Search Publications
Missions
Journals
Publication Years
HST Observations and Models of the Gravitational Lens System MG 0414+0534
Falco, Emilio E.; Lehar, Joseph; Shapiro, Irwin I.
Quadruple gravitational lens systems offer the possibility of measuring time delays for image pairs, microlensing effects, and extinction in distant galaxies. Observations of these systems may be used to obtain estimates of H0 and to study the various mass components of lens galaxies at high redshifts. With the Hubble Space Telescope, w…
Bursts of Explosive Events in the Solar Network
Wilhelm, K.; Innes, D. E.; Brekke, P. +1 more
Observations of the quiet-Sun network in the UV emission line Siiv 1393 Å over a time period of two hours are presented. Bursts of explosive events, highly Doppler-shifted emission, seem to be sporadically emitted from the brighter regions of the network lanes. Individual events have typical lifetimes of ≈ 1-6 min and come in bursts of up to 30 mi…
A Survey for Large-Image Separation Lensed Quasars
Maoz, Dan; Rix, Hans-Walter; Gould, Andrew +1 more
The statistics of gravitationally lensed quasars with multiple images in the 0.1"-7" range have been measured in various surveys. Little is known, however, about lensed-quasar statistics at larger image separations, which probe masses on the scale of galaxy clusters. We extend the results of the Hubble Space Telescope (HST) Snapshot Survey for Len…
ISOCAM 7 micron deep survey of the Lockman Hole: A mid-infrared search for primeval galaxies
Sanders, D. B.; Kawara, K.; Taniguchi, Y. +11 more
We present results of our 7 mu m deep survey program made with ISOCAM, the infrared camera of ISO (Infrared Space Observatory). We have found 15 sources above a 5 sigma_rms significance in a small selected area (3(') x 3(') ) in the Lockman HI hole. Among the 15 sources, 14 objects have also been observed in the near infrared (NIR: ~ 2 mu m). The …
First results from UVCS/SOHO
Romoli, M.; Raymond, J. C.; Naletto, G. +20 more
We present here the first results obtained by the Ultraviolet Coronagraph Spectrometer (UVCS) operating on board the SOHO satellite. The UVCS started to observe the extended corona at the end of January 1996; it routinely obtains coronal spectra in the 1145 A˚ - 1287 A˚, 984 A˚ - 1080 A˚ ranges, and intensity data in the visible continuum. Through…
The Star-grazing Extrasolar Comets in the HD 100546 System
Sitko, M. L.; Grady, C. A.; Bjorkman, Karen S. +4 more
Redshifted absorption profiles that resemble the high-velocity circumstellar gas features in the spectrum of β Pictoris have been detected in IUE data for the 10 Myr old Herbig Be star, HD 100546, on 1995 March 7. In addition to Mg II, Si II, and other refractory species similar to those seen in β Pic, the HD 100546 spectra are rich in accreting g…
A Hubble Space Telescope Faint Object Spectrograph Survey for Broad Absorption Lines in a Sample of Low-redshift Weak [O III] Quasi-stellar Objects
Turnshek, David A.; Espey, Brian R.; Monier, Eric M. +1 more
The study by Boroson & Meyers led to the suggestion that radio-quiet QSOs with weak [O III] and strong Fe II emission spectra form a class of QSOs that has a high probability of exhibiting broad absorption lines (BALs) in their spectra. Furthermore, they argued that since narrow-line [O III] emission is almost certainly emitted isotropically, …
Mars surface mineralogy from Hubble Space Telescope imaging during 1994-1995: Observations, calibration, and initial results
Bell, James F.; Wolff, Michael J.; Clancy, R. Todd +3 more
Visible to near-infrared observations of Mars were made with the Hubble Space Telescope (HST) during 1994-1995 with the goals of monitoring seasonal variability of the surface and atmosphere and mapping specific spectral units to constrain the planet's surface mineralogy. This paper presents the details of the collection and calibration of the dat…
Evidence for an outflow from the Seyfert galaxy NGC 4051
Steffen, W.; Mundell, C. G.; Meaburn, J. +5 more
New observations using narrow-band imaging, long-slit spectroscopy and MERLIN observations of the nuclear region of the Seyfert galaxy NGC 4051 have been made. An edge-brightened, triangular region of ionized gas extending 420 pc from the centre of the galaxy has been detected. Long-slit spectra of this ionized gas, taken at 1.5 arcsec from the co…
SUMER Observations of the Quiet Solar Atmosphere: The Network Chromosphere and Lower Transition Region
Wilhelm, Klaus; Carlsson, Mats; Judge, Philip
We examine spectral properties of the network chromosphere and lower transition region from the SUMER instrument on the SOHO spacecraft, using time-series data sets discussed in an accompanying Letter by Carlsson, Judge, & Wilhelm. The data were obtained early in the mission with no tracking of solar features and so cannot generally be used to…