Search Publications
The template type Ia supernova 1996X
Turatto, M.; Cappellaro, E.; Benetti, S. +4 more
UBVRIJ photometry and optical spectra of the type Ia SN 1996X obtained at the European Southern Observatory (ESO) during a 1-yr-long observational campaign are presented, and supplemented by late-time Hubble Space Telescope (HST) photometry. Spectroscopically, SN 1996X appears to be a `normal' SN Ia. The apparent magnitude at maximum was B=13.24+/…
A Hubble Space Telescope Lensing Survey of X-Ray Luminous Galaxy Clusters. I. A383
Smith, Graham P.; Smail, Ian; Kneib, Jean-Paul +2 more
We present an analysis of the mass distribution in the core of A383 (z=0.188), one of 12 X-ray luminous galaxy clusters at z~0.2 selected for a comprehensive and unbiased study of the mass distribution in massive galaxy clusters. Deep optical imaging performed by the Hubble Space Telescope (HST) reveals a wide variety of gravitationally lensed fea…
Stellar populations and surface brightness fluctuations: new observations and models
Vazdekis, Alexandre; Ajhar, Edward A.; Blakeslee, John P.
We investigate the use of surface brightness fluctuations (SBF) measurements in optical and near-IR bandpasses for both stellar population and distance studies. New V-band SBF data are reported for five galaxies in the Fornax cluster and combined with literature data to define a V-band SBF distance indicator, calibrated against Cepheid distances t…
On the Origin of Intrinsic Narrow Absorption Lines in z<~1 QSOS
Charlton, Jane C.; Brandt, W. N.; Churchill, Christopher W. +3 more
We present an exhaustive statistical analysis of the associated (Δvabs<5000 km s-1), high-ionization (C IV, N V, O VI) narrow absorption line (NAL) systems in a sample of 59 QSOs defined from the Hubble Space Telescope (HST) QSO Absorption Line Key Project. The goals of the research were twofold: (1) to determine the frequ…
Luminosity Evolution of Field Early-Type Galaxies to Z=0.55
van Dokkum, Pieter G.; Franx, Marijn; Kelson, Daniel D. +1 more
We study the fundamental plane (FP) of field early-type galaxies at intermediate redshift, using Hubble Space Telescope Wide Field Planetary Camera 2 observations and deep Keck spectroscopy. Structural parameters and internal velocity dispersions are measured for 18 galaxies at 0.15<z<0.55. Rest-frame M/LB ratios are determined fr…
Deep Hubble Space Telescope Imaging of IC 1613. I. Variable Stars and Distance
Dolphin, Andrew E.; Skillman, Evan D.; Saha, A. +6 more
We present WFPC2 VI photometry of a field in the halo of IC 1613, finding 13 RR Lyrae stars and 11 Cepheids. Our photometry of the red giant branch tip and red clump is used to derive distances to IC 1613, which are consistent with each other and with distances based on the variable stars. We compare these values with similarly measured distances …
Search for NH3 ice in cold dust envelopes around YSOs
Dartois, E.; d'Hendecourt, L.
We present a study of the 3.1 micron absorption band, attributed to the OH stretching mode of the water molecule in the form of solid ice, observed in many protostellar lines of sight by the SWS instrument on board ISO. Using ice optical constants and Mie theory, we obtain reasonable fits to the peculiar band shapes observed in twelve sources. The…
A Low Global Star Formation Rate in the Rich Galaxy Cluster AC 114 at z=0.32
Smail, Ian; Glazebrook, Karl; Balogh, Michael L. +3 more
We present the results of a wide-field survey for Hα-emitting galaxies in the cluster AC 114 at z=0.32. Spectra centered on Hα at the cluster redshift have been obtained for 586 galaxies to Itot~22 out to a radius of ~2 h-150 Mpc. At most, only ~10% of these were found to be Hα-emitting cluster members. These objec…
Substantial reservoirs of molecular hydrogen in the debris disks around young stars
Thi, W. F.; Natta, A.; van Dishoeck, E. F. +7 more
Circumstellar accretion disks transfer matter from molecular clouds to young stars and to the sites of planet formation. The disks observed around pre-main-sequence stars have properties consistent with those expected for the pre-solar nebula from which our own Solar System formed 4.5Gyr ago. But the `debris' disks that encircle more than 15% of n…
Models for Multiband Infrared Surveys
Xu, Cong; Shupe, David L.; Lonsdale, Carol J. +2 more
Empirical ``backward'' galaxy evolution models for IR bright galaxies are constrained using multiband IR surveys. A new Monte Carlo algorithm is developed for this task. It exploits a large library of realistic spectral energy distributions (SEDs) of 837 local IR galaxies (IRAS 25 µm selected) from the UV (1000 Å) to the radio (20 cm), inclu…