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Can a Dusty Warm Absorber Model Reproduce the Soft X-Ray Spectra of MCG -6-30-15 and Markarian 766?
Kahn, Steven M.; Paerels, Frits; Behar, Ehud +8 more
XMM-Newton RGS spectra of MCG -6-30-15 and Mrk 766 exhibit complex discrete structure, which was interpreted in a paper by Branduardi-Raymont and coworkers as evidence for the existence of relativistically broadened Lyα emission from carbon, nitrogen, and oxygen, produced in the innermost regions of an accretion disk around a Kerr black hole. This…
Resolved Mid-Infrared Emission in the Narrow-Line Region of NGC 4151
Robinson, A.; De Buizer, James M.; Radomski, James T. +4 more
We present subarcsecond-resolution mid-infrared images of NGC 4151 at 10.8 and 18.2 µm. These images were taken with the University of Florida mid-IR camera/spectrometer OSCIR at the Gemini North 8 m telescope. We resolve emission at both 10.8 and 18.2 µm, extending ~3.5" across at a P.A. of ~60°. This coincides with the narrow-line re…
The Puzzling Dynamical Status of the Core of the Globular Cluster NGC 6752
Sabbi, E.; Possenti, A.; Origlia, L. +4 more
We have used high-resolution Hubble Space Telescope Wide Field Planetary Camera 2 and ground-based wide-field images to determine the center of gravity and construct an extended radial density and brightness profile of the cluster NGC 6752 including, for the first time, detailed star counts in the very inner region. The barycenter of the nine inne…
The First Deep Advanced Camera for Surveys Lyα Images of Local Starburst Galaxies
Östlin, Göran; Leitherer, Claus; Mas-Hesse, J. Miguel +2 more
We report the first results from a deep Lyα imaging program of local starburst galaxies with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. The two observed galaxies ESO 350-IG038 and SBS 0335-052 have luminosities similar to those of the Magellanic Clouds but differ in their chemical composition. ESO 350-IG038 has an oxygen …
XMM-Newton and Chandra Observations of the Galaxy Group NGC 5044. I. Evidence for Limited Multiphase Hot Gas
Buote, David A.; Brighenti, Fabrizio; Mathews, William G. +1 more
Using new XMM and Chandra observations, we present an analysis of the temperature structure of the hot gas within a radius of 100 kpc of the bright nearby galaxy group NGC 5044. A spectral deprojection analysis of data extracted from circular annuli reveals that a two-temperature model (2T) of the hot gas is favored over single-phase or cooling fl…
A Hubble Space Telescope Wide Field Planetary Camera 2 Survey for Brown Dwarf Binaries in the α Persei and Pleiades Open Clusters
Bouy, Hervé; Barrado y Navascués, David; Martín, Eduardo L. +2 more
We present the results of a high-resolution imaging survey for brown dwarf binaries in two open clusters. The observations were carried out with the Wide Field Planetary Camera 2 on board the Hubble Space Telescope. Our sample consists of eight brown dwarf candidates in α Persei and 25 brown dwarf candidates in the Pleiades. We have resolved four …
Age Dependence of the Vega Phenomenon: Observations
Waters, L. B. F. M.; Dominik, C.; Waelkens, C. +1 more
We study the time dependency of Vega-like excesses using infrared studies obtained with the imaging photopolarimeter ISOPHOT on board the Infrared Space Observatory. We review the different studies published on this issue and critically check and revise ages and fractional luminosities in the different samples. The conclusions of our study differ …
Chandra Observations of QSO 2237+0305
Agol, E.; Garmire, G. P.; Bautz, M. W. +2 more
We present the observations of the gravitationally lensed system QSO 2237+0305 (Einstein Cross) performed with the Advanced CCD Imaging Spectrometer on board the Chandra X-Ray Observatory on 2000 September 6 and on 2001 December 8 for 30.3 and 9.5 ks, respectively. Imaging analysis resolves the four X-ray images of the Einstein Cross. A possible f…
The Baldwin Effect and Black Hole Accretion: A Spectral Principal Component Analysis of a Complete Quasar Sample
Laor, Ari; Wills, D.; Shang, Zhaohui +4 more
We have performed a spectral principal component analysis (SPCA) for an essentially complete sample of 22 low-redshift QSOs with spectral data from Lyα to Hα. SPCA yields a set of independent principal component spectra, each of which represents a set of relationships among QSO continuum and line properties. We find three significant principal com…
Shaping Proto-Planetary and Young Planetary Nebulae with Collimated Fast Winds
Lee, Chin-Fei; Sahai, Raghvendra
Using two-dimensional hydrodynamical simulations, we investigate the interaction of a collimated fast wind (CFW) interacting with a spherical asymptotic giant branch (AGB) wind as the mechanism for shaping proto-planetary nebulae (PPNs) and young planetary nebulae. In particular, we compare our simulations with the observations of an evolved PPN w…