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Hubble Space Telescope Imaging of the Optical Transient Associated with GRB 970508
Piro, L.; Pian, E.; Palazzi, E. +15 more
We report on Hubble Space Telescope observations of the optical transient (OT) discovered in the error box of the gamma-ray burst GRB 970508. The object was imaged on 1997 June 2 with the Space Telescope Imaging Spectrograph and Near-Infrared Camera and Multiobject Spectrometer. The observations reveal a pointlike source with R = 23.1+/-0.2 and H …
Structure, Excitation, and Kinematics of the Luminous Herbig-Haro Objects 80/81
Raga, A. C.; Reipurth, Bo; Heathcote, Steve
We present a detailed study of the Herbig-Haro objects HH 80/81, twin working surfaces in the highly collimated outflow driven by a luminous young star. High angular resolution emission line images obtained with the Hubble Space Telescope are used together with ground-based low- and high-dispersion spectroscopy, and proper motion measurements to p…
Is There a Deficit of S0 Galaxies at Intermediate Redshift?
Andreon, S.
Two contradictory results on the evolution of SO galaxies now exist in the recent literature: either S0's are old (zformation > 2) and are evolving passively or most of them form at z < 0.5, as implied by the deficit of S0's in intermediate-redshift (z ~ 0.5) clusters. The resolution of this controversy may be that the apparent de…
HIPPARCOS results on massive X-ray binaries
Chevalier, Claude; Ilovaisky, Sergio A.
We present results on parallaxes, magnitudes and proper motions for 17 optically identified massive X-ray binaries (MXRB) which were observed during the Hipparcos astrometry mission. This sample includes the sources detected in the medium-energy range (2-10 keV) having optical counterparts brighter than V=12. We compare the Hipparcos results with …
The gas/solid methane abundance ratio toward deeply embedded protostars
van Dishoeck, E. F.; Whittet, D. C. B.; Schutte, W. A. +3 more
We present the detection of ro-vibrational absorption lines of the deformation mode of gaseous CH_4 toward the massive protostars W 33A, and NGC 7538 : IRS9, using the SWS spectrometer on board of the Infrared Space Observatory. The observed lines indicate that the CH_4 gas is warm (T ~ 90 K), and has a low abundance ( ~ 4 10(-7) ). The CH_4 ice i…
Full Adaptive Optics Images of Asteroids Ceres and Vesta; Rotational Poles and Triaxial Ellipsoid Dimensions
Drummond, Jack D.; Fugate, Robert Q.; Christou, Julian C. +1 more
Adaptive optics (AO) images of asteroids Ceres and Vesta were obtained on September 18-20, 1993, with the 1.5-m telescope at the Starfire Optical Range of the USAF Phillips Laboratory located near Albuquerque, NM. The light source for higher-order wavefront correction was a Rayleigh laser beacon focused at a range of 10.5 km generated by a copper …
An Extendable Galaxy Number Count Model
Gardner, Jonathan P.
I review galaxy number count models and present ncmod, an extendable and general purpose model for comparing and interpreting the results of field galaxy survey data. I develop techniques and software for converting the results of a survey done in one filter into another filter for direct comparison with other surveys. Comparison of the data from …
Compact Lyalpha-emitting Candidates at Z ~= 2.4 in Deep Medium-Band Hubble Space Telescope WFPC2 Images
Keel, William C.; Windhorst, Rogier A.; Pascarelle, Sebastian M.
Medium-band imaging with Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC2) in the F410M filter has previously revealed a population of compact Lyalpha emission objects around the radio galaxy 53W002 at z ~= 2.4. We report detections of similar objects at z ~= 2.4 in random, high-latitude HST parallel observations of three addition…
The Hubble Space Telescope Extragalactic Distance Scale Key Project. X. The Cepheid Distance to NGC 7331
Illingworth, Garth D.; Madore, Barry F.; Freedman, Wendy L. +17 more
The distance to NGC 7331 has been derived from Cepheid variables observed with the Hubble Space Telescope (HST) WFPC2, as part of the Extragalactic Distance Scale Key Project. Multiepoch exposures in F555W (~V) and F814W (~I), with photometry derived independently from DoPHOT and DAOPHOT/ALLFRAME programs, were used to detect a total of 13 reliabl…
Keck Spectroscopy of Candidate 97Proto-Globular Clusters in NGC 1275
Forbes, Duncan A.; Brodie, Jean P.; Huchra, John P. +3 more
Keck spectroscopy of five proto-globular cluster candidates in NGC 1275 has been combined with Hubble Space Telescope Wide Field Planetary Camera 2 photometry to explore the nature and origin of these objects and discriminate between merger and cooling-flow scenarios for globular cluster formation. The objects we have studied are not H ii regions,…