Search Publications
Hierarchical Structure Formation and Modes of Star Formation in Hickson Compact Group 31
Hornschemeier, A. E.; Mendes de Oliveira, C.; Young, J. +12 more
The handful of low-mass, late-type galaxies that comprise Hickson Compact Group 31 (HCG 31) is in the midst of complex, ongoing gravitational interactions, evocative of the process of hierarchical structure formation at higher redshifts. With sensitive, multicolor Hubble Space Telescope imaging, we characterize the large population of < 10 Myr …
On the Constancy of the Solar Radius. III.
Kuhn, J. R.; Bush, R. I.; Emilio, M.
The Michelson Doppler Imager on board the Solar and Heliospheric Observatory satellite has operated for over a sunspot cycle. This instrument is now relatively well understood and provides a nearly continuous record of the solar radius in combination with previously developed algorithms. Because these data are obtained from above Earth's atmospher…
In situ observations of the effect of a solar wind compression on Saturn's magnetotail
Coates, A. J.; Dougherty, M. K.; Jackman, C. M. +4 more
In this paper we explore the dynamic response of Saturn's magnetotail to an episode of solar wind compression that took place while Cassini was sampling Saturn's nightside equatorial magnetosphere in 2006. Following an initial increase in solar wind dynamic pressure the magnetosphere was compressed, but over several subsequent days the flaring of …
Discovery of a Faint Companion to Alcor Using MMT/AO 5 µm Imaging
Meyer, Michael R.; Kenworthy, Matthew A.; Mamajek, Eric E. +1 more
We report the detection of a faint stellar companion to the famous nearby A5V star Alcor (80 UMa). The companion has M-band (λ = 4.8 µm) magnitude 8.8 and projected separation 1.''11 (28 AU) from Alcor. The companion is most likely a low-mass (~0.3 M ⊙) active star which is responsible for Alcor's X-ray emission detected by ROSAT …
The quasar MBH-Mhost relation through cosmic time - I. Data set and black hole masses
Falomo, R.; Treves, A.; Decarli, R. +3 more
We study the relation as a function of cosmic time in a sample of 96 quasars from z = 3 to the present epoch. In this paper, we describe the sample, the data sources and the new spectroscopic observations. We then illustrate how we derive from single-epoch spectra, pointing out the uncertainties in the procedure. In a companion paper, we address t…
SGR-like flaring activity of the anomalous X-ray pulsar 1E 1547.0-5408
Walter, R.; Savchenko, V.; Produit, N. +2 more
Aims: We studied an exceptional period of activity of the anomalous X-ray pulsar1E 1547.0-5408 in January 2009, during which about 200 hard X-ray / soft γ-ray bursts were detected by different instruments on board of ESA's γ-ray observatory INTEGRAL.
Methods: The major activity episode (22 January 2009), which was detected by NASA's γ-ra…
The Mass of the Candidate Exoplanet Companion to HD 136118 from Hubble Space Telescope Astrometry and High-Precision Radial Velocities
Harrison, Thomas E.; Bean, Jacob L.; Benedict, G. Fritz +3 more
We use Hubble Space Telescope fine guidance sensor astrometry and high-cadence radial velocities for HD 136118 from the Hobby-Eberly Telescope with archival data from Lick to determine the complete set of orbital parameters for HD 136118 b. We find an orbital inclination for the candidate exoplanet of ib = 163fdg1 ± 3fdg0. This establis…
The far-infrared/submillimeter properties of galaxies located behind the Bullet cluster
Smail, I.; Kneib, J. -P.; Smith, G. P. +45 more
The Herschel Lensing Survey (HLS) takes advantage of gravitational lensing by massive galaxy clusters to sample a population of high-redshift galaxies which are too faint to be detected above the confusion limit of current far-infrared/submillimeter telescopes. Measurements from 100-500 µm bracket the peaks of the far-infrared spectral energ…
The X-ray source content of the XMM-Newton Galactic plane survey
Motch, C.; Carrera, F.; Guillout, P. +10 more
We report the results of an optical campaign carried out by the XMM-Newton Survey Science Centre with the specific goal of identifying the brightest X-ray sources in the XMM-Newton Galactic plane survey. In addition to photometric and spectroscopic observations obtained at the ESO-VLT and ESO-3.6 m, we used cross-correlations with the 2XMMi, USNO-…
Cosmic Origins Spectrograph and FUSE Observations of T ~ 105 K Gas in a Nearby Galaxy Filament
Sembach, Kenneth R.; Savage, Blair D.; Shull, J. Michael +4 more
We present a clear detection of a broad Lyα absorber (BLA) with a matching O VI line in the nearby universe. The BLA is detected at z(Lyα}) = 0.01028 in the high signal-to-noise ratio spectrum of Mrk 290 obtained using the Cosmic Origins Spectrograph. The Lyα absorption has two components, with b(H I) = 55 ± 1 km s-1 and b(H I) = 33 ± 1…