Search Publications
EXOSAT Observations of the Low-Luminosity X-Ray Burster 4U 0614+091: Evidence for a Hard Power-Law Tail
Barret, Didier; Grindlay, Jonathan E.
We have analyzed archival EXOSAT observations of 4U 0614+091 as recorded by the Medium Energy experiment (2-10 keV). The data set consists of five spectra, all associated with low X-ray luminosities (L(X,1-20 keV) ≤ 2 × 1036 ergs s-1, d = 2 kpc). The spectrum corresponding to the highest intensity state (FX
The Discovery of a Jetlike Feature from the Massive Star Herschel 36
Henning, T.; Stecklum, B.; Eckart, A. +2 more
The O7 V star Hershcel 36 has been studied in the near-infrared by ground-based high-resolution techniques. These observations and image restoration of Hubble Space Telescope (HST) planetary camera hydrogen alpha and (S II) images led to the detection of a jetlike feature. The interpretation of that feature as a jet is discussed in relation to a c…
The Ultraviolet Reflectivity of Jupiter at 3.5 Angstrom Resolution from Astro-1 and Astro-2
Wolven, Brian C.; Feldman, Paul D.; McGrath, Melissa A. +2 more
The reflectivity of Jupiter in the wavelength band from 1450 to 1850 A at 3.5 A resolution has been determined from measurements of Jovian equatorial spectra obtained by the Hopkins Ultraviolet Telescope, which was flown on the Space Shuttle Columbia during the 1990 December Astro-1 mission and then on the Endeavour during the 1995 March Astro-2 m…
A Search for a Pulsar in the Remnant of SN 1987A with the Hubble Space Telescope High-Speed Photometer
Dolan, J. F.; Boyd, P. T.; Nelson, M. J. +8 more
The High Speed Photometer (HSP) on the Hubble Space Telescope (HST) observed the remnant of SN 1987A on four different epochs between 1992 June 2 and 1993 November 4 in a 1600-7000 Å bandpass. Each observation was ∼40 minutes in duration and used a 100 microseconds sampling time. Assuming a spectrum like PSR B0540 -69 with similar reddening, the o…
Generation of Mass Loss in K Giants: The Failure of Global Oscillation Modes and Possible Implications
Cuntz, M.; Sutmann, G.
It is a well-established observational result that many inactive K stars show global oscillation modes, which lead to low-amplitude photospheric velocity variations. It is the purpose of this paper to investigate whether these modes are relevant to the outer atmospheric dynamics, including the generation of mass loss. We find that this is not the …
Ultraviolet Extinction to 10.8 Inverse Microns
Aannestad, Per A.
UV extinction curves that represent observed variations i diffuse clouds (Zeta Oph, Xi Per, and Sigma Sco) have been derived by combining IUE and Voyager data and have been modeled by a multicomponent size distribution of silicate and carbonaceous giants. We have used theoretical model atmospheres as our reddening-free standards, and, in the case …
A Reanalysis of the SWP-HI IUE Observations of Capella
Wood, Brian E.; Ayres, T. R.
We have reanalyzed the numerous high-resolution, far-ultraviolet observations of Capella made by the International Ultraviolet Explorer (IUE) in its 16 yr lifetime. Our purpose was to search for long-term profile variations in Capella's ultraviolet emission lines and to complement the analysis of Goddard High Resolution Spectrograph (GHRS) observa…
Resolution of Massive Compact Clusters in the 30 Doradus Periphery with the Hubble Space Telescope
Walborn, Nolan R.; Parker, Joel Wm.; White, Richard L. +2 more
Hubble Space Telescope Wide Field/Planetary Camera UBV images of three massive, compact multiple systems with the SNR 30 Dor B/NGC 2060 and 30 Dor C/NGC 2044 are discussed and illustrated. In two cases, WN+OB objects have been resolved into additional components to those previously known from ground-based observations, substantially reducing the l…
Hubble Space Telescope Imaging of a Radio-quiet Galaxy at Redshift Z = 3.4
Giavalisco, M.; Macchetto, F. D.; Sparks, W. B. +1 more
We have observed with the Wide Field/Planetary Camera (WF/PC) on the Hubble Space Telescope (HST) a radio-quiet Lyα-emitting galaxy at redshift z = 3.428 (G2 below). The images probe the rest-frame UV light around 1250 A with an angular resolution of ~0.1", corresponding to 1.4 h_50_^-1^ kpc at redshift z = 3.4 (in this Letter we use q_0_ = 0 and …
Eclipse Timings of the Low-Mass X-Ray Binary EXO 0748-676: Statistical Arguments against Orbital Period Changes
Wood, Kent S.; Hertz, Paul; Cominsky, Lynn
EXO 0748-676, an eclipsing low-mass X-ray binary, is one of only about four or five low-mass X-ray binaries for which orbital period evolution has been reported. We observed a single eclipse egress with ROSAT . The time of this egress is consistent with the apparent increase in Porb previously reported on the basis of EXOSAT and Ginga o…