Search Publications
HST/STIS UV Spectroscopy of Two Quiescent X-Ray Novae: A0620-00 and Centaurus X-4
Remillard, Ronald A.; McClintock, Jeffrey E.
In 1998 we made UV spectroscopic observations with HST/STIS of A0620-00 and Cen X-4, which are two X-ray novae (also known as soft X-ray transients). These binary systems are similar in all respects except that the former contains a black hole and the latter contains a neutron star. A UV spectrum (1700-3100 Å) is presented for the quiescent state …
A Uniform Analysis of Boron in F and G Disk Dwarfs fromHubble Space Telescope Archival Spectra
Cunha, Katia; Smith, Verne V.; Lambert, David L. +1 more
The boron abundance is derived for 14 near-solar metallicity F and G dwarfs from the archived data set of spectra obtained with the Hubble Space Telescope Goddard High Resolution Spectrograph in the region of the B I resonance line near 2497 Å. These abundances are derived in a uniform way with respect to recent work on solar boron. The synthetic …
Mapping Infrared Enhancements in Closely Interacting Spiral-Spiral Pairs. I. ISO CAM and ISO SWS Observations
Xu, Cong; Gao, Yu; Lu, Nanyao +3 more
Mid-infrared (MIR) imaging and spectroscopic observations are presented for a well-defined sample of eight closely interacting (CLO) pairs of spiral galaxies that have overlapping disks and show enhanced far-infrared (FIR) emission. The goal is to study the star formation distribution in CLO pairs, with special emphasis on the role of ``overlap st…
The Hubble Space Telescope Key Project on the Extragalactic Distance Scale. XXI. The Cepheid Distance to NGC 1425
Kelson, Daniel D.; Illingworth, Garth D.; Huchra, John P. +22 more
The distance to NGC 1425 has been derived from Cepheid variables, as part of the Hubble Space Telescope Key Project on the Extragalactic Distance Scale. Thirteen F555W (V) and eight F814W (I) epochs of cosmic-ray-split Wide Field Planetary Camera 2 observations were obtained. Twenty-nine Cepheids were discovered, with periods ranging from 16 to 63…
Comparison of the 1998 April 29 M6.8 and 1998 November 5 M8.4 Flares
Yang, Guo; Denker, Carsten; Wang, Haimin +6 more
We combined, and analyzed in detail, the Hα and magnetograph data from Big Bear Solar Observatory (BBSO), full-disk magnetograms from the Michelson Doppler Imager (MDI) on board Solar and Heliospheric Observatory (SOHO), coronagraph data from the Large Angle Spectrometric Coronagraph (LASCO) of SOHO, Fe XII 195 Å data from the Extreme ultraviolet …
Molecular Gas in the Powerful Radio Galaxies 3C 31 and 3C 264: Major or Minor Mergers?
Combes, Françoise; Lim, Jeremy; Leon, Stephane +1 more
We report the detection of 12CO (1-->0) and 12CO (2-->1) emission from the central regions (<~5-10 kpc) of the two powerful radio galaxies 3C 31 and 3C 264. Their individual CO emission exhibits a double-horned line profile that is characteristic of an inclined rotating disk with a central depression at the rising pa…
Interstellar and Circumstellar Optical and Ultraviolet Lines Toward SN 1998S
Bowen, David V.; Meyer, David M.; Roth, Katherine C. +1 more
We have observed SN 1998S which exploded in NGC 3877, with the Utrecht Echelle Spectrograph (6-7 km s-1 FWHM) at the William Herschel Telescope and with the E230M echelle of the Space Telescope Imaging Spectrograph (8 km s-1 FWHM) aboard the Hubble Space Telescope. Both data sets were obtained at two epochs, separated by 19 (…
The Globular Cluster Systems in the Coma Ellipticals. I. The Luminosity Function in NGC 4874 and Implications for Hubble's Constant
Kavelaars, J. J.; Harris, William E.; Hesser, James E. +2 more
We have used deep Hubble Space Telescope WFPC2 images in V (F606W) and I (F814W) to measure the luminosity distribution of the globular clusters in NGC 4874, the central cD galaxy of the Coma cluster. We find the ``turnover'' point of the globular cluster luminosity function (GCLF) to lie at V=27.88+/-0.12, while the overall GCLF shape matches the…
Observations of a Possible New Soft Gamma Repeater, SGR 1801-23
Cline, T.; Hurley, K.; Kouveliotou, C. +4 more
We report on two 1997 June observations of a soft bursting source whose time histories and energy spectra are consistent with those of the soft gamma repeaters. The source can be localized only to an ~3.8d long error box in the direction of the Galactic center, whose area is ~80 arcmin2. The location of the source, while not consistent …
The Late Afterglow and Host Galaxy of GRB 990712
Hjorth, Jens; Courbin, Frederic; Holland, Stephen +3 more
We present deep Hubble Space Telescope (HST) imaging, as well as ground-based imaging and spectroscopy, of the optical afterglow associated with the long-duration gamma-ray burst GRB 990712 and its host galaxy. The data were obtained 48-123 days after the burst occurred. The magnitudes of the host (R=21.9, V=22.5) and optical afterglow (R=25.4, V=…