Search Publications
Photoionization of Disk Winds
Chiang, J.; Murray, N.
The disk-wind model suggests that the broad emission lines of a quasar are emitted from the surface of the accretion disk feeding the central black hole. In this paper, we assume that a line-driven wind emerges from the illuminated face of the disk and calculate the line emission produced by this wind. The location and mass-loss rate of the wind a…
Spatially Resolved STIS Spectroscopy of SN 1987A: Evidence for Shock Interaction with Circumstellar Gas
Lundqvist, P.; Gull, T. R.; McCray, R. +15 more
Visual and ultraviolet spatially resolved (~0.1") spectra of SN 1987A obtained on days 3715 and 3743 with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope show that the high-velocity supernova debris is colliding with circumstellar gas. Very broad Lyα emission with velocities extending to ~+/-20,000 km s-1 originat…
Far-Ultraviolet Spectra of Starburst Galaxies: Stellar Population and the Kinematics of the Interstellar Medium
Ferguson, Henry C.; Robert, Carmelle; Heckman, Timothy +3 more
The far-ultraviolet spectra of the four starburst galaxies NGC 6090, Mrk 66, Mrk 1267, and IRAS 0833+6517 were observed with the Hopkins Ultraviolet Telescope during the Astro-2 mission. Additional data were obtained for IRAS 0833+6517 with the Goddard High-Resolution Spectrograph (GHRS) on the Hubble Space Telescope. We analyze the observations i…
Measurements of Solar Magnetic Element Dispersal
Berger, Thomas E.; Shine, Richard A.; Title, Alan M. +1 more
The dispersal of magnetic elements in the solar photospheric flow field is studied by tracking individual ``magnetic bright points'' (MBPs) identified in a G-band 4305 Å filtergram time series obtained at the 50 cm Swedish Vacuum Solar Telescope on La Palma, Spain. The time series spans approximately 70 minutes with a field of view of 29" × 29" ne…
IRAS 23385+6053: A Prototype Massive Class 0 Object
Testi, Leonardo; Molinari, Sergio; Brand, Jan +2 more
IRAS 23385+6053 is a young stellar object with a luminosity of ~1.6×104 Lsolar at a kinematic distance of 4.9 kpc. This candidate precursor of an ultracompact H II region is associated with a millimeter source detected at the James Clerk Maxwell Telescope but is undetected at centimeter wavelengths with the VLA. We observed t…
Dust Emission and Molecular Depletion in L1498
Langer, W. D.; Velusamy, T.; Willacy, K.
We present 100 and 200 µm ISOPHOT observations of the dense core L1498. We have mapped the central core by using ΔI200=I200-I100/Θ, where ΔI200 is a measure of the emission from the cold dust and Θ=I100/I200 in the outer regions. The dust continuum emission provides informatio…
Steps toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XIII. Ultraviolet Observations of the Broad-Line Radio Galaxy 3C 390.3
Shull, J. M.; Malkan, M. A.; Martin, P. G. +44 more
As part of an extensive multiwavelength monitoring campaign, the International Ultraviolet Explorer satellite was used to observe the broad-line radio galaxy 3C 390.3 during the period 1994 December 31-1996 March 5. Spectra were obtained every 6-10 days. The UV continuum varied by a factor of 7 through the campaign, while the broad emission lines …
Emission Features and Source Counts of Galaxies in the Mid-Infrared
Xu, Cong; Ashby, Matthew L. N.; Shupe, David L. +6 more
In this work we incorporate the newest Infrared Space Observatory (ISO) results on the mid-infrared spectral energy distributions (MIR SEDs) of galaxies into models for the number counts and redshift distributions of MIR surveys. A three-component model, with empirically determined MIR SED templates of (1) a cirrus/photodissociation region compone…
Optical Structure and Colors of Faint Compact Narrow Emission-Line Galaxies
Bershady, Matthew A.; Koo, David C.; Simard, Luc +2 more
We present the results of Hubble Space Telescope Wide Field Planetary Camera imaging in V606 and I814 of five compact narrow emission line galaxies (CNELGs) and four slightly more extended faint blue galaxies (FBGs) with 20.3<=B<=22.4 and redshifts z~0.22-0.66. Half-light radii are measured to span from 0.14" to 0.67", …
A Search for Ultraviolet Emission from LINERs
Filippenko, Alexei V.; Ho, Luis C.; Barth, Aaron J. +1 more
We have obtained Hubble Space Telescope Wide Field and Planetary Camera 2 ultraviolet (UV) 2200 Å and optical V-band images of 20 low-luminosity active galactic nuclei, most of which are spectroscopically classified as LINERs, in order to search for a possible photoionizing continuum. Six (30%) of the galaxies are detected in the UV. Two of the de…