Search Publications
The Recent Growth History of the Fornax Cluster Derived from Simultaneous Sloshing and Gas Stripping: Simulating the Infall of NGC 1404
Churazov, Eugene; Jones, Christine; Nulsen, Paul E. J. +7 more
We derive the recent growth history of the Fornax Cluster, in particular the recent infall of the giant elliptical galaxy NGC 1404. We show, using a simple cluster minor merger simulation tailored to Fornax and NGC 1404, that a second or more likely third encounter between the two reproduces all the main merger features observed in both objects; w…
Optical-Mid-infrared Period-Luminosity Relations for W UMa-type Contact Binaries Based on Gaia DR 1: 8% Distance Accuracy
Wang, Shu; Deng, Licai; de Grijs, Richard +2 more
W Ursa Majoris (W UMa)-type contact binary systems (CBs) are useful statistical distance indicators because of their large numbers. Here, we establish (orbital) period-luminosity relations (PLRs) in 12 optical to mid-infrared bands (GBVRIJHK s W1W2W3W4) based on 183 nearby W UMa-type CBs with accurate Tycho-Gaia parallaxes. The 1σ dispe…
Interplanetary Type II Radio Bursts from Wind/WAVES and Sustained Gamma-Ray Emission from Fermi/LAT: Evidence for Shock Source
Gopalswamy, Nat; Akiyama, Sachiko; Yashiro, Seiji +4 more
We present quantitative evidence that interplanetary type II radio bursts and sustained gamma-ray emission (SGRE) events from the Sun are closely related. Out of about 30 SGRE events reported in Share et al. we consider 13 events that had a duration exceeding ∼5 hr to exclude any flare-impulsive phase gamma-rays. The SGRE duration also has a linea…
Volans-Carina: A New 90 Myr Old Stellar Association at 85 pc
Faherty, Jacqueline K.; Gagné, Jonathan; Mamajek, Eric E.
We present a characterization of the new Volans-Carina Association (VCA) of stars near the Galactic plane (b ≃ -10°) at a distance of ≃75-100 pc, previously identified as group 30 by Oh et al. We compile a list of 19 likely members from Gaia DR2 with spectral types B8-M2, and 46 additional candidate members from Gaia DR2, 2MASS, and AllWISE with s…
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…
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…