Search Publications
The c2d Spitzer Spectroscopic Survey of Ices around Low-Mass Young Stellar Objects. I. H2O and the 5-8 µm Bands
Augereau, J. -C.; Stapelfeldt, K. R.; van Dishoeck, E. F. +23 more
To study the physical and chemical evolution of ices in solar-mass systems, a spectral survey is conducted of a sample of 41 low-luminosity YSOs (L ~ 0.1-10 L⊙) using 3-38 µm Spitzer and ground-based spectra. The sample is complemented with previously published Spitzer spectra of background stars and with ISO spectra of well-studi…
The ACS Virgo Cluster Survey. XV. The Formation Efficiencies of Globular Clusters in Early-Type Galaxies: The Effects of Mass and Environment
Jordán, Andrés; Tonry, John L.; Côté, Patrick +8 more
The fraction of stellar mass contained in globular clusters (GCs), also measured by number as the specific frequency, is a fundamental quantity that reflects both a galaxy's early star formation and its entire merging history. We present specific frequencies, luminosities, and mass fractions for the globular cluster systems of 100 early-type galax…
UV Excess Measures of Accretion onto Young Very Low Mass Stars and Brown Dwarfs
Herczeg, Gregory J.; Hillenbrand, Lynne A.
Low-resolution spectra from 3000 to 9000 Å of young low-mass stars and brown dwarfs were obtained with LRIS on Keck I. The excess UV and optical emission arising in the Balmer and Paschen continua yields mass accretion rates ranging from 2 × 10-12 to 10-8 M⊙ yr-1. These results are compared with HST STIS…
The Initial-Final Mass Relation: Direct Constraints at the Low-Mass End
Kelson, Daniel D.; Rich, R. Michael; Hansen, Brad M. S. +3 more
The initial-final mass relation represents a mapping between the mass of a white dwarf remnant and the mass that the hydrogen-burning main-sequence star that created it once had. The empirical relation thus far has been constrained using a sample of ~40 stars in young open clusters, ranging in initial mass from ~2.75 to 7 M⊙, and shows …
The Structure of the Local Interstellar Medium. IV. Dynamics, Morphology, Physical Properties, and Implications of Cloud-Cloud Interactions
Redfield, Seth; Linsky, Jeffrey L.
We present an empirical dynamical model of the LISM based on 270 radial velocity measurements for 157 sight lines toward nearby stars. Physical parameter measurements (i.e., temperature, turbulent velocity, depletions) are available for 90 components, or one-third of the sample, enabling initial characterizations of the physical properties of LISM…
FIREWORKS U38-to-24 µm Photometry of the GOODS Chandra Deep Field-South: Multiwavelength Catalog and Total Infrared Properties of Distant Ks-selected Galaxies
van Dokkum, Pieter G.; Franx, Marijn; Labbé, Ivo +4 more
We present a Ks-selected catalog, dubbed FIREWORKS, for the Chandra Deep Field-South (CDF-S) containing photometry in the U38, B435, B, V, V606, R, i775, I, z850, J, H, Ks, [3.6 µm], [4.5 µm], [5.8 µm], [8.0 µm], and MIPS [24 µm] bands. The i…
z ~ 7-10 Galaxies in the HUDF and GOODS Fields: UV Luminosity Functions
Franx, Marijn; Illingworth, Garth D.; Bouwens, Rychard J. +1 more
We use all available deep optical ACS and near-IR data over both the HUDF and the two GOODS fields to search for star-forming galaxies at zgtrsim 7 and constrain the UV LF within the first 700 Myr. Our data set includes ~23 arcmin2 of deep NICMOS J + H data and ~248 arcmin2 of ground-based (ISAAC+MOIRCS) data, coincident with…
Swift BAT Survey of AGNs
Gehrels, N.; Mushotzky, R. F.; Barthelmy, S. +5 more
We present the results of the analysis of the first 9 months of data of the Swift BAT survey of AGNs in the 14-195 keV band. Using archival X-ray data or follow-up Swift XRT observations, we have identified 129 (103 AGNs) of 130 objects detected at | b| > 15° and with significance >4.8 σ. One source remains unidentified. These same X-ray dat…
The ACS Survey of Galactic Globular Clusters. III. The Double Subgiant Branch of NGC 1851
Anderson, J.; Milone, A. P.; Sarajedini, A. +13 more
Photometry with the Hubble Space Telescope Advanced Camera for Surveys (HST ACS) reveals that the subgiant branch (SGB) of the globular cluster NGC 1851 splits into two well-defined branches. If the split is due only to an age effect, the two SGBs would imply two star formation episodes separated by ~1 Gyr. We discuss other anomalies in NGC 1851 t…
Revealing the Properties of Dark Matter in the Merging Cluster MACS J0025.4-1222
Treu, Tommaso; Bradač, Maruša; Allen, Steven W. +5 more
We constrain the physical nature of dark matter using the newly identified massive merging galaxy cluster MACS J0025.4-1222. As was previously shown by the example of the Bullet Cluster (1E 0657-56), such systems are ideal laboratories for detecting isolated dark matter and distinguishing between cold dark matter (CDM) and other scenarios (e.g., s…