Search Publications
On the Interpretation of the Ultraviolet Spectra of Symbiotic Stars and Recurrent Novae. II. The 1985 Outburst of RS Ophiuchi
Sonneborn, G.; Shore, Steven N.; Starrfield, Sumner +1 more
We discuss the 1985 outburst of the symbiotic recurrent nova RS Oph using spectra obtained with the International Ultraviolet Explorer satellite and contemporaneous ground-based optical spectra. The low- resolution integrated fluxes show that a short-lived constant bolometric luminosity phase existed in the early outburst. If this reached the Eddi…
The Intermediate-Mass Population in the Core of the R136 Star Cluster
Holtzman, Jon A.; Lynds, Roger; Groth, Edward J. +3 more
R136, the compact, luminous star cluster at the center of the 30 Doradus nebula, represents an extreme mode of star formation. Yet it is unique among these kinds of objects in that it can be resolved into individual stars and the star formation process probed through the stellar products. In a previous paper we reported on a study of the intermedi…
Cataclysmic and Close Binaries in Star Clusters. IV. The Unexpectedly Low Number of Erupting Dwarf Novae Detected by the Hubble Space Telescope in the Core of 47 Tucanae
Gilliland, Ronald L.; Saha, Abhijit; Shara, Michael M. +2 more
The standard model of tidal capture predicts that ∼45 moderately bright cataclysmic binaries should exist today in 47 Tuc. To test this prediction, we have conducted a search for erupting dwarf novae in the center of 47 Tuc with 12 separate epochs of Hubble Space Telescope (HST) images in visual through near-UV bands. We have found a second erupti…
Extended LY alpha -absorbing Halos around Nearby Galaxies
Bowen, David V.; Pettini, Max; Blades, J. Chris
In order to establish the Lyα absorption cross section of present-day galaxies, we have identified 38 galaxies with z = 0-0.08 that lie within 40-500 h^-1^ kpc of the line of sight to a QSO observed with the Faint Object Spectrograph aboard the Hubble Space Telescope (HST). Including three galaxies in the field of 3C 273 investigated by previous a…
The Nuclear Starburst Driven by a Supermassive Black Hole Binary
Wada, Keiichi; Taniguchi, Yoshiaki
We propose a new formation mechanism of the nuclear starburst and hot- spot nuclei: a supermassive black hole binary formed by a merger with a nucleated satellite galaxy triggers intense star formation in the central regions of spiral galaxies in which the nuclear gas disk has been formed already by the dynamical effect of the merger itself. As th…
Galaxy Clustering around Nearby Luminous Quasars
Schneider, Donald P.; Bahcall, John N.; Kirhakos, Sofia +1 more
We examine the clustering of galaxies around a sample of 20 luminous low redshift ( z <~ 0.30) quasars observed with the Wide Field Camera-2 on the Hubble Space Telescope (HST). The HST resolution makes possible galaxy identification brighter than V = 24.5 and as close as 1" or 2" to the quasar. We find a significant enhancement of galaxies wit…
The Intermediate Stellar Mass Population in NGC 604 Determined from Hubble Space Telescope Images
Lynds, Roger; O'Neil, Earl J., Jr.; Baum, William A. +1 more
We present photometry of stars in the giant H II region NGC 604 in M33. The photometry is measured from Hubble Space Telescope images through the F336W, F555W, and F814W broadband filters. Color-magnitude diagrams of the stars in NGC 604 show a main sequence detected down to an MF555W,0 of -1 (nearly 6 Msun). In addition, there are…
Highly Ionized Interstellar Atoms--Heated, Cooled, or Mixed?
Spitzer, Lyman, Jr.
Recent observations with the Goddard High Resolution Spectrograph on the Hubble Space Telescope, combined with Copernicus results, make possible a comparison between C+3 and O+5 interstellar column densities in both the halo and the disk of our Galaxy. The ratio N(C+3)/N(O+5) for six lines of sight in the disk is about an order of magnitude less t…
A Self-consistent Optical, Ultraviolet, and Extreme-Ultraviolet Model for the Spectrum of the Hot White Dwarf G191-B2B
Barstow, M. A.; Holberg, J. B.; Lanz, T. +1 more
The star G191-B2B is one of a number of hot DA white dwarfs whose atmospheres have been found to contain significant quantities of heavy elements, including C, N, 0, Si, Fe, and Ni. Several earlier studies have measured their abundances using IUE echelle data in conjunction with synthetic spectra derived from theoretical model atmosphere calculati…
AR Ursae Majoris: The First High-Field Magnetic Cataclysmic Variable
Gänsicke, B. T.; de Martino, D.; Szkody, Paula +5 more
We identify the luminous soft X-ray source AR UMa as a magnetic cataclysmic variable containing a white dwarf with the highest field yet detected in an accreting binary. lUE and optical spectroscopy, optical photometry, and circular polarimetry and spectropolarimetry define remarkably distinct accretion states of this binary. Circular polarization…