Search Publications
Mass Segregation in the Globular Cluster NGC 6397
Cool, Adrienne M.; King, Ivan R.; Sosin, Craig
Our deep HST images of the center of the globular cluster NGC 6397 are almost devoid of faint stars, implying that these stars must be much less concentrated to the cluster center than the brighter stars. This difference is an expected consequence of energy exchanges through stellar encounters, which give higher velocities to lower mass stars and …
The Abundances of Pt, Au, and HG in the Chemically Peculiar HgMn-Type Stars kappa CANCRI and chi LUPI
Wahlgren, Glenn M.; Brage, Tomas; Leckrone, David S. +2 more
Echelle mode spectra obtained with the Goddard High Resolution Spectrograph (GHRS) onboard the Hubble Space Telescope (HST) have been used to determine the abundances of the heavy elements Pt, Au, and Hg in the chemically peculiar HgMn-type stars kappa Cancri and chi Lupi. The abundances were determined by fitting observed line profiles with synth…
The Unusual Quasar PG 1407+265
Elvis, Martin; Wilkes, Belinda J.; McDowell, Jonathan C. +4 more
PG 1407+265, discovered in the Palomar-Green Survey (Schmidt & Green 1983), was identified as a z ∼ 1 radio-quiet quasar on the basis of a single weak line. Further observations over a wide wavelength range confirm the identification but reveal the object to have unusual emission-line properties. Broad Hα is the only strong emission line with …
Radio and Emission-Line Jets in the Type 2 Seyfert Galaxy Markarian 1066 (UGC 2456)
Mulchaey, John; Bower, Gary; Morse, Jon A. +3 more
Hubble Space Telescope FOS Spectroscopy of the Ultrashort-Period Dwarf Nova WZ Sagittae: The Underlying Degenerate
Szkody, Paula; Sion, Edward M.; Hubeny, Ivan +4 more
Two consecutive Hubble Space Telescope (HST) Faint Object Spectrograph (FOS) spectra of the exposed white dwarf in the ultrashort-period, high-amplitude, dwarf nova WZ Sge, reveal a rich absorption line spectrum of neutron carbon and ionized metals, the Stark-broadened Lyman-alpha absorption wing, the H2 quasi-molecular Lyman-alpha 'satellite' abs…
HST Imaging Polarimetry of NGC 1068
Boksenberg, A.; Capetti, A.; Sparks, W. B. +2 more
We present the results of high-quality pre-refurbishment HST imaging polarimetry of NGC 1068 obtained with the Faint Object Camera in the ultraviolet ( 2700-3700 A), and the Wide Field Planetary Camera in the visual (λ ∼ 5000-6000 Å), with resolutions of 0".06 and 0".08, respectively.
The polarization of the UV continuum is very high, peaking…Hubble Space Telescope Far-Ultraviolet Imaging of M31, M32, and NGC 205
Bressan, A.; di Serego Alighieri, S.; Buson, L. M. +3 more
Hubble Space Telescope Faint Object Camera (FOC) f/48 images of M31, M32, and NGC 205 (field of view 23" x 23" with 0.45" pixel size) are analyzed as observed through the combined UV filters F150W and F130LP. The absolute calibration of the data and the internal disagreement between observed and expected count rates in the UV region lead us to sug…
The Active Phase of the Hot Component of Z Andromedae
Gonzalez-Riestra, R.; Seaquist, E. R.; Cassatella, A. +2 more
Z And is considered the prototype of the symbolic class. Quiescence data show that its hot component lies close to the central stars of planetary nebulae in the H-R diagram. This system underwent an outburst at the beginning of 1984. The activity phase lasted for approximately 900 days with two maxima in 1984 April and 1985 December. In this work …
An HST Archival Study of Galactic Interstellar Zinc and Chromium
Roth, Katherine C.; Blades, J. Chris
We present a survey of interstellar Zn II and Cr II absorption extracted from the Hubble Space Telescope Goddard High Resolution Spectrograph (HST GHRS) data archive. We find clear evidence for an enhanced depletion of Zn from the gas phase with increasing fractional abundance of molecular hydrogen f(H2). Our lower limit to the Galactic interstell…
Scattering Properties of the Dust in the Reflection Nebula IC 435
Gordon, Karl D.; Calzetti, Daniela; Bianchi, Luciana +2 more
New lUE observations of the reflection nebula IC 435 are presented, and the scattering properties of the nebular dust grains are derived. Previous studies of this nebula suggested the presence of enhanced scattering in the 2175 Å interstellar extinction bump, which the new data do not confirm. The UV observations plus optical data from the literat…