Citations Only: Recent submissions
Now showing items 941-960 of 990
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A direct image of the obscuring disk surrounding an active galactic nucleus
(Nature, 1997-08-28)Active galactic nuclei (AGN) are generally accepted to be powered by the release of gravitational energy in a compact accretion disk surrounding a massive black hole. Such disks are also necessary to collimate powerful ... -
Refining Chandra/ACIS subpixel event repositioning using a backside illuminated CCD model
(Astrophysical Journal, 2003-06-10)Subpixel event repositioning (SER) techniques have been demonstrated to significantly improve the already unprecedented spatial resolution of Chandra X-ray imaging with the Advanced CCD Imaging Spectrometer (ACIS). Chandra ... -
Chandra/ACIS subpixel event repositioning. II. Further refinements and comparison between backside and front-side illuminated X-ray CCDs
(Astrophysical Journal, 2004-08-01)We further investigate subpixel event repositioning (SER) algorithms in application to Chandra X-ray Observatory (CXO) CCD imaging. SER algorithms have been applied to backside illuminated (BI) Advanced CCD Imaging ... -
An X-ray outburst from the rapidly accreting young star that illuminates McNeil's Nebula
(Nature, 2004-07-22)Young, low-mass stars are luminous X-ray sources1 whose powerful X-ray flares^(2-6) may exert a profound influence over the process of planet formation^(7). The origin of such emission is uncertain. Although many or ... -
X-ray properties of B2 1028+313: a quasar at the center of the Abell cluster A1030
(American Astronomical Society, 1999-01-01)X-ray observationswith the ROSATHRI and with ASCA are presented for the nearby radio quasar B2 1028+313, which is located in the cD galaxy at the center of the Abell cluster A1030. We also analyze archival ROSAT ... -
Constraints on ultraviolet absorption in the intracluster medium of Abell 1030
(Astrophysical Journal, 1998-12-01)We present results from an extensive HST spectroscopic search for UV absorption lines in the spectrum of the quasar B2 1028+313, which is associated with the central dominant galaxy in the cluster Abell 1030 (z=0.178). ... -
A comparative HST imaging study of the host galaxies of radio-quiet quasars, radio-loud quasars and radio galaxies: I
(Blackwell Publishing, 1999-09)We present the first results from a major HST WFPC2 imaging study aimed at providing the first statistically meaningful comparison of the morphologies, luminosities, scalelengths and colours of the host galaxies of radio-quiet ... -
The Radio-optical jet in NGC 3862 from parsec to sub-kiloparsec scales
(Astrophysical Journal, 1999-03-01)We have observed the radio source in NGC 3862 (3C 264) simultaneously with the European VLBI network and the MERLIN arrays, obtaining detailed images of its radio structure from parsec to subkiloparsec scales. 3C 264 shows ... -
The extended blue continuum and line emission around the Central Radio Galaxy in Abell 2597
(American Astronomical Society, 1999-11-10)We present results from detailed imaging of the centrally dominant radio elliptical galaxy in the cooling flow cluster Abell 2597, using data obtained with the Wide Field and Planetary Camera 2 (WFPC2) on the Hubble Space ... -
A NICMOS imaging study of high-z quasar host galaxies
(Blackwell Publishing, 2001-10)We present the first results from a major Hubble Space Telescope programme designed to investigate the cosmological evolution of quasar host galaxies from z~=2 to the present day. Here we describe J and H-band NICMOS ... -
Quasars, their host galaxies, and their central black holes
(Blackwell Publishing, 2003-04-09)We present the final results from our deep HST imaging study of the host galaxies of radio-quiet quasars (RQQs), radio-loud quasars (RLQs) and radio galaxies (RGs). We describe and analyze new WFPC2 R-band observations for ... -
HI absorption in the gigamaser galaxy TXS 2226-184 and the relation between HI absorption and water emission
(American Astronomical Society, 2002-07-20)We report on the discovery of H i in absorption toward the gigamaser galaxy TXS 2226-184 using the Very Large Array. The absorption appears to consist of two components—one with a width of 125 km s^-1 and one broader (420 ... -
The host galaxies of luminous quasars
(Blackwell Publishing, 2004-11)We present the results of a deep HST/WFPC2 imaging study of 17 quasars at z~=0.4, designed to determine the properties of their host galaxies. The sample consists of quasars with absolute magnitudes in the range −24 ≥ MV ... -
Star formation in hosts of young radio galaxies
(QSO Hosts: Evolution and Environment, 2005-08)We present near ultraviolet imaging with the Hubble Space Telescope Advanced Camera for Surveys, targeting young radio galaxies (Gigahertz Peaked Spectrum and Compact Steep Spectrum sources), in search of star formation ... -
The jet and circumnuclear environment of 3C 293
(Astrophysical Journal, 2006-03-01)We present the new HST near-infrared polarimetry, broad and narrow-band imaging, and MERLIN 4.5GHz Multi-Frequency Synthesis radio imaging of 3C 293, a unique radio galaxy whose host is an obvious merger remnant, in an ... -
The warped nuclear disk of radio galaxy 3C 449
(Astrophysical Journal, 2006)Among radio galaxies containing nuclear dust disks, the bipolar jet axis is generally observed to be perpendicular to the disk major axis. The FR I radio source 3C 449 is an outlier to this statistical majority, as it ...