Search Publications
Rocky Extrasolar Planetary Compositions Derived from Externally Polluted White Dwarfs
Koester, D.; Zuckerman, B.; Klein, B. +1 more
We report Keck High Resolution Echelle Spectrometer data and model atmosphere analysis of two helium-dominated white dwarfs, PG1225-079 and HS2253+8023, whose heavy pollutions most likely derive from the accretion of terrestrial-type planet(esimal)s. For each system, the minimum accreted mass is ~1022 g, that of a large asteroid. In PG1…
Solar Wind Modeling with Turbulence Transport and Heating
Matthaeus, William H.; Goldstein, Melvyn L.; Usmanov, Arcadi V. +1 more
We have developed an axisymmetric steady-state solar wind model that describes properties of the large-scale solar wind, interplanetary magnetic field, and turbulence throughout the heliosphere from 0.3 AU to 100 AU. The model is based on numerical solutions of large-scale Reynolds-averaged magnetohydrodynamic equations coupled with a set of small…
Morphology and Size Differences Between Local and High-redshift Luminous Infrared Galaxies
Juneau, Stéphanie; Rieke, George H.; Eisenstein, Daniel J. +1 more
We show that the star-forming regions in high-redshift luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs) and submillimeter galaxies (SMGs) have similar physical scales to those in local normal star-forming galaxies. To first order, their higher infrared (IR) luminosities result from higher luminosity surface density. We also find a g…
The first release of data from the Herschel ATLAS: the SPIRE images
Rodighiero, G.; Valtchanov, I.; Ivison, R. J. +26 more
We have reduced the data taken with the Spectral and Photometric Imaging Receiver (SPIRE) photometer on board the Herschel Space Observatory in the Science Demonstration Phase (SDP) of the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS). We describe the data reduction, which poses specific challenges, both because of the large number …
COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses. IX. Time delays, lens dynamics and baryonic fraction in HE 0435-1223
Magain, P.; Koleva, M.; Faure, C. +13 more
We present accurate time delays for the quadruply imaged quasar HE 0435-1223. The delays were measured from 575 independent photometric points obtained in the R-band between January 2004 and March 2010. With seven years of data, we clearly show that quasar image A is affected by strong microlensing variations and that the time delays are best expr…
Energy deposition and primary chemical products in Titan’s upper atmosphere
Lewis, G. R.; Coates, A. J.; Galand, M. +4 more
Cassini results indicate that solar photons dominate energy deposition in Titan's upper atmosphere. These dissociate and ionize nitrogen and methane and drive the subsequent complex organic chemistry. The improved constraints on the atmospheric composition from Cassini measurements demand greater precision in the photochemical modeling. Therefore,…
Submillimetre galaxies reside in dark matter haloes with masses greater than 3×1011 solar masses
Altieri, B.; Aussel, H.; Elbaz, D. +71 more
The extragalactic background light at far-infrared wavelengths comes from optically faint, dusty, star-forming galaxies in the Universe with star formation rates of a few hundred solar masses per year. These faint, submillimetre galaxies are challenging to study individually because of the relatively poor spatial resolution of far-infrared telesco…
X-ray Emission from Optically Selected Radio-intermediate and Radio-loud Quasars
Brandt, W. N.; Schneider, D. P.; Miller, B. P. +3 more
We present the results of an investigation into the X-ray properties of radio-intermediate and radio-loud quasars (RIQs and RLQs, respectively). We combine large, modern optical (e.g., SDSS) and radio (e.g., FIRST) surveys with archival X-ray data from Chandra, XMM-Newton, and ROSAT to generate an optically selected sample that includes 188 RIQs a…
UV-to-FIR Analysis of Spitzer/IRAC Sources in the Extended Groth Strip. I. Multi-wavelength Photometry and Spectral Energy Distributions
Barro, Guillermo; Yamada, T.; Kajisawa, M. +6 more
We present an IRAC 3.6+4.5 µm selected catalog in the Extended Groth Strip (EGS) containing photometry from the ultraviolet to the far-infrared and stellar parameters derived from the analysis of the multi-wavelength data. In this paper, we describe the method used to build coherent spectral energy distributions (SEDs) for all the sources. I…
Causes of low thermospheric density during the 2007-2009 solar minimum
Woods, Thomas N.; Didkovsky, Leonid V.; Solomon, Stanley C. +2 more
Satellite drag data indicate that the thermosphere was lower in density, and therefore cooler, during the protracted solar minimum period of 2007-2009 than at any other time in the past 47 years. Measurements indicate that solar EUV irradiance was also lower than during the previous solar minimum. However, secular change due to increasing levels o…