Search Publications
The COS-Halos Survey: Keck LRIS and Magellan MagE Optical Spectroscopy
Tripp, Todd M.; Prochaska, J. Xavier; Tumlinson, Jason +4 more
We present high signal-to-noise optical spectra for 67 low-redshift (0.1 < z < 0.4) galaxies that lie within close projected distances (5 kpc < ρ < 150 kpc) of 38 background UV-bright QSOs. The Keck LRIS and Magellan MagE data presented here are part of a survey that aims to construct a statistically sampled map of the physical state a…
The age of the Milky Way inner halo
Kalirai, Jason S.
The Milky Way galaxy has several components, such as the bulge, disk and halo. Unravelling the assembly history of these stellar populations is often restricted because of difficulties in measuring accurate ages for low-mass, hydrogen-burning stars. Unlike these progenitors, white dwarf stars, the `cinders' of stellar evolution, are remarkably sim…
SGRs and AXPs as Rotation-Powered Massive White Dwarfs
Malheiro, Manuel; Rueda, Jorge A.; Ruffini, Remo
SGR 0418+5729 is a ``Rosetta Stone'' for deciphering the energy source of Soft Gamma Ray Repeaters (SGRs) and Anomalous X-ray Pulsars (AXPs). We present a model based on canonical physics and astrophysics for SGRs and AXPs powered by massive highly magnetized rotating white dwarfs (WDs), in total analogy with pulsars powered by rotating neutron st…
A 200-Second Quasi-Periodicity After the Tidal Disruption of a Star by a Dormant Black Hole
Miller, J. M.; Reis, R. C.; Maitra, D. +4 more
Supermassive black holes (SMBHs; mass is greater than or approximately 105 times that of the Sun) are known to exist at the center of most galaxies with sufficient stellar mass. In the local universe, it is possible to infer their properties from the surrounding stars or gas. However, at high redshifts we require active, continuous accr…
The 60 Month All-sky Burst Alert Telescope Survey of Active Galactic Nucleus and the Anisotropy of nearby AGNs
Greiner, J.; Alexander, D. M.; Ajello, M. +3 more
Surveys above 10 keV represent one of the best resources to provide an unbiased census of the population of active galactic nuclei (AGNs). We present the results of 60 months of observation of the hard X-ray sky with Swift/Burst Alert Telescope (BAT). In this time frame, BAT-detected (in the 15-55 keV band) 720 sources in an all-sky survey of whic…
LoCuSS: The Sunyaev-Zel'dovich Effect and Weak-lensing Mass Scaling Relation
Smith, Graham P.; Gralla, Megan; Mroczkowski, Tony +22 more
We present the first weak-lensing-based scaling relation between galaxy cluster mass, M WL, and integrated Compton parameter Y sph. Observations of 18 galaxy clusters at z ~= 0.2 were obtained with the Subaru 8.2 m telescope and the Sunyaev-Zel'dovich Array. The M WL-Y sph scaling relations, measured at …
A Hubble Space Telescope Survey of H2 Emission in the Circumstellar Environments of Young Stars
Herczeg, Gregory J.; Brown, Alexander; France, Kevin +8 more
The formation timescale and final architecture of exoplanetary systems are closely related to the properties of the molecular disks from which they form. Observations of the spatial distribution and lifetime of the molecular gas at planet-forming radii (a < 10 AU) are important for understanding the formation and evolution of exoplanetary syste…
An active region filament studied simultaneously in the chromosphere and photosphere. I. Magnetic structure
Martínez Pillet, V.; Centeno, R.; Kuckein, C.
Aims: A thorough multiwavelength, multiheight study of the vector magnetic field in a compact active region filament (NOAA 10781) on 2005 July 3 and 5 is presented. We suggest an evolutionary scenario for this filament.
Methods: Two different inversion codes were used to analyze the full Stokes vectors acquired with the Tenerife Infrared…
The Solar Neighborhood. XXVIII. The Multiplicity Fraction of Nearby Stars from 5 to 70 AU and the Brown Dwarf Desert around M Dwarfs
Krist, John E.; Golimowski, David A.; Henry, Todd J. +2 more
We report on our analysis of Hubble Space Telescope/NICMOS snapshot high-resolution images of 255 stars in 201 systems within ~10 pc of the Sun. Photometry was obtained through filters F110W, F180M, F207M, and F222M using NICMOS Camera 2. These filters were selected to permit clear identification of cool brown dwarfs through methane contrast imagi…
APEX-CHAMP+ high-J CO observations of low-mass young stellar objects. III. NGC 1333 IRAS 4A/4B envelope, outflow, and ultraviolet heating
van Dishoeck, Ewine F.; Güsten, Rolf; van der Marel, Nienke +5 more
Context. The