Search Publications
A Magellan MIKE and Spitzer MIPS Study of 1.5-1.0 M sun Stars in Scorpius-Centaurus
Weinberger, Alycia J.; Chen, Christine H.; Mamajek, Eric E. +3 more
We obtained Spitzer Space Telescope Multiband Imaging Photometer for Spitzer (MIPS) 24 µm and 70 µm observations of 182 nearby, Hipparcos F- and G-type common proper motion single and binary systems in the nearest OB association, Scorpius-Centaurus. We also obtained Magellan/MIKE R ~ 50,000 visual spectra at 3500-10500 Å for 181 candid…
An Accounting of the Dust-obscured Star Formation and Accretion Histories Over the Last ~11 Billion Years
Frayer, D. T.; Chary, R. -R.; Dickinson, M. +3 more
We report on an accounting of the star-formation- and accretion-driven energetics of 24 µm-detected sources in the Great Observatories Origins Deep Survey-North field. For sources having infrared (IR; 8-1000 µm) luminosities gsim3 × 1012 L sun when derived by fitting local spectral energy distributions (SEDs) to 2…
The ACS LCID Project. V. The Star Formation History of the Dwarf Galaxy LGS-3: Clues to Cosmic Reionization and Feedback
Ferguson, Henry; Dolphin, Andrew; Tolstoy, Eline +11 more
We present an analysis of the star formation history (SFH) of the transition-type (dIrr/dSph) Local Group galaxy LGS-3 (Pisces) based on deep photometry obtained with the Advanced Camera for Surveys onboard the Hubble Space Telescope. Our observations reach the oldest main-sequence turnoffs at high signal to noise, allowing a time resolution at th…
The HST/ACS Coma Cluster Survey. IV. Intergalactic Globular Clusters and the Massive Globular Cluster System at the Core of the Coma Galaxy Cluster
Ferguson, Henry C.; Miller, Bryan W.; Hudson, Michael J. +21 more
Intracluster stellar populations are a natural result of tidal interactions in galaxy clusters. Measuring these populations is difficult, but important for understanding the assembly of the most massive galaxies. The Coma cluster of galaxies is one of the nearest truly massive galaxy clusters and is host to a correspondingly large system of globul…
The Assembly History of Disk Galaxies. I. The Tully-Fisher Relation to z ~= 1.3 from Deep Exposures with DEIMOS
Treu, Tommaso; Ellis, Richard S.; Miller, Sarah H. +2 more
We present new measures of the evolving scaling relations between stellar mass, luminosity and rotational velocity for a morphologically inclusive sample of 129 disk-like galaxies with z AB < 22.5 in the redshift range 0.2 <z < 1.3, based on spectra from DEep Imaging Multi-Object Spectrograph on the Keck II telescope, multi-col…
A Precise Cluster Mass Profile Averaged from the Highest-quality Lensing Data
Broadhurst, Tom; Zitrin, Adi; Coe, Dan +3 more
We outline our methods for obtaining high-precision mass profiles, combining independent weak-lensing distortion, magnification, and strong-lensing measurements. For massive clusters, the strong- and weak-lensing regimes contribute equal logarithmic coverage of the radial profile. The utility of high-quality data is limited by the cosmic noise fro…
The First Detection of Blue Straggler Stars in the Milky Way Bulge
Brown, Thomas M.; Anderson, Jay; Livio, Mario +8 more
We report the first detections of Blue Straggler Stars (BSS) in the bulge of the Milky Way. Proper motions from extensive space-based observations along a single sight line allow us to separate a sufficiently clean and well-characterized bulge sample such that we are able to detect a small population of bulge objects in the region of the color-mag…
The Strength and Radial Profile of the Coronal Magnetic Field from the Standoff Distance of a Coronal Mass Ejection-driven Shock
Gopalswamy, Nat; Yashiro, Seiji
We determine the coronal magnetic field strength in the heliocentric distance range 6-23 solar radii (Rs) by measuring the shock standoff distance and the radius of curvature of the flux rope during the 2008 March 25 coronal mass ejection imaged by white-light coronagraphs. Assuming the adiabatic index, we determine the Alfvén Mach number, and hen…
First Results from the 3D-HST Survey: The Striking Diversity of Massive Galaxies at z > 1
Schmidt, Kasper B.; van Dokkum, Pieter G.; Franx, Marijn +26 more
We present first results from the 3D-HST program, a near-IR spectroscopic survey performed with the Wide Field Camera 3 (WFC3) on the HST. We have used 3D-HST spectra to measure redshifts and Hα equivalent widths (EWHα) for a complete, stellar mass-limited sample of 34 galaxies at 1 < z < 1.5 with M star > 1011<…
Corona, Jet, and Relativistic Line Models for Suzaku/RXTE/Chandra-HETG Observations of the Cygnus X-1 Hard State
Pottschmidt, Katja; Wilms, Jörn; Tramper, Frank +7 more
Using Suzaku and the Rossi X-ray Timing Explorer (RXTE), we have conducted a series of four simultaneous observations of the galactic black hole candidate Cyg X-1 in what were historically faint and spectrally hard "low states." Additionally, all of these observations occurred near superior conjunction with our line of sight to the X-ray source pa…