Search Publications
Spectra and Hubble Space Telescope Light Curves of Six Type Ia Supernovae at 0.511 < z < 1.12 and the Union2 Compilation
Panagia, N.; Wang, L.; Lidman, C. +43 more
We report on work to increase the number of well-measured Type Ia supernovae (SNe Ia) at high redshifts. Light curves, including high signal-to-noise Hubble Space Telescope data, and spectra of six SNe Ia that were discovered during 2001, are presented. Additionally, for the two SNe with z > 1, we present ground-based J-band photometry from Gem…
The Structure and Kinematics of the Circumgalactic Medium from Far-ultraviolet Spectra of z ~= 2-3 Galaxies
Pettini, Max; Erb, Dawn K.; Shapley, Alice E. +5 more
We present new results on the kinematics and spatial distribution of metal-enriched gas within ~125 kpc of star-forming ("Lyman break") galaxies at redshifts 2 <~ z <~ 3. In particular, we focus on constraints provided by the rest-frame far-ultraviolet (far-UV) spectra of faint galaxies, and demonstrate how galaxy spectra can be used to obta…
Very High Gas Fractions and Extended Gas Reservoirs in z = 1.5 Disk Galaxies
Daddi, E.; Elbaz, D.; Stern, D. +10 more
We present evidence for very high gas fractions and extended molecular gas reservoirs in normal, near-infrared-selected (BzK) galaxies at z ~ 1.5. Our results are based on multi-configuration CO[2-1] observations obtained at the IRAM Plateau de Bure Interferometer. All six star-forming galaxies observed were detected at high significance. High spa…
Galaxy Stellar Mass Assembly Between 0.2 < z < 2 from the S-COSMOS Survey
Kneib, J. -P.; Aussel, H.; Le Floc'h, E. +22 more
We follow the galaxy stellar mass assembly by morphological and spectral type in the COSMOS 2 deg2 field. We derive the stellar mass functions and stellar mass densities from z = 2 to z = 0.2 using 196,000 galaxies selected at F 3.6 µm > 1 µJy with accurate photometric redshifts (σ_{(z_phot-z_spec)/(1+z_spec)}=…
The Sloan Lens ACS Survey. X. Stellar, Dynamical, and Total Mass Correlations of Massive Early-type Galaxies
Treu, T.; Auger, M. W.; Gavazzi, R. +5 more
We use stellar masses, surface photometry, strong-lensing masses, and stellar velocity dispersions (σ e/2) to investigate empirical correlations for the definitive sample of 73 early-type galaxies (ETGs) that are strong gravitational lenses from the SLACS survey. The traditional correlations (fundamental plane (FP) and its projections) …
The ACS Survey of Galactic Globular Clusters. IX. Horizontal Branch Morphology and the Second Parameter Phenomenon
Anderson, Jay; Dotter, Aaron; Sarajedini, Ata +11 more
The horizontal branch (HB) morphology of globular clusters (GCs) is most strongly influenced by metallicity. The second parameter phenomenon, first described in the 1960s, acknowledges that metallicity alone is not enough to describe the HB morphology of all GCs. In particular, astronomers noticed that the outer Galactic halo contains GCs with red…
Dissecting the Gravitational lens B1608+656. II. Precision Measurements of the Hubble Constant, Spatial Curvature, and the Dark Energy Equation of State
Treu, T.; Blandford, R. D.; Auger, M. W. +5 more
Strong gravitational lens systems with measured time delays between the multiple images provide a method for measuring the "time-delay distance" to the lens, and thus the Hubble constant. We present a Bayesian analysis of the strong gravitational lens system B1608+656, incorporating (1) new, deep Hubble Space Telescope (HST) observations, (2) a ne…
The Initial Mass Function of Early-Type Galaxies
Treu, Tommaso; Gavazzi, Raphaël; Marshall, Philip J. +3 more
We determine an absolute calibration of the initial mass function (IMF) of early-type galaxies, by studying a sample of 56 gravitational lenses identified by the Sloan Lenses ACS Survey. Under the assumption of standard Navarro, Frenk, and White dark matter halos, a combination of lensing, dynamical, and stellar population synthesis models is used…
Discovery of z ~ 8 Galaxies in the Hubble Ultra Deep Field from Ultra-Deep WFC3/IR Observations
Trenti, M.; Oesch, P. A.; Carollo, C. M. +8 more
We utilize the newly acquired, ultra-deep WFC3/IR observations over the Hubble Ultra Deep Field (HUDF) to search for star-forming galaxies at z ~ 8-8.5, only 600 million years from recombination, using a Y 105-dropout selection. The new 4.7 arcmin2 WFC3/IR observations reach to ~28.8 AB mag (5σ) in the Y 105 J
The ACS Nearby Galaxy Survey Treasury. IX. Constraining Asymptotic Giant Branch Evolution with Old Metal-poor Galaxies
Williams, Benjamin F.; Gilbert, Karoline M.; Boyer, Martha L. +10 more
In an attempt to constrain evolutionary models of the asymptotic giant branch (AGB) phase at the limit of low masses and low metallicities, we have examined the luminosity functions and number ratios between AGB and red giant branch (RGB) stars from a sample of resolved galaxies from the ACS Nearby Galaxy Survey Treasury. This database provides Hu…