Search Publications
The ACS Virgo Cluster Survey. I. Introduction to the Survey
Jordán, Andrés; Tonry, John L.; Côté, Patrick +7 more
The Virgo Cluster is the dominant mass concentration in the Local Supercluster and the largest collection of elliptical and lenticular galaxies in the nearby universe. In this paper, we present an introduction to the ACS Virgo Cluster Survey: a program to image, in the F475W and F850LP bandpasses (~Sloan g and z), 100 early-type galaxies in the Vi…
The Anatomy of Star Formation in NGC 300
Helou, G.; Roussel, H.; Fazio, G. G. +19 more
The Spitzer Space Telescope was used to study the mid- to far-infrared properties of NGC 300 and to compare dust emission to Hα to elucidate the heating of the interstellar medium (ISM) and the star formation cycle at scales smaller than 100 pc. The new data allow us to discern clear differences in the spatial distribution of 8 µm dust emiss…
An Extended Scheme for Fitting X-Ray Data with Accretion Disk Spectra in the Strong Gravity Regime
Yaqoob, T.; Dovčiak, M.; Karas, V.
Accreting black holes are believed to emit X-rays, which then mediate information about strong gravity in the vicinity of the emission region. We report on a set of new routines for the XSPEC package for analyzing X-ray spectra of black-hole accretion disks. The new computational tool significantly extends the capabilities of the currently availab…
Polycyclic Aromatic Hydrocarbon Contribution to the Infrared Output Energy of the Universe at z ~= 2
Le Floc'h, E.; Dole, H.; Lagache, G. +10 more
We present an updated phenomenological galaxy evolution model to fit the Spitzer 24, 70, and 160 µm number counts, as well as all the previous mid- and far-infrared observations. Only a minor change of the comoving luminosity density distribution in the previous model (Lagache, Dole, & Puget), combined with a slight modification of the s…
A Galactic O Star Catalog
Walborn, Nolan R.; Maíz-Apellániz, Jesús; Galué, Héctor Á. +1 more
We have produced a catalog of 378 Galactic O stars with accurate spectral classifications that is complete for V<8 but includes many fainter stars. The catalog provides cross-identifications with other sources; coordinates (obtained in most cases from Tycho-2 data); astrometric distances for 24 of the nearest stars; optical (Tycho-2, Johnson, a…
Faint Galaxies in Deep Advanced Camera for Surveys Observations
Infante, L.; Zheng, W.; Feldman, P. D. +33 more
We present the analysis of the faint galaxy population in the Advanced Camera for Surveys (ACS) Early Release Observation fields VV 29 (UGC 10214) and NGC 4676. These observations cover a total area of 26.3 arcmin2 and have depths close to that of the Hubble Deep Fields in the deepest part of the VV 29 image, with 10 σ detection limits …
The Local Lyα Forest. IV. Space Telescope Imaging Spectrograph G140M Spectra and Results on the Distribution and Baryon Content of H I Absorbers
Shull, J. Michael; Stocke, John T.; Penton, Steven V.
We present Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) G140M spectra of 15 extragalactic targets, which we combine with GHRS/G160M data to examine the statistical properties of the low-z Lyα forest. With STIS, we detect 109 Lyα absorbers at significance level (SL) of >=4 σ over 0.002<z<0.069, with a total reds…
Hubble Space Telescope Observations of the White Dwarf Cooling Sequence of M4
Currie, Thayne; Rich, R. Michael; Gibson, Brad K. +7 more
We investigate in detail the white dwarf cooling sequence of the globular cluster Messier 4. In particular, we study the influence of various systematic uncertainties, both observational and theoretical, on the determination of the cluster age from the white dwarf cooling sequence. These include uncertainties in the distance to the cluster and the…
Physical Properties and Baryonic Content of Low-Redshift Intergalactic Lyα and O VI Absorption Line Systems: The PG 1116+215 Sight Line
Richter, Philipp; Tripp, Todd M.; Sembach, Kenneth R. +1 more
We present Hubble Space Telescope and Far Ultraviolet Spectroscopic Explorer observations of the intergalactic absorption toward QSO PG 1116+215 in the 900-3000 Å spectral region. We detect 25 Lyα absorbers along the sight line at rest-frame equivalent widths Wr>30 mÅ, yielding (dN/dz)Lyα=166+/-20 over an unblocked redshif…
GRAPES, Grism Spectroscopy of the Hubble Ultra Deep Field: Description and Data Reduction
Cimatti, A.; Daddi, E.; Panagia, N. +19 more
We present deep unbiased spectroscopy of the Hubble Ultra Deep Field (UDF) carried out using the slitless grism spectroscopy mode of the Advanced Camera for Surveys on the Hubble Space Telescope (HST). The Grism ACS Program for Extragalactic Science (GRAPES) achieves continuum detection as faint as zAB=27.2 using 40 orbits (9.2×104…