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The central engines of radio-loud quasars
Ho, L. C.; Staubert, R.; Wang, J. -M.
We have assembled a sample of 37 radio-loud quasars that have been imaged with the Hubble Space Telescope in order to investigate their black hole masses, accretion rates, and the structure of their accretion disks. The black hole masses were estimated from the luminosities of the host galaxies, and the accretion powers were extrapolated from the …
A Point-Source Excess in Abell 1185: Intergalactic Globular Clusters?
Jordán, Andrés; Marzke, Ronald O.; Côté, Patrick +1 more
Deep imaging with WFPC2 and the Hubble Space Telescope has been used to search for a population of intergalactic globular clusters (GCs) belonging to A1185, a richness class I cluster at cz=9800 km s-1. The field is noteworthy in that contains no bright galaxies and yet is centered on the peak of the cluster's X-ray surface brightness d…
Test for Alfvén Wave Signatures in a Solar Coronal Hole
Moran, Thomas G.
Using spectral line observations to study minor ion motions in a solar coronal hole, a test was made for the presence of Alfvén waves. From this we conclude that the Alfvén wave flux into the upper portion of the hole is not significant. The SOHO/SUMER ultraviolet spectrograph was used to observe 22 coronal ions with masses ranging from 14mH<…
The nature of the prompt X-ray and radio emission from SN 2002ap
Ray, A.; Bhatnagar, S.; Chandra, P. +1 more
We report on the combined X-ray and radio observations of the type Ic SN 2002ap, using XMM-Newton TOO observation of M 74 and the Giant Metrewave Radio Telescope (GMRT). We account for the presence of a nearby source in the pre-supernova Chandra field of view in our measurements of the X-ray flux (0.3 - 10 KeV) 5.2 days after the explosion. The X-…
XMM-Newton light curves of the low-mass X-ray binary EXO 0748-676: Dips, eclipses, and bursts
Wijnands, R.; van den Berg, M.; Homan, J.
We present an analysis of XMM-Newton light curves of the dipping, bursting, and eclipsing low-mass X-ray binary EXO 0748-676, focusing on the variability on time scales of seconds to hours. The observed variability can be roughly divided in three types: dips, eclipses and bursts. We find that the appearance of the latter two, depends strongly on t…
X-ray and optical properties of X-ray sources in the 13hr XMM-Newton/Chandra deep survey
Page, M. J.; Sasseen, T.; Mason, K. O. +8 more
The 13hr XMM-Newton/Chandra deep survey is the first of two extremely deep XMM-Newton fields observed by the XMM-OM consortium. A 120 ks Chandra mosaic, covering 0.2 deg2, provides sensitive, confusion-free point source detection with sub-arcsecond positions, while the 200 ks XMM-Newton observation provides high quality X-ray spectrosco…
New Laboratory Spectra of Isolated β-SiC Nanoparticles: Comparison with Spectra Taken by the Infrared Space Observatory
Mutschke, H.; Henning, Th.; Klein, R. +1 more
We present new laboratory infrared spectra of matrix-isolated β-SiC nanoparticles, which perfectly match the band profile of the 11+ µm feature observed in carbon stars. The new laboratory spectra differ in the shape of the band profile from former measurements of SiC nanoparticles thanks to the matrix-isolation technique which allows to obt…
The Star Formation History of Galaxies Measured from Individual Pixels. I. The Hubble Deep Field North
Hopkins, Andrew M.; Csabai, István; Connolly, Andrew J. +6 more
We analyze the photometric information contained in individual pixels of galaxies in the Hubble Deep Field North (HDF-N) using a new technique, pixel-z, that combines predictions of evolutionary synthesis models with photometric redshift template fitting. Each spectral energy distribution template is a result of modeling of the detailed physical p…
Imprints from the solar cycle on the helium atom and helium pickup ion distributions
Fahr, H. J.; Bzowski, M.; Rucinski, D.
Neutral interstellar helium atoms penetrate into the solar system almost unaffected by gas-plasma interactions in the heliospheric interface region, and thus can be considered as carriers of original information on the basic parameters (like density, temperature, bulk velocity) of the Very Local Interstellar Medium (VLISM). Such information can no…
Explanatory supplement of the ISOGAL-DENIS Point Source Catalogue
Alard, C.; Blommaert, J. A. D. L.; Ganesh, S. +10 more
We present version 1.0 of the ISOGAL-DENIS Point Source Catalogue (PSC), containing more than 100 000 point sources detected at 7 and/or 15 mu m in the ISOGAL survey of the inner Galaxy with the ISOCAM instrument on board the Infrared Space Observatory (ISO). These sources are cross-identified, wherever possible, with near-infrared (0.8-2.2 mu m) …