Search Publications
Probing the Innermost Ejecta Layers in Supernova Remnant Kes 75: Implications for the Supernova Progenitor
Gelfand, Joseph D.; Temim, Tea; Koo, Bon-Chul +3 more
Supernova remnants (SNRs) that contain pulsar wind nebulae (PWNe) are characterized by distinct evolutionary stages. In very young systems, the PWN drives a shock into the innermost supernova (SN) material, giving rise to low-excitation lines and an infrared (IR) continuum from heated dust grains. These observational signatures make it possible to…
Exceptional Extended Field-of-view Observations by PROBA2/SWAP on 2017 April 1 and 3
West, Matthew J.; Mierla, Marilena; D'Huys, Elke +2 more
On 2017 April 1 and 3, two large eruptions on the western solar limb, which were associated with M4.4- and M5.8-class flares, respectively, were observed with the Sun Watcher with Active Pixels and Image Processing (SWAP) Extreme Ultraviolet (EUV) solar telescope on board the Project for On Board Autonomy 2 (PROBA2) spacecraft. The large field-of-…
Broadband X-Ray Spectral and Timing Analyses of the Black Hole Binary Candidate Swift J1658.2-4242: Rapid Flux Variation and the Turn-on of a Transient QPO
Gandhi, Poshak; Walton, Dominic J.; Miller, Jon M. +6 more
We report results from joint Nuclear Spectroscopic Telescope Array, Swift, and XMM-Newton observations of the newly discovered black hole X-ray binary candidate Swift J1658.2-4242 in the intermediate state. We observe a peculiar event in this source, with its X-ray flux rapidly decreasing by ∼45% in ∼40 s, accompanied by only subtle changes in the…
Forming One of the Most Massive Objects in the Universe: The Quadruple Merger in Abell 1758
O'Sullivan, E.; David, L.; Schellenberger, G. +2 more
The system A1758 is made up of two galaxy clusters, a more massive, northern cluster and a southern cluster. Both parts are undergoing major merger events at different stages. Although the mass of the merger constituents provides enough energy to produce visible shock fronts in the X-ray, none have been found to date. We present detailed temperatu…
Developing the Physical Understanding of Intermediate Polars: An X-Ray Study of TV Col and V2731 Oph
Mukai, K.; Lopes de Oliveira, R.
The X-rays in intermediate polars (IPs) originate in a compact region near the surface of a magnetic white dwarf (WD) and interact with the complex environment surrounding the emission region. Here we report a case study of two IPs, TV Col and V2731 Oph, with selected archival X-ray observations (NuSTAR, Swift, Suzaku, and XMM-Newton). For TV Col,…
Revealing a Highly Dynamic Cluster Core in Abell 1664 with Chandra
Baum, Stefi A.; O'Dea, Christopher P.; McNamara, Brian R. +11 more
We present new, deep (245 ks) Chandra observations of the galaxy cluster Abell 1664 (z = 0.1283). These images reveal rich structure, including elongation and accompanying compressions of the X-ray isophotes in the NE-SW direction, suggesting that the hot gas is sloshing in the gravitational potential. This sloshing has resulted in cold fronts, at…
High-drag Interstellar Objects and Galactic Dynamical Streams
Eubanks, T. M.
The nature of 1I/’Oumuamua (henceforth, 1I), the first interstellar object (ISO) known to pass through the solar system, remains mysterious. Feng & Jones noted that the incoming 1I velocity vector “at infinity” ({v}∞ ) is close to the motion of the Pleiades dynamical stream (or Local Association), and suggested that 1I is a young ob…
Properties of the Interstellar Medium along Sight Lines to Nearby Planet-hosting Stars
Redfield, Seth; Wood, Brian E.; Linsky, Jeffrey L. +2 more
We analyze the high-resolution ultraviolet spectra of three nearby exoplanet host stars (HD 192310, HD 9826, and HD 206860) to study interstellar properties along their lines of sight and to search for the presence of astrospheric absorption. Using the Hubble Space Telescope/Space Telescope Imaging Spectrograph spectra of the Lyα, Mg II, and Fe II…
The Fe Line Flux Ratio as a Diagnostic of the Maximum Temperature and the White Dwarf Mass of Cataclysmic Variables
Xu, Xiao-jie; Yu, Zhuo-li; Li, Xiang-dong
The flux ratio of Fe XXVI-Lyα to Fe XXV-Heα lines (I 7.0/I 6.7) is a sensitive indicator of the maximum temperature (T max), and therefore the mass of white dwarf stars (M WD) in cataclysmic variables (CVs). To examine and calibrate the theoretical I 7.0/I 6.7-T max-M
A Versatile and Accurate Method for Halo Mass Determination from Phase-space Distribution of Satellite Galaxies
Wang, Wenting; Han, Jiaxin; Li, Zhao-Zhou +2 more
We propose a versatile and accurate method to estimate the halo mass and concentration from the kinematics of satellite galaxies. We construct the 6D phase-space distribution function of satellites from a cosmological simulation based on the similarity of internal dynamics for different halos. Within the Bayesian statistical framework, not only ca…