Search Publications
Summer Evolution of the North Polar Cap of Mars as Observed by OMEGA/Mars Express
Bibring, J. -P.; Gondet, B.; Langevin, Y. +3 more
The Observatoire pour la Minéralogie, l'Eau, les Glaces, et l'Activité (OMEGA) visible-infrared imaging spectrometer extensively observed regions of Mars with latitudes above 70°N in late 2004 (heliocentric longitude from Ls 93° to Ls 127°). The extent of water ice at the surface and the size of ice grains were monitored as a…
Quasars and the Big Blue Bump
Kaiser, Mary Elizabeth; Green, Richard F.; Kriss, Gerard A. +10 more
We investigate the ultraviolet-to-optical spectral energy distributions of 17 active galactic nuclei (AGNs) using quasi-simultaneous spectrophotometry spanning 900-9000 Å (rest frame). We employ data from the Far Ultraviolet Spectroscopic Explorer, the Hubble Space Telescope, and the 2.1 m telescope at Kitt Peak National Observatory. Taking advant…
Ices in the Edge-on Disk CRBR 2422.8-3423: Spitzer Spectroscopy and Monte Carlo Radiative Transfer Modeling
van Dishoeck, Ewine F.; Dullemond, Cornelis P.; Pontoppidan, Klaus M. +5 more
We present 5.2-37.2 µm spectroscopy of the edge-on circumstellar disk CRBR 2422.8-3423 obtained using the Infrared Spectrograph (IRS) of the Spitzer Space Telescope. The IRS spectrum is combined with ground-based 3-5 µm spectroscopy to obtain a complete inventory of solid-state material present along the line of sight toward the source…
First Results from the CHARA Array. I. An Interferometric and Spectroscopic Study of the Fast Rotator α Leonis (Regulus)
Gies, D. R.; Berger, D. H.; McAlister, H. A. +13 more
We report on K-band interferometric observations of the bright, rapidly rotating star Regulus (type B7 V) made with the CHARA Array on Mount Wilson, California. Through a combination of interferometric and spectroscopic measurements, we have determined for Regulus the equatorial and polar diameters and temperatures, the rotational velocity and per…
Direction of the interstellar H atom inflow in the heliosphere: Role of the interstellar magnetic field
Izmodenov, V.; Alexashov, D.; Myasnikov, A.
Recently Lallement et al. (2005, Science, 307, 1447) reported that the direction of the flow of interstellar neutral hydrogen in the heliosphere is deflected by ~4° from the direction of the pristine local interstellar gas flow. The most probable physical phenomenon responsible for such a deviation is the interstellar magnetic field inclined to th…
Visibility of coronal mass ejections as a function of flare location and intensity
Howard, R. A.; Gopalswamy, N.; Michalek, G. +2 more
We report the visibility (detection efficiency) of coronal mass ejections (CMEs) of the Large Angle Spectrometric Coronagraph (LASCO) on board the Solar and Heliospheric Observatory (SOHO). We collected 1301 X-ray flare events (above C3 level) detected by the GOES satellite and examined their CME associations using data from LASCO coronagraphs. Th…
Compositional maps of Saturn's moon Phoebe from imaging spectroscopy
Sotin, C.; Baines, K. H.; Nicholson, P. D. +23 more
The origin of Phoebe, which is the outermost large satellite of Saturn, is of particular interest because its inclined, retrograde orbit suggests that it was gravitationally captured by Saturn, having accreted outside the region of the solar nebula in which Saturn formed. By contrast, Saturn's regular satellites (with prograde, low-inclination, ci…
The Evolution and Structure of Early-Type Field Galaxies: A Combined Statistical Analysis of Gravitational Lenses
Kochanek, C. S.; Rusin, D.
We introduce a framework for simultaneously investigating the structure and luminosity evolution of early-type gravitational lens galaxies. The method is based on the fundamental plane, which we interpret using the aperture mass-radius relations derived from lensed image geometries. We apply this method to our previous sample of 22 lens galaxies w…
Abundance trends in kinematical groups of the Milky Way's disk
Soubiran, C.; Girard, P.
We have compiled a large catalogue of metallicities and abundance ratios from the literature in order to investigate abundance trends of several alpha and iron peak elements in the thin disk and the thick disk of the Galaxy. The catalogue includes 743 stars with abundances of Fe, O, Mg, Ca, Ti, Si, Na, Ni and Al in the metallicity range -1.30 <…
Mapping the Kinematics of the Narrow-Line Region in the Seyfert Galaxy NGC 4151
Gull, T. R.; Kraemer, S. B.; Crenshaw, D. M. +6 more
Using the Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS), observations of the [O III] emission from the narrow-line region (NLR) of NGC 4151 were obtained and radial velocities determined. Five orbits of HST time were used to obtain spectra at five parallel slit configurations at a position angle of 58°, with spatial reso…