Search Publications
Hubble Space Telescope Identification of the Optical Counterparts of Ultraluminous X-Ray Sources in M51
Terashima, Yuichi; Wilson, Andrew S.; Inoue, Hirohiko
We present the results of a search for optical identifications of ultraluminous X-ray sources (ULXs) in M51 by using mosaic images taken with the Hubble Space Telescope(HST) Advanced Camera for Surveys (ASC) in filters F435W (B), F555W (V), F814W (I), and F658N (Hα). Our sample, consisting of nine ULXs, is defined by analyzing the three Chandra ob…
Enceladus: A Source of Nitrogen and an Explanation for the Water Vapor Plume Observed by Cassini
Loeffler, M. J.; Raut, U.; Baragiola, R. A.
Recently, the Cassini spacecraft observed an unexpected emission of plumes of water vapor, nitrogen, and icy particles from the southern polar region of Saturn's icy moon Enceladus. While these findings support previous ideas of geological activity in this icy moon, there is no experimental evidence explaining how these plumes could be produced at…
The Soft X-Ray Blast in the Apparently Subluminous GRB 031203
Foley, S.; Watson, D.; Fynbo, J. P. U. +11 more
GRB 031203 was a very low apparent luminosity γ-ray burst (GRB). Coincidentally, it was also the first GRB with a dust-scattered X-ray halo. The observation of the halo allowed us to infer the presence of a large soft X-ray fluence in the total burst output. It has also been claimed, however, that GRB 031203 was intrinsically subenergetic, represe…
The Jet and Circumnuclear Environment of 3C 293
O'Dea, Christopher P.; Axon, David J.; Sparks, William B. +5 more
We present new HST NIR polarimetry, broadband and narrowband imaging, and MERLIN 4.5 GHz multifrequency synthesis radio imaging of 3C 293, a unique radio galaxy whose host is an obvious merger remnant, in an exceptionally underdense region of space. We have discovered NIR, optical, and UV synchrotron emission from the jet. In the optical, the jet …
Oxygen Abundances in the Milky Way Using X-Ray Absorption Measurements toward Galaxy Clusters
Mushotzky, R. F.; Baumgartner, W. H.
We present measurements of the oxygen abundance of the Milky Way's ISM by observing the K-shell X-ray photoionization edge toward galaxy clusters. This effect is most easily observed toward objects with Galactic columns (nH) of a few times 1021 cm-2. We measure X-ray column densities toward 11 clusters and find tha…
Coronal Emission Measures and Abundances for Moderately Active K Dwarfs Observed by Chandra
Wood, Brian E.; Linsky, Jeffrey L.
We have used Chandra to resolve the nearby 70 Oph (K0 V+K5 V) and 36 Oph (K1 V+K1 V) binary systems for the first time in X-rays. The LETG/HRC-S spectra of all four of these stars are presented and compared with an archival LETG spectrum of another moderately active K dwarf, ɛ Eri. Coronal densities are estimated from O VII line ratios and emissio…
Chemical Enrichment of the Complex Hot ISM of the Antennae Galaxies. II. Physical Properties of the Hot Gas and Supernova Feedback
Zezas, A.; Raymond, J. C.; King, A. R. +5 more
We investigate the physical properties of the interstellar medium (ISM) in the merging pair of galaxies known as the Antennae (NGC 4038/4039), using the deep co-added ~411 ks Chandra ACIS-S data set. The method of analysis and some of the main results from the spectral analysis, such as metal abundances and their variations from ~0.2 to ~20-30 tim…
The Magnetic Field Strength in the Wall of the Local Bubble toward l, b ~ 300°, 0°
Andersson, B. -G.; Potter, S. B.
We present polarization measurements in the region around l, b = 300°, 0°, toward stars with well-determined distances, primarily in the range 40-200 pc. We argue that these observations trace polarization caused by dust in the wall of the Local Bubble (LB). Using a Chandrasekhar-Fermi analysis, we derive a plane-of-the-sky magnetic field strength…
Chandra and Hubble Space Telescope Study of the Globular Cluster NGC 288
Anderson, Scott F.; Kong, Albert K. H.; Verbunt, Frank +5 more
We report on the Chandra X-Ray Observatory observations of the globular cluster NGC 288. We detect four X-ray sources within the core radius and seven additional sources within the half-mass radius down to a limiting luminosity of LX=7×1030 ergs s-1 (assuming cluster membership) in the 0.3-7 keV band. We also obser…
Observations of Flux Rope Formation in the Outer Corona
Sheeley, N. R., Jr.; Wang, Y. -M.
In previous studies employing the Large Angle and Spectrometric Coronagraph (LASCO), we identified a class of white-light ejections that separate into incoming and outgoing components at distances of ~3-5 Rsolar from Sun center. These events, of which up to several per month are observed during high solar activity, are generally precede…