; Yun, M. S. +33 more
We investigate the X-ray active galactic nucleus (AGN) properties of millimeter galaxies in the Great Observatories Origins Deep Survey South (GOODS-S) field detected with the Atacama Large Millimeter/submillimeter Array (ALMA), by utilizing the Chandra 7-Ms data, the deepest X-ray survey to date. Our millimeter galaxy sample comes from the ASAGAO…
The Origin of Double-peaked Narrow Lines in Active Galactic Nuclei. IV. Association with Galaxy Mergers
Newman, Jeffrey A.; Stemo, Aaron; Comerford, Julia M. +4 more
Double-peaked narrow emission lines in active galactic nucleus (AGN) spectra can be produced by AGN outflows, rotation, or dual AGNs, which are AGN pairs in ongoing galaxy mergers. Consequently, double-peaked narrow AGN emission lines are useful tracers of the coevolution of galaxies and their supermassive black holes, as driven by AGN feedback an…
Spectropolarimetric Inversions of the Ca II 8542 Å Line in an M-class Solar Flare
Mathioudakis, M.; Rouppe van der Voort, L.; Carlsson, M. +3 more
We study the M1.9-class solar flare SOL2015-09-27T10:40 UT using high-resolution full Stokes imaging spectropolarimetry of the Ca II 8542 Å line obtained with the CRISP imaging spectropolarimeter at the Swedish 1-m Solar Telescope. Spectropolarimetric inversions using the non-LTE code NICOLE are used to construct semiempirical models of the flarin…
Rotating Stars from Kepler Observed with Gaia DR2
Davenport, James R. A.; Covey, Kevin R.
We have matched the astrometric data from Gaia Data Release 2 to the sample of stars with measured rotation periods from Kepler. Using 30,305 stars with good distance estimates, we select 16,248 as being likely main-sequence single stars centered within a 0.5 mag region about a 1 Gyr isochrone, removing many subgiants and unresolved binary stars f…
The AGN Ionization Cones of NGC 5728. I. Excitation and Nuclear Structure
Durré, Mark; Mould, Jeremy
We explore the gas morphology and excitation mechanisms of the ionization cones of the Type II Seyfert galaxy NGC 5728. Near-IR and optical data from the SINFONI and MUSE integral field units on the Very Large Telescope are combined with Hubble Space Telescope optical images, Chandra X-ray data, and Very Large Array radio observations. The complex…
The Far-infrared Emission of the First Massive Galaxies
Shivaei, Irene; Lyu, Jianwei; Rieke, George H. +2 more
Massive Population II galaxies undergoing the first phase of vigorous star formation after the initial Population III stage should have high energy densities and silicate-rich interstellar dust. We have modeled the resulting far-infrared spectral energy distributions (SEDs), demonstrating that they are shifted substantially to bluer (“warmer”) wav…
An Evaluation of 10 Lensing Models of the Frontier Fields Cluster MACS J0416.1-2403
Sharon, K.; Mahler, G.; Remolina González, J. D.
Galaxy clusters can act as gravitational lenses and magnify the universe behind them, allowing us to see deep into the early universe. The Hubble Space Telescope Frontier Fields program uses six galaxy clusters imaged by Hubble to discover and study galaxies at z ∼ 5-10. Seven independent teams developed lens models and derived magnifications for …