Search Publications
Dust Absorption and the Ultraviolet Luminosity Density at z ~ 3 as Calibrated by Local Starburst Galaxies
Heckman, Timothy M.; Meurer, Gerhardt R.; Calzetti, Daniela
We refine a technique to measure the absorption-corrected ultraviolet (UV) luminosity of starburst galaxies using rest-frame UV quantities alone and apply it to Lyman-limit U dropouts at z~3 found in the Hubble Deep Field (HDF). The method is based on an observed correlation between the ratio of far-infrared (FIR) to UV fluxes with spectral slope …
Measuring and modelling the redshift evolution of clustering: the Hubble Deep Field North
Matarrese, S.; Fontana, A.; Cristiani, S. +4 more
The evolution of galaxy clustering from z=0 to z~=4.5 is analysed using the angular correlation function and the photometric redshift distribution of galaxies brighter than IAB<=28.5 in the Hubble Deep Field North. The reliability of the photometric redshift estimates is discussed on the basis of the available spectroscopic redshifts…
The Luminosity Function of Young Star Clusters in ``the Antennae'' Galaxies (NGC 4038-4039)
Leitherer, Claus; Whitmore, Bradley C.; Fall, S. Michael +3 more
The Wide Field Planetary Camera 2 of the Hubble Space Telescope has been used to obtain high-resolution images of NGC 4038/4039 that go roughly 3 mag deeper in V than previous observations made during cycle 2. These new images allow us to measure the luminosity functions (LFs) of clusters and stars over a range of 8 mag (-14<M_V<-6). To firs…
A Spectroscopic Catalog of 10 Distant Rich Clusters of Galaxies
Smail, Ian; Ellis, Richard S.; Dressler, Alan +4 more
We present spectroscopic observations of galaxies in the fields of 10 distant clusters for which we have previously presented deep imaging with WFPC2 on board the Hubble Space Telescope. The clusters span the redshift range z=0.37-0.56 and are the subject of a detailed ground- and space-based study to investigate the evolution of galaxies as a fun…
Heavy-Element Abundances in Blue Compact Galaxies
Thuan, Trinh X.; Izotov, Yuri I.
We present high-quality ground-based spectroscopic observations of 54 supergiant H II regions in 50 low-metallicity blue compact galaxies with oxygen abundances 12+logO/H between 7.1 and 8.3. We use the data to determine abundances for the elements N, O, Ne, S, Ar, and Fe. We also analyze Hubble Space Telescope (HST) Faint Object Spectrograph arch…
The afterglow, redshift and extreme energetics of the γ-ray burst of 23 January 1999
Kelson, D. D.; Malkan, M. A.; Harrison, F. A. +26 more
Long-lived emission, known as afterglow, has now been detected from about a dozen γ-ray bursts. Distance determinations place the bursts at cosmological distances, with redshifts, z, ranging from ~1 to 3. The energy required to produce these bright γ-ray flashes is enormous: up to ~10 53erg, or 10 per cent of the rest-mass energy of a n…
Hubble Space Telescope/NICMOS Observations of Massive Stellar Clusters near the Galactic Center
Rich, R. Michael; Serabyn, Eugene; Figer, Donald F. +3 more
We report Hubble Space Telescope (HST) Near-Infrared Camera and Multiobject Spectrometer (NICMOS) observations of the Arches and Quintuplet clusters, two extraordinary young clusters near the Galactic center. For the first time, we have identified main-sequence stars in the Galactic center with initial masses well below 10 Msolar. We pr…
The Spectral Energy Distributions of Low-Luminosity Active Galactic Nuclei
Ho, Luis C.
As a step toward elucidating the physical conditions in nearby active galaxies, this paper presents spectral energy distributions (SEDs) of a sample of seven low-luminosity active galactic nuclei (AGNs). SEDs for four objects are presented for the first time (NGC 4261, NGC 4579, NGC 6251, and M84); the data for the remaining three (M81, M87, and N…
A New Catalog of Photometric Redshifts in the Hubble Deep Field
Lanzetta, Kenneth M.; Yahil, Amos; Fernández-Soto, Alberto
Using the newly available infrared images of the Hubble Deep Field in the J, H, and K bands and an optimal photometric method, we have refined a technique to estimate the redshifts of 1067 galaxies. A detailed comparison of our results with the spectroscopic redshifts in those cases where the latter are available shows that this technique gives ve…
Hubble Space Telescope Observations of Superluminal Motion in the M87 Jet
Sparks, W. B.; Macchetto, F.; Biretta, J. A.
We present observations of the M87 jet made with the Faint Object Camera on board the Hubble Space Telescope at five epochs between 1994 and 1998. These observations reveal 10 superluminal features within the first 6" of the jet, with eight of these having apparent speeds in the range 4c-6c. Two additional features within the first arcsecond of th…