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The Optical and Ultraviolet Spectral Energy Distributions of Short-Period Black Hole X-Ray Transients in Outburst
Hynes, R. I.
We compile optical and UV spectra of a sample of ``typical'' short-period black hole X-ray transients in outburst. We also survey determinations of interstellar extinction and distance to deredden spectra and compare absolute fluxes. Hence, we perform a comparative study of the broadband spectral energy distributions (SEDs). We find that, given su…
The Stellar Populations in the Central Parsecs of Galactic Bulges
Filippenko, Alexei V.; Ho, Luis C.; Shields, Joseph C. +5 more
We present Hubble Space Telescope blue spectra at intermediate spectral resolution for the nuclei of 23 nearby disk galaxies. These objects were selected to have nebular emission in their nuclei and span a range of emission-line classifications, as well as Hubble types. In this paper we focus on the stellar population as revealed by the continuum …
The White Dwarf Cooling Sequence in NGC 6791
Anderson, Jay; Salaris, Maurizio; Bedin, Luigi R. +4 more
In the old, populous, and metal-rich open cluster NGC 6791, we have used deep Hubble Space Telescope Advanced Camera for Surveys images to track the white dwarf cooling sequence down to mF606W~=28.5. The white dwarf luminosity function shows a well-defined peak at mF606W~=27.4 and a bending to the blue in the color-magnitude …
GRB 020410: A Gamma-Ray Burst Afterglow Discovered by Its Supernova Light
Garnavich, Peter; Tanvir, Nial; Hjorth, Jens +19 more
We present the discovery and monitoring of the optical transient (OT) associated with GRB 020410. The fading OT was found by Hubble Space Telescope (HST) observations taken 28 and 65 days after burst at a position consistent with the X-ray afterglow, making this the first time that the optical afterglow of a gamma-ray burst (GRB) has been discover…
A Remarkable Low-Mass X-Ray Binary within 0.1 Parsecs of the Galactic Center
Brandt, W. N.; Ghez, A. M.; Muno, M. P. +5 more
Recent X-ray and radio observations by Muno et al. and Bower et al. have identified a transient low-mass X-ray binary (LMXB) located only 0.1 pc in projection from the Galactic center, CXOGC J174540.0-290031. In this paper, we report the detailed analysis of X-ray and infrared observations of the transient and its surroundings. Chandra observation…
Cloud Structure and Physical Conditions in Star-forming Regions from Optical Observations. II. Analysis
Andersson, B. -G.; Federman, S. R.; Sheffer, Y. +1 more
To complement the optical absorption line survey of diffuse molecular gas in Paper I, we obtained and analyzed far-ultraviolet H2 and CO data on lines of sight toward stars in Cep OB2 and Cep OB3. Possible correlations between column densities of different species for individual velocity components, not total columns along a line of sig…
Discovery of a Nearly Edge-on Disk around HD 32297
Schneider, Glenn; Hines, Dean C.; Silverstone, Murray D.
We report the discovery of a nearly edge-on disk about the A0 star HD 32297 seen in light scattered by the disk grains revealed in NICMOS PSF-subtracted coronagraphic images. The disk extends to a distance of at least 400 AU (3.3") along its major axis with a 1.1 µm flux density of 4.81 +/- 0.57 mJy beyond a radius of 0.3" from the coronagra…
XMM-Newton Observations of Evolution of Cluster X-Ray Scaling Relations at z=0.4-0.7
Vikhlinin, A.; Kotov, O.
We present a spatially resolved analysis of the temperature and gas density profiles of galaxy clusters at z=0.4-0.7 observed with XMM-Newton. These data are used to derive the total cluster mass within the radius r500 without assuming isothermality and also to measure the average temperature and total X-ray luminosity, excluding the co…
Identifying Lenses with Small-Scale Structure. II. Fold Lenses
Keeton, Charles R.; Gaudi, B. Scott; Petters, A. O.
When the source in a four-image gravitational lens system lies sufficiently close to a ``fold'' caustic, two of the lensed images lie very close together. If the lens potential is smooth on the scale of the separation between the two close images, the difference between their fluxes should approximately vanish, Rfold≡(F+-F
Observations of Separator Reconnection to an Emerging Active Region
Longcope, D. W.; Scott, J.; McKenzie, D. E. +1 more
Extreme-ultraviolet (EUV) observations of an emerging active region are used to study separator reconnection in the corona. We identify each EUV loop connecting the emerging polarity to a nearby existing active region over the 41 hr period beginning at emergence onset. Their geometrical resemblance to post-reconnection field lines from a magnetic …