Search Publications
The X-Ray Binary-star Cluster Connection in Late-type Galaxies
Chandar, Rupali; Maccarone, Thomas J.; Thilker, David A. +3 more
We conduct one of the largest systematic investigations of bright X-ray binaries (XRBs) in both young star clusters and ancient globular clusters (GCs) using a sample of six nearby star-forming galaxies. Combining complete CXO X-ray source catalogs with optical Physics at High Angular Resolution in Nearby Galaxies-Hubble Space Telescope cluster ca…
Environmental Impacts on the Rest-frame UV Size and Morphology of Star-forming Galaxies at z 2
Koyama, Yusei; Kodama, Tadayuki; Shimakawa, Rhythm +1 more
We report the measurement of rest-frame UV size and morphology of Hα-emission-selected star-forming galaxies (HAEs) in four protoclusters at z ~ 2 (PKS 1138-262, USS 1558-003, PHz G237.0+42.5, and CC 2.2) using archival Hubble Space Telescope Advanced Camera Survey (HST/ACS) F814W data. We compare the measurement of 122 HAEs in protoclusters detec…
Multiwavelength Characterization of the High-mass X-Ray Binary Population of M33
Williams, Benjamin F.; Eracleous, Michael; Dalcanton, Julianne J. +12 more
We present multiwavelength characterization of 65 high-mass X-ray binary (HMXB) candidates in M33. We use the Chandra ACIS survey of M33 (ChASeM33) catalog to select hard X-ray point sources that are spatially coincident with UV-bright point-source optical counterparts in the Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region catal…
A New Physical Picture for Active Galactic Nuclei Lacking Optical Emission Lines
Ellison, Sara L.; Faber, S. M.; Salim, Samir +2 more
In this work, we use ~500 low-redshift (z ~ 0.1) X-ray active galactic nuclei (AGNs) observed by XMM-Newton and the Sloan Digital Sky Survey (SDSS) to investigate the prevalence and nature of AGNs that apparently lack optical emission lines ("optically dull AGNs"). Although one quarter of spectra appear absorption-line dominated in visual assessme…
Mass Distribution for Single-lined Hot Subdwarf Stars in LAMOST
Németh, Péter; Yang, Yong; Zhao, Jingkun +4 more
Masses for 664 single-lined hot subdwarf stars identified in LAMOST were calculated by comparing synthetic fluxes from spectral energy distribution with observed fluxes from a Virtual Observatory service. Three groups of hot subdwarf stars were selected from the whole sample according to their parallax precision to study the mass distributions. We…
The Radio Parallax of the Crab Pulsar: A First VLBI Measurement Calibrated with Giant Pulses
Deller, Adam T.; Kirsten, Franz; van Kerkwijk, Marten H. +2 more
We use four observations with the European very long baseline interferometry (VLBI) network to measure the first precise radio parallax of the Crab Pulsar. We found two in-beam extragalactic sources just outside the Crab Nebula, with one bright enough to use as a background reference source in our data. We use the Crab Pulsar's giant pulses to det…
Understanding the Deflection of the "Cartwheel CME": Data Analysis and Modeling
Vourlidas, Angelos; Balmaceda, Laura A.; Cécere, Mariana +1 more
We study the low corona evolution of the "Cartwheel" coronal mass ejection (CME; 2008 April 9) by reconstructing its three-dimensional path and modeling it with magnetohydrodynamic simulations. This event exhibited a double deflection that has been reported and analyzed in previous works but whose underlying cause remained unclear. The Cartwheel C…
A New Sample of Transient Ultraluminous X-Ray Sources Serendipitously Discovered by Swift/XRT
Fürst, Felix; Middleton, Matthew J.; Walton, Dominic J. +11 more
Ultraluminous X-ray sources (ULXs) are our best laboratories for studying extreme super-Eddington accretion. Most studies of these objects are of relatively persistent sources; however, there is growing evidence to suggest a large fraction of these sources are transient. Here we present a sample of five newly reported transient ULXs in the galaxie…
The S-Web Origin of Composition Enhancement in the Slow-to-moderate Speed Solar Wind
Sun, X.; Lynch, B. J.; Lepri, S. T. +3 more
Connecting the solar wind observed throughout the heliosphere to its origins in the solar corona is one of the central aims of heliophysics. The variability in the magnetic field, bulk plasma, and heavy ion composition properties of the slow wind are thought to result from magnetic reconnection processes in the solar corona. We identify regions of…
Solar Radio Spikes and Type IIIb Striae Manifestations of Subsecond Electron Acceleration Triggered by a Coronal Mass Ejection
Kontar, Eduard P.; Vilmer, Nicole; Chen, Xingyao +3 more
Understanding electron acceleration associated with magnetic energy release at subsecond scales presents major challenges in solar physics. Solar radio spikes observed as subsecond, narrow-bandwidth bursts with Δf/f ~ 10-3-10-2 are indicative of a subsecond evolution of the electron distribution. We present a statistical anal…