Issue |
A&A
Volume 436, Number 2, June III 2005
|
|
---|---|---|
Page(s) | 465 - 468 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361:20042303 | |
Published online | 30 May 2005 |
Research Note
The EUV variability of the luminous QSO HS 1700+6416
1
Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany e-mail: dreimers@hs.uni-hamburg.de
2
STScI, 3700 San Martin Dr. Baltimore, MD 21218, USA
3
CASA, Department of Astrophysical and Planetary Science, University of Colorado, Boulder, CO 80309, USA
Received:
3
November
2004
Accepted:
27
February
2005
We report on the first observations of variations in UV
(intrinsic EUV 330 Å) flux of the luminous QSO HS 1700+6416 () over a decade. The amplitude of variations increases from ±0.1 mag in the optical (R) to up to a factor of 3 at 1250 Å. This
is apparently an extension of the increase in amplitude of
variations towards shorter wavelengths observed with IUE in low z AGN
(Paltani & Courvoisier 1996) to the EUV. The time-scale for
variations with the largest amplitudes is ≥1/2 yr to years. We
briefly discuss the consequences of the observed variations on the
ionizing metagalactic UV background.
Key words: galaxies: clusters: individual HS 1700+6416 / galaxies: quasars: general
© ESO, 2005
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