Search Publications
Stellar Photometry in the Inner Bulge of M31 Using the Hubble Space Telescope Wide Field Camera
Rich, R. M.; Mighell, K. J.
We present photometry of two fields in the M31 bulge imaged with the Hubble Space Telescope (HST) Wide-Field Camera. The nuclear field (r <40" = 150 pc) giant branch extends to I = 19.5, M_I_ = - 5 (Cousins system), a full 0.9 mag brighter than the giant-branch tips of metal-poor Galactic globular clusters and M31 halo fields. This is also ~1.5…
New Observations with the HST Goddard High Resolution Spectrograph of the Low-Redshift Lyman-Alpha Clouds in the 3C 273 Line of Sight
Rauch, Michael; Williams, Robert; Morris, Simon +2 more
We present spectra of 3C 273 between 1216 and 1250 A obtained in the (pre-COSTAR [Corrective Optics Space Telescope Axial Replacement instrument]) configuration of the GHRS, taken with the G160M grating, with a resolution of ~20 km s^-1^. The two strong Lyα lines at velocities of ~1000 and ~1600 km s^-1^ are well fitted with Voigt profiles and yie…
The Distribution of Metal-absorbing High-Velocity Clouds in the Galaxy
Bowen, David V.; Pettini, Max; Blades, J. Chris
We present Hubble Space Telescope (HST) GHRS spectra of Mg II absorption from our own Galaxy toward seven extragalactic background sources. Along four sight lines, the bulk of the absorption occurs at velocities consistent with those expected for halo gas corotating with the disk of the Galaxy. In the other three directions the line profiles exten…
A Semiempirical Determination of the Wind Velocity Structure for the Hybrid-Chromosphere Star alpha Trianguli Australis
Ayres, Thomas R.; Harper, Graham M.; Bennett, Philip D. +3 more
We have used the Goddard High-Resolution Spectrograph (GHRS) on the Hubble Space Telescope to study the wind of the hybrid-chromosphere star α TrA (K4 II). The stellar wind produces significant absorption at negative radial velocities in the chromospheric Mg II resonance lines (h and k). Spectra obtained with the GHRS echelle high-resolution grati…
HST/GHRS Observations of the Interplanetary Medium Downwind and in the Inner Solar System
Bertaux, Jean-Loup; Clarke, John T.; Lallement, Rosine +1 more
We present high dispersion spectra of the interplanetary medium (1PM) hydrogen Lyα emission along lines of sight to infinity and to Mars, obtained with the Hubble Space Telescope (HST) and Goddard High Resolution Spectrograph (GHRS) in 1991 May, including a detailed description of the data analysis procedures. The observed 1PM emission at 46° from…
Interstellar Lead
York, D. G.; Welty, D. E.; Lauroesch, J. T. +2 more
The spectrum of 1 Sco has been recorded in the region of the 1434 A line of Pb II at S/N = 220, using the ECH-A mode of the HST/GHRS. Absorption by interstellar Pb II is seen with an equivalent width W lambda = 0.3 +/- 0.2 (2 sigma ) mA, at a radial velocity which agrees satisfactorily with that of the strongest component of the interstellar Na I …
Gas near the Center of 30 Doradus As Revealed by Hubble Space Telescope Images
Lynds, Roger; Groth, Edward J.; O'Neil, Earl J., Jr. +4 more
We present images of a 40 pc region of the 30 Doradus nebula centered about 1 arcminute north of the luminous star cluster R136 in the Large Magellanic Cloud. The region was imaged with the Hubble Space Telescope Wide Field Camera through Hα, [S II], and stellar continuum filters. These data allow us to examine this region of star formation and th…
Time-dependent Behavior and Physical Conditions of the LMC Planetary Nebula N66
Pena, M.; Torres-Peimbert, S.; Ruiz, M. T. +2 more
Optical and UV spectrophotometric data for the planetary nebula N66 in the Large Magellanic Cloud gathered in the 1987-1994 interval are analyzed. The central star, which had a featureless weak continuum, has developed intense W-R features and P Cygni profiles that were not present before 1990. He- and N-rich material, processed during the CNO cyc…
The Binary Double-degenerate Nature of the Bright DAO White Dwarf Feige 55
Barstow, M. A.; Holberg, J. B.; Saffer, Rex A. +1 more
Recent IUE and optical spectra of the bright DAO white dwarf Feige 55 reveal large Doppler shifts due to orbital motion. These Doppler shifts have a period of 1.49303 +/- 0.00011 days with a semi-amplitude of 77.4 +/- 7.0 km s-1. There is no strong photometric signature of any companion; J- and K-band photometry place an upper limit of 0.1 M⊙ on t…
Burstlike Events in the Z Source Cygnus X-2
van Paradijs, J.; van der Klis, M.; Kuulkers, E.
We have found nine burstlike events in EXOSAT data of the Z source Cyg X-2. Their durations are of the order of several seconds. Within the limited counting statistics we cannot find an indication for cooling during the burstlike events, which would have indicated that they are bona fide type I bursts, i.e., thermonuclear flashes on the surface of…