Search Publications
SDSS J160531.84+174826.1: A Dwarf Disk Galaxy with an Intermediate-Mass Black Hole
Yuan, Weimin; Zhou, Hongyan; Wang, Huiyuan +7 more
We report the discovery of a dwarf Seyfert 1 active galactic nucleus (AGN) with a candidate intermediate-mass black hole, hosted by the dwarf galaxy SDSS J160531.84+174826.1 at z=0.032. A broad component of the Hα line with FWHM=781 km s-1 is detected in its optical spectrum, and a bright, pointlike nucleus is evident from a Hubble Spac…
VLT and ACS Observations of RDCS J1252.9-2927: Dynamical Structure and Galaxy Populations in a Massive Cluster at z = 1.237
Ford, H. C.; Demarco, R.; Infante, L. +26 more
We present results from an extensive spectroscopic survey, carried out with VLT FORS, and from an extensive multiwavelength imaging data set from the HST Advanced Camera for Surveys and ground-based facilities, of the cluster of galaxies RDCS J1252.9-2927. We have spectroscopically confirmed 38 cluster members in the redshift range 1.22<z<1.…
Spitzer Identifications and Classifications of Submillimeter Galaxies in Giant, High-Redshift, Lyα-Emission-Line Nebulae
Ivison, R. J.; Smail, Ian; Alexander, D. M. +4 more
Using Spitzer Space Telescope IRAC (3.6-8 µm) and MIPS (24 µm) imaging, as well as Hubble Space Telescope optical observations, we identify the IRAC counterparts of the luminous power sources residing within the two largest and brightest Lyα-emitting nebulae (LABs) in the SA 22 protocluster at z=3.09 (LAB 1 and LAB 2). These sources ar…
Intense Star Formation and Feedback at High Redshift: Spatially Resolved Properties of the z = 2.6 Submillimeter Galaxy SMM J14011+0252
Lutz, D.; Genzel, R.; Baker, A. J. +9 more
We present a detailed analysis of the spatially resolved properties of the lensed submillimeter galaxy (SMG) SMM J14011+0252 at z=2.56, combining deep near-infrared integral-field data obtained with SPIFFI on the VLT with other multiwavelength data sets. As previously discussed by other authors, the broad characteristics of SMM J14011+0252 in part…
On the Variation of the Peak Asymmetry of Low-l Solar p Modes
Howe, R.; Jiménez-Reyes, S. J.; García, R. A. +4 more
The resonant peaks of solar p modes show small amounts of asymmetry in frequency. Here, we use five independent sets of contemporaneous data, collected over a ~=8 yr period, to investigate whether peak asymmetry in low angular degree p modes changes over the solar activity cycle. Three of the data sets are from instruments on board the ESA/NASA SO…
Searching for Earth Analogs Around the Nearest Stars: The Disk Age-Metallicity Relation and the Age Distribution in the Solar Neighborhood
Valenti, Jeff A.; Reid, I. Neill; Turnbull, Margaret C. +2 more
The chemical composition of Earth's atmosphere has undergone substantial evolution over the course of its history. It is possible, even likely, that terrestrial planets in other planetary systems have undergone similar changes; consequently, the age distribution of nearby stars is an important consideration in designing surveys for Earth analogs. …
The Aptly Named Phoenix Dwarf Galaxy
Dolphin, Andrew E.; Skillman, Evan D.; Weisz, Daniel R. +1 more
The Local Group galaxy Phoenix has the properties of a dwarf spheroidal galaxy, but an adjacent H I cloud has been recently found to be at the same radial velocity as the stars. The proximity suggests that this cloud is associated with the most recent (<=100 Myr) star formation in Phoenix. We have obtained relatively high sensitivity and high r…
Joint Analysis of Cluster Observations. I. Mass Profile of Abell 478 from Combined X-Ray, Sunyaev-Zel'dovich, and Weak-Lensing Data
Hoekstra, Henk; Babul, Arif; Mahdavi, Andisheh +3 more
We provide a new framework for the joint analysis of cluster observations (JACO) using simultaneous fits to X-ray, Sunyaev-Zel'dovich (SZ), and weak-lensing data. Our method fits the mass models simultaneously to all data, provides explicit separation of the gaseous, dark, and stellar components, and-for the first time-allows joint constraints on …
Magnetic Helicity Injection in Active Regions
Chae, Jongchul; Jeong, Hyewon
Magnetic helicity is now regarded as an important physical quantity in understanding solar magnetic activities. We have studied the injection of magnetic helicity through the photosphere of four active regions during the long periods of their lifetimes. The rate of helicity injection was determined as a function of time in each active region by ap…
Preferential Perpendicular Heating of Coronal Hole Minor Ions by the Fermi Mechanism
Isenberg, Philip A.; Vasquez, Bernard J.
We present a kinetic mechanism for the preferential perpendicular heating of minor ions in coronal holes, which may be responsible for the consistent observation in fast solar wind that the heavy ions are hotter and flow faster than the proton population. The basis of this mechanism is the familiar resonant cyclotron interaction between ions and p…