Search Publications
The Low Quiescent X-Ray Luminosity of the Transient X-Ray Burster EXO 1747-214
Kaaret, Philip; Gelino, Dawn M.; Tomsick, John A.
We report on X-ray and optical observations of the X-ray burster EXO 1747-214. This source is an X-ray transient, and its only known outburst was observed in 1984-1985 by the EXOSAT satellite. We reanalyzed the EXOSAT data to derive the source position, column density, and a distance upper limit using its peak X-ray burst flux. We observed the EXO…
Far-Ultraviolet Spectroscopy of the Dwarf Novae SS Cygni and WX Hydri in Quiescence
Blair, William P.; Kallman, Timothy R.; Long, Knox S. +3 more
We present time-resolved FUV spectra of the dwarf novae SS Cyg and WX Hyi in quiescence from observations using the Hopkins Ultraviolet Telescope on the Astro-1 and Astro-2 space shuttle missions and the Goddard High Resolution Spectrograph on the Hubble Space Telescope. Both dwarf novae are characterized by blue continua that extend to the Lyman …
Bulk Comptonization of the Cosmic Microwave Background by Extragalactic Jets as a Probe of Their Matter Content
Georganopoulos, Markos; Kazanas, Demosthenes; Perlman, Eric +1 more
We propose a method for estimating the composition, i.e., the relative amounts of leptons and protons, of extragalactic jets that exhibit X-ray-bright knots in their kiloparsec-scale jets. The method relies on measuring, or setting upper limits on, the component of the cosmic microwave background (CMB) radiation that is bulk Comptonized (BC) by co…
Search for 17 µm H2 Pure Rotational Emission from Circumstellar Disks
Onaka, T.; Kataza, H.; Sako, S. +5 more
We report the negative detection of the S(1) pure rotational line emission of molecular hydrogen at 17.035 µm for four young stars, HD 163296, MWC 863, CQ Tau, and LkCa 15, for which Infrared Space Observatory (ISO) observations detected the S(1) emission, with the Cooled Mid-Infrared Camera and Spectrometer (COMICS) on the 8.2 m Subaru Tele…
Study of Hα Macrospicules in Coronal Holes: Magnetic Structure and Evolution in Relation to Photospheric Magnetic Setting
Wang, H.; Moore, R. L.; Jiang, Y. +2 more
Small-scale solar dynamic events such as spicules, macrospicules, and microflares may play an important role in the coronal heating and solar wind acceleration in coronal holes. In these regions, the network fields concentrated along edges of supergranules are probably the source of the fine-scale activity that may drive the heating and accelerati…
State Transition and Flaring Activity of IGR J17464-3213/H1743-322 with INTEGRAL SPI
Capitanio, F.; Ubertini, P.; Malzac, J. +4 more
IGR J17464-3213, already known as the HEAO 1 transient source H1743-322, has been detected during a state transition by INTEGRAL SPI. We describe the spectral evolution and flaring activity of IGR J17464-3213/H1743-322 from 2003 March 21 to 2003 April 22. During the first part, the source followed a continuous spectral softening, with the peak of …
The Discovery of Oxygen Kα X-Ray Emission from the Rings of Saturn
Bhardwaj, Anil; Gladstone, G. Randall; Cravens, Thomas E. +3 more
Using the Advanced CCD Imaging Spectrometer (ACIS), the Chandra X-Ray Observatory observed the Saturnian system for one rotation of the planet (~37 ks) on 2004 January 20 and again on January 26-27. In this Letter we report the detection of X-ray emission from the rings of Saturn. The X-ray spectrum from the rings is dominated by emission in a nar…
The Nature of Blue Cores in Spheroids: A Possible Connection with Active Galactic Nuclei and Star Formation
Illingworth, Garth D.; Frye, Brenda; Infante, Leopoldo +9 more
We investigate the physical nature of blue cores in early-type galaxies through the first multiwavelength analysis of a serendipitously discovered field blue-nucleated spheroid in the background of the deep Hubble Space Telescope ACS/WFC griz multicolor observations of the cluster A1689. The resolved g-r, r-i, and i-z color maps reveal a prominent…
Discovery of Strong Lensing by an Elliptical Galaxy at z = 0.0345
Tonry, John; Blakeslee, John P.; Lucey, John R. +1 more
We have discovered strong gravitational lensing by the galaxy ESO 325-G004, in images obtained with the Advanced Camera for Surveys on the Hubble Space Telescope. The lens galaxy is a boxy group-dominant elliptical at z=0.0345, making this the closest known galaxy-scale lensing system. The lensed object is very blue (B-IC~1.1), and form…
All Coronal Loops Are the Same: Evidence to the Contrary
Schmelz, J. T.; Beene, J. E.; Nasraoui, K. +3 more
The 1998 April 20 spectral line data from the Coronal Diagnostic Spectrometer on the Solar and Heliospheric Observatory show a coronal loop on the solar limb. Our original analysis of these data showed that the plasma was multithermal, both along the length of the loop and along the line of sight. However, more recent results by other authors indi…