Search Publications
Spectroscopic Confirmation of an Extreme Starburst at Redshift 4.547
Aussel, H.; Sanders, D. B.; Ilbert, O. +22 more
We report the spectroscopic confirmation of a submillimeter galaxy (SMG) at z = 4.547 with an estimated LIR = (0.5-2.0) × 1013 L⊙. The spectra, mid-IR, and X-ray properties indicate the bolometric luminosity is dominated by star formation at a rate of >1000 M⊙ yr-1. Multiple, spatially sepa…
Lyman Break Galaxies, Lyα Emitters, and a Radio Galaxy in a Protocluster at z = 4.1
Ford, H. C.; Demarco, R.; Zheng, W. +17 more
We present deep HST ACS observations in g475r625i775z850 toward the z = 4.1 radio galaxy TN J1338-1942 and its overdensity of >30 spectroscopically confirmed Lyα emitters (LAEs). We select 66 g475 band dropouts to z850,5 σ = 27, 6 of which are also LAEs. Although our color-color …
Exoplanet HD 209458b (Osiris): Evaporation Strengthened
Lecavelier des Etangs, A.; Ferlet, R.; Vidal-Madjar, A. +4 more
Following reanalysis of Hubble Space Telescope observations of primary transits of the extrasolar planet HD 209458b at Lyα, Ben-Jaffel claims that no sign of evaporation is observed. Here we show that, in fact, this new analysis is consistent with the one of Vidal-Madjar and coworkers, and supports the detection of evaporation. The apparent disagr…
A Global Kinetic Model for Cometary Comae: The Evolution of the Coma of the Rosetta Target Comet Churyumov-Gerasimenko throughout the Mission
Tenishev, Valeriy; Combi, Michael; Davidsson, Björn
The Rosetta spacecraft is en route to comet 67P/Churyumov-Gerasimenko for a rendezvous, landing, and extensive orbital phase beginning in 2014. Model studies of the coma will be required not only for planning of the mission and interpretation of spacecraft data, but also for an expectedly large amount of complementary remote observational data tha…
A Multisite Campaign to Measure Solar-like Oscillations in Procyon. I. Observations, Data Reduction, and Slow Variations
Reffert, Sabine; Butler, R. Paul; Bertaux, Jean-Loup +45 more
We have carried out a multisite campaign to measure oscillations in the F5 star Procyon A. We obtained high-precision velocity observations over more than three weeks with 11 telescopes, with almost continuous coverage for the central 10 days. This represents the most extensive campaign so far organized on any solar-type oscillator. We describe in…
X-Ray and Optical Microlensing in the Lensed Quasar PG 1115+080
Morgan, Nicholas D.; Dai, Xinyu; Morgan, Christopher W. +2 more
We analyzed the microlensing of the X-ray and optical emission of the lensed quasar PG 1115+080. We find that the effective radius of the X-ray emission is 1.3+ 1.1-0.5 dex smaller than that of the optical emission. Viewed as a thin disk observed at inclination angle i, the optical accretion disk has a scale length, defined b…
The X-Ray Spectral Evolution in X-Ray Binaries and Its Application to Constrain the Black Hole Mass of Ultraluminous X-Ray Sources
Wu, Qingwen; Gu, Minfeng
We investigate the relationship between the hard X-ray photon index Γ and the Eddington ratio [ξ = LX(0.5-25 keV)/LEdd] in six X-ray binaries (XRBs) with well-constrained black hole masses and distances. We find that different XRBs follow different anticorrelations between Γ and ξ when ξ is less than a critical value, while Γ…
Double Coronal Hard and Soft X-Ray Source Observed by RHESSI: Evidence for Magnetic Reconnection and Particle Acceleration in Solar Flares
Liu, Wei; Dennis, Brian R.; Jiang, Yan Wei +1 more
We present data analysis and interpretation of an M1.4 class flare observed with the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) on 2002 April 30. This event, with its footpoints occulted by the solar limb, exhibits a rarely observed, but theoretically expected, double-source structure in the corona. The two coronal sources, obse…
The Recent Star Formation Histories of M81 Group Dwarf Irregular Galaxies
Cannon, John M.; Dolphin, Andrew E.; Skillman, Evan D. +4 more
We present observations and analysis of nine dwarf irregular galaxies (dIs) in the M81 Group taken with the Advanced Camera for Surveys aboard the Hubble Space Telescope. The nine galaxies (the Garland, M81 Dwarf A, DDO 53, Ho IX, Ho I, DDO 165, NGC 2366, Ho II, and IC 2574) span 6 mag in luminosity, a factor of 1000 in current star formation rate…
Extrasolar Giant Planets and X-Ray Activity
Drake, Jeremy J.; Kashyap, Vinay L.; Saar, Steven H.
We have carried out a survey of X-ray emission from stars with giant planets, combining both archival and targeted surveys. Over 230 stars have been currently identified as possessing planets, and roughly one-third of these have been detected in X-rays. We carry out detailed statistical analysis on a volume-limited sample of main-sequence star sys…