Search Publications
The Dusty Nebula Surrounding HR Car: A Spitzer View
Umana, G.; Fazio, G. G.; Hora, J. L. +3 more
We present mid-IR observations of the Galactic Luminous Blue Variable (LBV) HR Car and its associated nebula carried out with the Spitzer Space Telescope using both Infrared Array Camera and Infrared Spectrograph, as part of a GTO program aimed to study stellar ejecta from evolved stars. Our observations reveal a rich mid-IR spectrum of the inner …
Toward Reconstruction of Coronal Mass Ejection Density from Only Three Points of View
Morgan, H.; Frazin, R. A.; Manchester, W. B., IV +2 more
Understanding the structure of coronal mass ejections (CMEs) is one of the primary challenges in solar astrophysics. White-light coronagraphs make images of line-of-sight projections of the CME electron density (Ne ). The combination of the coronagraphs on the STEREO and SOHO spacecraft provides three simultaneous viewpoints that vary i…
The UV-Mid-IR Spectral Energy Distribution of a z = 1.7 Quasar Host Galaxy
Kochanek, C. S.; Assef, R. J.; Ross, N. R. +2 more
We have measured the spectral energy distribution (SED) of the host galaxy of the zs = 1.7 gravitationally lensed quasar SDSS J1004+4112 from 0.44-8.0 µm (0.16-3.0 µm in the rest frame). The large angular extent of the lensed images and their separation from the central galaxy of this cluster lens allows the images to be res…
Color Bimodality in M87 Globular Clusters
Zepf, Stephen E.; Lauer, Tod R.; Waters, Christopher Z. +1 more
We present an analysis of a 50 orbit Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) observation of the M87 globular cluster system. We use the extraordinary depth of this data set to test whether the colors and magnitudes show evidence for a mass-metallicity relation in globular cluster populations. We find only a weak or absent re…
Discovery of Fog at the South Pole of Titan
Brown, M. E.; Chen, C.; Ádámkovics, M. +1 more
While Saturn's moon Titan appears to support an active methane hydrological cycle, no direct evidence for surface-atmosphere exchange has yet appeared. The indirect evidence, while compelling, could be misleading. It is possible, for example, that the identified lake features could be filled with ethane, an involatile long-term residue of atmosphe…
The X-ray Detectability of Electron Beams Escaping from the Sun
Krucker, Säm; Lin, Robert P.; Saint-Hilaire, Pascal +1 more
We study the detectability and characterization of electron beams as they leave their acceleration site in the low corona toward interplanetary space through their nonthermal X-ray bremsstrahlung emission. We demonstrate that the largest interplanetary electron beams (gsim1035 electrons above 10 keV) can be detected in X-rays with curre…
The Structure and Origin of Solar Plumes: Network Plumes
Wilhelm, K.; Gabriel, A.; Tison, E. +1 more
This study is based upon plumes seen close to the solar limb within coronal holes in the emission from ions formed in the temperature region of 1 MK, in particular, the band of Fe IX 171 Å from EIT on the Solar and Heliospheric Observatory. It is shown, using geometric arguments, that two distinct classes of structure contribute to apparently simi…
ChaMPlane Deep Galactic Bulge Survey. I. Faint Accretion-driven Binaries in the Limiting Window
van den Berg, Maureen; Grindlay, Jonathan E.; Hong, Jae Sub
We have carried out a deep X-ray and optical survey with Chandra and HST of low-extinction regions in the Galactic bulge. Here we present the results of a search for low-luminosity (LX lsim 1034 erg s-1) accreting binaries among the Chandra sources in the region closest to the Galactic center, at an angular offset …
Newly Identified Star Clusters in M33. II. Radial Hubble Space Telescope/Advanced Camera for Surveys Fields
Sarajedini, Ata; Holtzman, Jon A.; Garnett, Donald R. +1 more
We present integrated photometry and color-magnitude diagrams (CMDs) for 161 star clusters in M33, of which 115 were previously uncataloged, using the Advanced Camera For Surveys Wide Field Channel onboard the Hubble Space Telescope. The integrated V-band magnitudes of these clusters range from MV ~-9 to as faint as MV ~-4, e…
SCP 06F6: A Carbon-rich Extragalactic Transient at Redshift z sime 0.14?
Wheatley, Peter J.; Gänsicke, Boris T.; Marsh, Thomas R. +1 more
We show that the spectrum of the unusual transient SCP 06F6 is consistent with emission from a cool, optically thick and carbon-rich atmosphere if the transient is located at a redshift of z ≈ 0.14. The implied extragalactic nature of the transient rules out novae, shell flashes, and V838 Mon-like events as causes of the observed brightening. The …