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Outbursts Large and Small from EXO 2030+375
Finger, Mark H.; Wilson, Colleen A.; Camero-Arranz, Ascensión
During the summer of 2006, the accreting X-ray pulsar EXO 2030+375 underwent its first giant outburst since its discovery in 1985. Our observations include the first ever of the rise of a giant outburst of EXO 2030+375. EXO 2030+375 was monitored daily with the Rossi X-Ray Timing Explorer (RXTE) from 2006 June to 2007 May. During the giant outburs…
Geomorphic evidence for former lobate debris aprons at low latitudes on Mars: Indicators of the Martian paleoclimate
Neukum, G.; Hauber, E.; van Gasselt, S. +1 more
Circumferential depressions enclosing mesas and plateaus in the northern Kasei Valles and in the Tartarus Colles regions of Mars are interpreted as indicators of the former extent of lobate debris aprons, thought to be mixtures of ice and clastic particles. These former lobate debris aprons existed about 1 Ga ago and were embayed by lavas or other…
Mid-Infrared Spectra of Optically-Selected Type 2 Quasars
Strauss, Michael A.; Zakamska, Nadia L.; Krolik, Julian H. +1 more
Type 2 quasars are luminous active galactic nuclei (AGNs) whose central engines are seen through large amounts of gas and dust. We present Spitzer spectra of 12 type 2 quasars selected on the basis of their optical emission line properties. Within this sample, we find a surprising diversity of spectra, from those that are featureless to those show…
Performance of the Charge-Injection Capability of Suzaku XIS
Dotani, Tadayasu; Katsuda, Satoru; Yamaguchi, Hiroya +17 more
A charge-injection technique is applied to the X-ray CCD camera, XIS (X-ray Imaging Spectrometer) aboard Suzaku. The charge transfer inefficiency (CTI) in each CCD column (vertical transfer channel) is measured by the injection of charge packets into a transfer channel and subsequent readout. This paper reports on the performances of the charge-in…
Effects of Scattering on Radio Emission from the Quiet Sun at Low Frequencies
MacDowall, R. J.; Thejappa, G.
The observations of the quiet Sun at meter and decameter wavelengths show that its brightness temperatures can be ~1 order of magnitude lower than the expected values of 106 K and the apparent diameters can be very large. We examine whether this unusual behavior is due to refraction in the smoothly varying coronal plasma and scattering …
Heat balance in Titan's atmosphere
Tomasko, M. G.; Bézard, B.; Doose, L. +3 more
The recent measurements of the vertical distribution and optical properties of haze aerosols as well as of the absorption coefficients for methane at long paths and cold temperatures by the Huygens entry probe of Titan permit the computation of the solar heating rate on Titan with greater certainty than heretofore. We use the haze model derived fr…
Unveiling dark haloes in lensing galaxies
Saha, Prasenjit; Ferreras, Ignacio; Burles, Scott
We present a spatially resolved comparison of the stellar mass and total mass surface distributions of nine early-type galaxies. The galaxies are a subset of the Sloan Lens ACS Survey. The total mass distributions are obtained by exploring pixelated mass models that reproduce the lensed images. The stellar mass distributions are derived from popul…
Photometric properties of the Local Volume dwarf galaxies
Dolphin, A. E.; Tully, R. Brent; Sharina, M. E. +9 more
We present surface photometry and metallicity measurements for 104 nearby dwarf galaxies imaged with the Advanced Camera for Surveys and Wide Field and Planetary Camera 2 aboard the Hubble Space Telescope. In addition, we carried out photometry for 26 galaxies of the sample and for Sextans B on images of the Sloan Digital Sky Survey. Our sample co…
Detection of a Hot Subdwarf Companion to the Be Star FY Canis Majoris
Gies, Douglas R.; Peters, Geraldine J.; Grundstrom, Erika D. +1 more
The rapid rotation of Be stars may be caused in some cases by past mass and angular momentum accretion in an interacting binary in which the mass donor is currently viewed as a small, hot subdwarf stripped of its outer envelope. Here we report on the spectroscopic detection of such a subdwarf in the Be binary system FY Canis Majoris from the analy…
Phyllosilicate and sulfate-hematite deposits within Miyamoto crater in southern Sinus Meridiani, Mars
Clark, R. N.; Arvidson, R. E.; Morris, R. V. +13 more
Orbital topographic, image, and spectral data show that sulfate- and hematite-bearing plains deposits similar to those explored by the MER rover Opportunity unconformably overlie the northeastern portion of the 160 km in diameter Miyamoto crater. Crater floor materials exhumed to the west of the contact exhibit CRISM and OMEGA NIR spectral signatu…