Search Publications
Constraints on the Size Evolution of Brightest Cluster Galaxies
Gonzalez, Anthony H.; Zaritsky, Dennis; Dalcanton, Julianne J. +2 more
We measure the luminosity profiles of 16 brightest cluster galaxies (BCGs) at 0.4<z<0.8 using high-resolution F160W NICMOS and F814W WFPC2 Hubble Space Telescope imaging. The heterogeneous sample is drawn from a variety of surveys: seven from clusters in the Einstein Medium Sensitivity Survey, five from the Las Campanas Distant Cluster Surve…
FUSE Observations of the Cygnus Loop: O VI Emission from a Nonradiative Shock
Blair, William P.; Sankrit, Ravi
We present Far Ultraviolet Spectroscopic Explorer (FUSE) observations of a Balmer filament in the northeast region of the Cygnus Loop supernova remnant. The data consist of one spectrum obtained through the 30''×30'' (LWRS) aperture and three spectra at adjacent positions obtained through the 4''×20'' (M…
Hubble Space Telescope Imaging of Bipolar Nuclear Shells in the Disturbed Virgo Cluster Galaxy NGC 4438
Kenney, Jeffrey D. P.; Yale, Elizabeth E.
We present broadband and narrowband Hubble Space Telescope (HST) images of the central region of the heavily disturbed Virgo cluster galaxy NGC 4438 (Arp 120), whose nucleus has been described as a type 1 LINER or dwarf Seyfert galaxy. Narrowband Hα and [N II] HST images reveal striking bipolar shell features, 1 kpc in projected length from end to…
Production, Outflow Velocity, and Radial Distribution of H2O and OH in the Coma of Comet C/1995 O1 (Hale-Bopp) from Wide-Field Imaging of OH
Harris, Walter M.; Scherb, Frank; Mierkiewicz, Edwin +2 more
Observations of OH are a useful proxy of the water production rate (QH2O) and outflow velocity (VH2O) in comets. From wide-field images taken on 1997 March 28 and April 8 that capture the entire scale length of the OH coma of comet C/1995 O1 (Hale-Bopp), we obtain QOH from the model-independen…
Kinematics of Galaxies in the Hubble Deep Field-South: Discovery of a Very Massive Spiral Galaxy at z = 0.6
Aussel, H.; Genzel, R.; Franceschini, A. +3 more
We report the first results from a study of the internal kinematics, based on spatially resolved Hα velocity profiles, of three galaxies at redshift z~0.6 and one at redshift z~0.8, detected by ISOCAM in the Hubble Deep Field-South. The kinematics are derived from high-resolution near-IR Very Large Telescope spectroscopy. One of the galaxies is a …
3-20 MeV Electrons in the Inner Three-dimensional Heliosphere at Solar Maximum: Ulysses COSPIN/KET Observations
Fichtner, H.; Schlickeiser, R.; Kunow, H. +10 more
The Ulysses trajectory provides a unique opportunity to study the propagation of MeV electrons in a wide range of heliographic latitudes and during varying conditions in the inner heliosphere. From the Ulysses launch up to the beginning of 1998, the 3-10 MeV electron count rate of the COSPIN/KET instrument has been consistently described by modula…
Witnessing the Hierarchical Assembly of the Brightest Cluster Galaxy in a Cluster at z=1.26
Kodama, Tadayuki; Tanaka, Ichi; Yamada, Toru +5 more
We have obtained a new high-resolution K'-band image of the central region of the rich X-ray cluster RX J0848.9+4452 at z=1.26. We found that the brightest cluster galaxy (BCG) in the cluster is clearly separated into two distinct objects. Whereas the optical to near-infrared colors of the objects are consistent with the predictions of …
Evidence for a Fast Decline in the Progenitor Population of Gamma-Ray Bursts and the Nature of Their Origin
Hurley, K.; Atteia, J. -L.; Stern, B. E.
We show that the source population of long gamma-ray bursts (GRBs) has declined by at least a factor of 12 (at the 90% confidence level) since the early stages of the universe (z~2-3). This result has been obtained using the combined BATSE and Ulysses GRB brightness distribution and the detection of four GRBs with known redshifts brighter than 10<…
Statistical Correlations between Solar Microwave Bursts and Coronal Mass Ejections
Dougherty, Brian L.; Zirin, Harold; Hsu, Kathryn
We compare listings of coronal mass ejections (CMEs) observed by LASCO on SOHO and solar microwave bursts (SMBs) recorded by the Radio Solar Telescope Network (RSTN) operated by the United States Air Force. These data sets are the product of stable and continuous observations of the whole Sun and provide suitable bases for robust statistical studi…
The Abundance of Atomic Sulfur in the Atmosphere of Io
Feldman, Paul D.; McGrath, Melissa A.; Feaga, Lori M.
Observations with the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope have been used to constrain the atomic sulfur column density in Io's atmosphere. The S I λ1479 dipole allowed and forbidden transition multiplets have been resolved for the first time at Io, enabling the study of both optically thick and thin transitions f…