Search Publications
The X-Ray Properties of M101 ULX-1 = CXOKM101 J140332.74+542102
Mukai, K.; Kuntz, K. D.; Corbet, R. H. D. +2 more
We report our analysis of X-ray data on M101 ULX-1, concentrating on high-state Chandra and XMM-Newton observations. We find that the high state of M101 ULX-1 may have a preferred recurrence timescale. If so, the underlying clock may have periods around 160 or 190 days, or possibly around 45 days. Its short-term variations resemble those of X-ray …
Type 2 Counterparts of Narrow-Line Seyfert 1 Galaxies
Dewangan, G. C.; Griffiths, R. E.
Unified models based on viewing angle successfully explain the observed differences between type 1 and type 2 Seyfert galaxies. The existence of a range in accretion rates (m˙~0.001-1) relative to the Eddington rate (from broad-line Seyfert 1's to narrow-line Seyfert 1's, or NLS1's) and the unification of Seyfert galaxies imply that there must be …
Fluorescent Molecular Hydrogen Emission in IC 63: FUSE, Hopkins Ultraviolet Telescope, and Rocket Observations
France, K.; Feldman, P. D.; Andersson, B. -G. +1 more
We present far-ultraviolet observations of IC 63, an emission/reflection nebula illuminated by the B0.5 IV star γ Cas, located 1.3 pc from the nebula. Molecular hydrogen fluorescence was detected first in IC 63 by IUE and later at shorter wavelengths by ORFEUS. Here we present Far Ultraviolet Spectroscopic Explorer (FUSE) observations toward three…
Cl 1205+44: A Fossil Group at z = 0.59
Romer, A. K.; Adami, C.; Durret, F. +6 more
This is a report of Chandra, XMM-Newton, Hubble Space Telescope, and Astrophysical Research Consortium telescope observations of an extended X-ray source at z=0.59. The apparent member galaxies range from spiral to elliptical, and are all relatively red (i'-Ks about 3). We interpret this object to be a fossil group based on t…
Merging Galaxies in GOODS-S: First Extragalactic Results from Keck Laser Adaptive Optics
Koo, D. C.; Le Mignant, D.; Wright, S. A. +15 more
The Center for Adaptive Optics Treasury Survey aims to combine deep Hubble Space Telescope (HST) images in the optical with deep Keck adaptive optics (AO) data in the near-infrared (NIR) to study distant galaxies, active galactic nuclei, and supernovae. We recently achieved an important new milestone by securing the first Keck laser guide star AO …
Protostars, Dust Globules, and a Herbig-Haro Object in the LMC Superbubble N51D
Gruendl, R. A.; Smith, R. C.; Gordon, K. D. +9 more
Using Spitzer Space Telescope and Hubble Space Telescope observations of the superbubble N51D, we have identified three young stellar objects (YSOs) in dust globules and made the first detection of a Herbig-Haro object outside the Galaxy. The spectral energy distributions of these YSOs suggest young massive stars with disk, envelope, and outflow c…
XMM-Newton Observations of the M31 Northern Disk: Properties of Selected X-Ray Sources and Unresolved Emission
Mason, Keith; Trudolyubov, Sergey; Kotov, Oleg +2 more
We present the results of an XMM-Newton survey of the northern part of M31 disk. The X-ray properties of the 37 brightest sources are studied in detail. Combining the results of X-ray analysis with available data at other wavelengths, we were able to identify 19 out of 37 sources. Two sources in our sample were previously unknown: the hard X-ray s…
Probing Multiple Sight Lines through the SN 1006 Remnant by Ultraviolet Absorption Spectroscopy
Long, Knox S.; Fesen, Robert A.; Winkler, P. Frank +1 more
Absorption-line spectroscopy is an effective probe for cold ejecta within a supernova remnant (SNR), provided that suitable background UV sources can be identified. For the SN 1006 remnant we have identified four such sources, in addition to the much-studied Schweitzer-Middleditch (SM) star. We have used STIS on the Hubble Space Telescope to obtai…
The Nonhomologous Nature of Solar Diameter Variations
Basu, Sarbani; Sofia, Sabatino; Demarque, Pierre +2 more
We show in this Letter that the changes of the solar diameter in response to variations of large-scale magnetic fields and turbulence are not homologous. For the best current model, the variation at the photospheric level is over 1000 times larger than the variation at a depth of 5 Mm, which is about the level at which f-mode solar oscillations de…
Absolute Proper Motion of the Canis Major Dwarf Galaxy Candidate
Rix, Hans-Walter; Peñarrubia, Jorge; Girard, Terrence M. +4 more
We have measured the absolute proper motion of the candidate Canis Major dwarf galaxy (CMa), at (l,b)=(240°,-8°). Likely main-sequence stars in CMa have been selected from a region in the color-magnitude diagram that has very little contamination from known Milky Way components. We obtain µlcosb=-1.47+/-0.37 and µb