Search Publications
An Analysis of the Shapes of Interstellar Extinction Curves. V. The IR-through-UV Curve Morphology
Fitzpatrick, E. L.; Massa, D.
We study the IR-through-UV interstellar extinction curves towards 328 Galactic B and late-O stars. We use a new technique which employs stellar atmosphere models in lieu of unreddened "standard" stars. This technique is capable of virtually eliminating spectral mismatch errors in the curves. It also allows a quantitative assessment of the errors a…
A Triple Main Sequence in the Globular Cluster NGC 2808
Anderson, J.; Milone, A. P.; Bedin, L. R. +6 more
Accurate photometry with HST's ACS shows that the main sequence (MS) of the globular cluster NGC 2808 splits into three separate branches. The three MS branches may be associated with the complexities of the cluster's horizontal branch and of its abundance distribution. We attribute the MS branches to successive rounds of star formation, with diff…
The ACS Virgo Cluster Survey. XIII. SBF Distance Catalog and the Three-dimensional Structure of the Virgo Cluster
Jordán, Andrés; Tonry, John L.; Côté, Patrick +7 more
The ACS Virgo Cluster Survey consists of HST ACS imaging for 100 early-type galaxies in the Virgo Cluster, observed in the F475W (~SDSS g) and F850LP (~SDSS z) filters. We derive distances for 84 of these galaxies using the method of surface brightness fluctuations (SBFs), present the SBF distance catalog, and use this database to examine the thre…
Scrutinizing Exotic Cosmological Models Using ESSENCE Supernova Data Combined with Other Cosmological Probes
Becker, A. C.; Sollerman, J.; Spyromilio, J. +25 more
The first cosmological results from the ESSENCE supernova survey (Wood-Vasey and coworkers) are extended to a wider range of cosmological models including dynamical dark energy and nonstandard cosmological models. We fold in a greater number of external data sets such as the recent Higher-z release of high-redshift supernovae (Riess and coworkers)…
UV Luminosity Functions at z~4, 5, and 6 from the Hubble Ultra Deep Field and Other Deep Hubble Space Telescope ACS Fields: Evolution and Star Formation History
Franx, Marijn; Bouwens, R. J.; Illingworth, G. D. +1 more
We use the ACS BViz data from the HUDF and all other deep HST ACS fields (including the GOODS fields) to find large samples of star-forming galaxies at z~4 and ~5 and to extend our previous z~6 sample. These samples contain 4671, 1416, and 627 B-, V-, and i-dropouts, respectively, and reach to extremely low luminosities [(0.01-0.04)L*
The All-Wavelength Extended Groth Strip International Survey (AEGIS) Data Sets
Smail, I.; Le Floc'h, E.; Barmby, P. +53 more
In this the first of a series of Letters, we present a panchromatic data set in the Extended Groth Strip region of the sky. Our survey, the All-Wavelength Extended Groth Strip International Survey (AEGIS), aims to study the physical properties and evolutionary processes of galaxies at z~1. It includes the following deep, wide-field imaging data se…
Star Formation in NGC 5194 (M51a). II. The Spatially Resolved Star Formation Law
Gordon, Karl D.; Bot, Caroline; Calzetti, Daniela +20 more
We have studied the relationship between the star formation rate (SFR), surface density, and gas surface density in the spiral galaxy M51a (NGC 5194), using multiwavelength data obtained as part of the Spitzer Infrared Nearby Galaxies Survey (SINGS). We introduce a new SFR index based on a linear combination of Hα emission-line and 24 µm con…
Radio Loudness of Active Galactic Nuclei: Observational Facts and Theoretical Implications
Stawarz, Łukasz; Sikora, Marek; Lasota, Jean-Pierre
We investigate how the total radio luminosity of AGN-powered radio sources depends on their accretion luminosity and the central black hole mass. Our studies cover about 7 orders of magnitude in accretion luminosity (expressed in Eddington units, i.e., as Eddington ratios) and the full range of AGN black hole masses. We find that AGNs form two dis…
The Sloan Lens ACS Survey. IV. The Mass Density Profile of Early-Type Galaxies out to 100 Effective Radii
Treu, Tommaso; Gavazzi, Raphaël; Koopmans, Léon V. E. +5 more
We present a weak-lensing analysis of 22 early-type (strong) lens galaxies, based on deep HST images obtained as part of the Sloan Lens ACS Survey. Using advanced techniques to control systematic uncertainties, we show that weak-lensing signal is detected out to ~300 h-1 kpc (at the mean lens redshift z=0.2). We analyze blank control fi…
The Masses of Nuclear Black Holes in Luminous Elliptical Galaxies and Implications for the Space Density of the Most Massive Black Holes
Filippenko, Alexei V.; Ho, Luis C.; Gebhardt, Karl +11 more
Black hole (BH) masses predicted from the M•-σ relationship conflict with predictions from the M•-L relationship for high-luminosity galaxies, such as brightest cluster galaxies (BCGs). The M•-L relationship predicts that some BCGs may harbor BHs with M• approaching 1010 Msolar, whi…