1,350 research outputs found
Search for GRB afterglows in the ROSAT all-sky survey
We report on the status of our search for X-ray afterglows of gamma-ray
bursts (GRBs) using the ROSAT all-sky survey data. The number of potential
X-ray afterglow candidates with respect to the expected number of beamed GRBs
allows to constrain the relative beaming angles of GRB emission and afterglow
emission at about 1-5 hrs after the GRB.Comment: 3 pages A&A style, 1 color ps-figure; To appear in A&A Suppl. Series,
Proc. of Rome 1998 GRB workshop, also available from
http://www.aip.de/~jcg/publis.htm
ROSAT All-Sky Survey observations of IRAS galaxies; I. Soft X-ray and far-infrared properties
The 120,000 X-ray sources detected in the RASS II processing of the ROSAT
All-Sky Survey are correlated with the 14,315 IRAS galaxies selected from the
IRAS Point Source Catalogue: 372 IRAS galaxies show X-ray emission within a
distance of 100 arcsec from the infrared position. By inspecting the structure
of the X-ray emission in overlays on optical images we quantify the likelihood
that the X-rays originate from the IRAS galaxy. For 197 objects the soft X-ray
emission is very likely associated with the IRAS galaxy. Their soft X-ray
properties are determined and compared with their far-infrared emission. X-ray
contour plots overlaid on Palomar Digitized Sky Survey images are given for
each of the 372 potential identifications. All images and tables displayed here
are also available in electronic form.Comment: accepted for publication in A&AS, complete version including all
figures and tables available at
http://www.rosat.mpe-garching.mpg.de/~bol/iras_rassI
Investigating ionized disc models of the variable narrow-line Seyfert 1 PG 1404+226
We investigate the use of relativistically blurred photoionized disc models
on an XMM-Newton observation of the Narrow Line Seyfert 1 galaxy PG 1404+226.
The model is designed to reproduce the radiation from the inner accretion disc
around a Kerr black hole, and is more successful at fitting the spectrum than
models based on a thermal soft excess. The source varies strongly over the
course of the observation, and the disc model works over all observed flux
states. We conclude that it is a useful tool in the study of certain quasars.Comment: 6 pages, 3 figures. Accepted for publication in MNRA
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