Search Publications
Cosmic-Ray 26Al and Its Decay in the Galaxy
Simpson, J. A.; Connell, J. J.
Radioactive 26Al (τ1/2=8.7×105 yr) has been resolved from stable 27Al in the cosmic radiation for the first time using the high mass resolution, charged particle telescope on the Ulysses spacecraft. The average density of the interstellar medium through which the cosmic radiation propagates was determine…
Infrared Emission-Line Galaxies Associated with Dampened Ly alpha and Strong Metal Absorber Redshifts
Thompson, D.; Mannucci, F.; Williger, G. M. +1 more
Eighteen candidates for emission-line galaxies were discovered in a narrowband infrared survey that targeted the redshifts of damped Lyα or metal lines in the spectra of quasars. The presence of emission lines is inferred from the photometric magnitudes in narrowband and broadband interference filters, corresponding to Hα at redshifts of 0.89 (six…
Discovery of Associated Absorption LInes in an X-Ray Warm Absorber: Hubble Space Telescope Observations of PG 1114+445
Elvis, Martin; Wilkes, Belinda; Mathur, Smitha
The unified picture of X-ray/UV absorbers offers a unique opportunity to probe the nuclear environment of active galactic nuclei. To test the unified absorber scenario and to understand the physical properties of the absorber, we obtained the first UV spectrum of PG 1114+445 using the Hubble Space Telescope (HST) Faint Object Spectrograph. PG 1114…
HST WFPC2/Hα Imagery of the Nebula M1-67: A Clumpy LBV Wind Imprinting Itself on the Nebular Structure?
Moffat, Anthony F. J.; Joncas, Gilles; Grosdidier, Yves +1 more
With the Hubble Space Telescope's Wide Field Planetary Camera 2 we have obtained a deep, Hα image of the relatively young ejection-type nebula M1-67 around the runaway Population I Wolf-Rayet star WR 124 (WN 8). This image shows a wealth of complex detail, some of which have never been seen before in such a nebula. In particular, large arcs of neb…
High Minor Ion Outflow Speeds in the Inner Corona and Observed Ion Charge States in Interplanetary Space
Esser, Ruth; Brickhouse, Nancy S.; Edgar, Richard J.
Flow speeds recently derived from chromospheric/transition region and coronal observations indicate that the solar wind acceleration process takes place at heights in the solar atmosphere much lower than previously imagined. Doppler-dimming observations of the O VI λ1032 and λ1037 spectral lines show that this is not only true for the background e…
Power-Law Decays in the Optical Counterparts of GRB 970228 and GRB 970508
Kouveliotou, C.; van Paradijs, J.; McClintock, J. E. +7 more
We report on RC- and K-band observations of the optical counterpart to GRB 970508 with the Fred Lawrence Whipple Observatory (FLWO) 1.2 m telescope. Eleven RC-band observations were obtained on 1997 May 12, and three on May 14. The counterpart clearly faded between the two nights. On May 12 there was no evidence for variabili…
Detection of Far-Infrared Water Vapor, Hydroxyl, and Carbon Monoxide Emissions from the Supernova Remnant 3C 391
Reach, William T.; Rho, Jeonghee
We report the detection of shock-excited far-infrared emission of H2O, OH, and CO from the supernova remnant 3C 391, using the Infrared Space Observatory Long-Wavelength Spectrometer. This is the first detection of thermal H2O and OH emission from a supernova remnant. For two other remnants, W28 and W44, CO emission was detec…
The Lensing Cluster MS 0440+0204 Seen by HST, ROSAT, and ASCA. I. Cluster Properties
Le Fèvre, O.; Hammer, F.; Falco, E. E. +3 more
We present an analysis of the properties of the lensing cluster MS 0440+0204 at z = 0.1965. MS 0440+0204 has been observed with a variety of telescopes at diverse wavelengths: from the ground with the Canada-France-Hawaii Telescope, the Multiple Mirror Telescope, and the Keck Telescope, and from the Earth orbit with HST, ROSAT, and ASCA. Mass dete…
Photometric Evolution of Galaxies in Cosmological Scenarios
Steinmetz, Matthias; Contardo, Gertrud; Fritze-von Alvensleben, Uta
The photometric evolution of galaxies in a hierarchically clustering universe is investigated. The study is based on high-resolution numerical simulations that include the effects of gasdynamics, shock heating, radiative cooling, and a heuristic star formation scheme. The outcome of the simulations is convolved with photometric models, which enabl…
The ASCA X-Ray Spectrum of η Carinae
Koyama, K.; Davidson, K.; Corcoran, M. F. +9 more
We have obtained high signal-to-noise ratio 0.5-10 keV band X-ray spectra of the peculiar, extremely luminous star η Carinae with the Advanced Satellite for Cosmology and Astrophysics (ASCA) X-ray observatory during Cycle 4 observations in mid-1996. These data comprise the best X-ray spectra to date of the cool source (kT ~ 0.3 keV) surrounding th…