Search Publications
Hot Gas in the Circumstellar Bubble S308
Guerrero, Martín A.; Chu, You-Hua; Gruendl, Robert A. +2 more
S308 is a circumstellar bubble blown by the WN4 star HD 50896. It is one of the only two single-star bubbles that show detectable diffuse X-ray emission. We have obtained XMM-Newton EPIC observations of the northwest quadrant of S308. The diffuse X-ray emission shows a limb-brightened morphology, with a clear gap extending from the outer edge of t…
Evidence for an Intermediate-Age, Metal-rich Population of Globular Clusters in NGC 4365
Forbes, Duncan A.; Brodie, Jean P.; Beasley, Michael A. +4 more
We present spectroscopy for globular clusters (GCs) in the elliptical galaxy NGC 4365, obtained with the Low-Resolution Imaging Spectrograph on the Keck I telescope. Previous studies have shown that the optical color distribution of GCs in NGC 4365 lacks the bimodal structure that is common in globular cluster systems, showing only a single broad …
Chandra Observation of the Edge-on Galaxy NGC 3556 (M108): Violent Galactic Disk-Halo Interaction Revealed
Wang, Q. Daniel; Irwin, Judith A.; Chaves, Tara
We present a 60 ks Chandra ACIS-S observation of the isolated edge-on spiral galaxy NGC 3556, together with a multiwavelength analysis of various discrete X-ray sources and diffuse X-ray features. Among 33 discrete X-ray sources detected within the IB=25 mag arcsec-2 isophote ellipse of the galaxy, we identify a candidate for…
X-Ray Evidence of a Buried Active Galactic Nucleus in UGC 5101
Nakagawa, Takao; Imanishi, Masatoshi; Terashima, Yuichi +1 more
We present X-ray observations of the ultraluminous infrared galaxy, UGC 5101, thought to contain a buried active galactic nucleus (AGN) based on observations in other wave bands. We detected an absorbed hard component at greater than 3 keV, as well as soft emission in the energy range 0.5-2 keV. The soft X-ray component, possibly due to a modestly…
The Canada-UK Deep Submillimeter Survey. VII. Optical and Near-Infrared Identifications for the 14 Hour Field
Clements, D. L.; Dunne, L.; Eales, S. +5 more
We present the multiwavelength identifications for 23 sources in the Canada-UK Deep Submillimeter Survey (CUDSS) 14h field. The identifications have been selected on the basis of radio and near-infrared data, and we argue that, to our observational limits, both are effective at selecting the correct counterparts of the SCUBA sources. We…
X-Ray Spectroscopy of the Low-Mass X-Ray Binaries 2S 0918-549 and 4U 1543-624: Evidence for Neon-rich Degenerate Donors
Chakrabarty, Deepto; Juett, Adrienne M.
We present high-resolution spectroscopy of the neutron star/low-mass X-ray binaries 2S 0918-549 and 4U 1543-624 with the High Energy Transmission Grating Spectrometer on board the Chandra X-Ray Observatory and the Reflection Grating Spectrometer on board XMM-Newton. Previous low-resolution spectra of both sources showed a broad, linelike feature a…
Simultaneous Ultraviolet and X-Ray Spectroscopy of the Seyfert 1 Galaxy NGC 5548. I. Physical Conditions in the Ultraviolet Absorbers
Kaastra, J. S.; Turner, T. J.; Kraemer, S. B. +9 more
We present new UV spectra of the nucleus of the Seyfert 1 galaxy NGC 5548, which we obtained with the Space Telescope Imaging Spectrograph at high spectral resolution, in conjunction with simultaneous Chandra X-Ray Observatory spectra. Taking advantage of the low UV continuum and broad emission-line fluxes, we have determined that the deepest UV a…
Hubble Space Telescope Observations of High-Velocity Lyα and Hα Emission from Supernova Remnant 1987A: The Structure and Development of the Reverse Shock
Filippenko, Alexei V.; Pun, C. S. J.; Garnavich, Peter +18 more
We present two-dimensional line profiles of high-velocity (~+/-12,000 km s-1) Lyα and Hα emission from supernova remnant 1987A obtained with the Space Telescope Imaging Spectrograph between 1997 September and 2001 September (days 3869-5327 after the explosion). This emission comes from hydrogen in the debris that is excited and ionized …
The Ionized Gas and Nuclear Environment in NGC 3783. III. Detection of a Decreasing Radial Velocity in an Intrinsic Ultraviolet Absorber
Kaiser, Mary Elizabeth; Brandt, W. N.; Kaspi, Shai +14 more
We report an intrinsic absorber with decreasing outflow velocity in the Seyfert 1 galaxy NGC 3783. This is the first detection of a change in radial velocity in an outflow associated with a Seyfert galaxy. These results are based on measurements from 18 observations with the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope, o…
Measuring σ8 with Cluster Lensing: Biases from Unrelaxed Clusters
Smith, Graham P.; Smail, Ian; Kneib, Jean-Paul +3 more
We use gravitational lens models and X-ray spectral analysis of 10 X-ray-luminous galaxy clusters at z~=0.2 to study the impact of cluster substructure on attempts to normalize the matter power spectrum. We estimate that unrelaxed clusters are 30% hotter than relaxed clusters, causing σ8 to be overestimated by 20% if the cluster selecti…