A dataset provided by the European Space Agency

Name 015061
Title The Nature of Soft X-Ray Weak Quasars


DOI https://doi.org/10.5270/esa-zsf5xnr
Author Dr Norbert Schartel
Description About 1-10 of the quasars can be classified as soft X-ray-weak, whose X-ray emission is by a factor 10-30 fainter than in typical quasars. They show a strong correlation between alpha OX and the C IV absorption equivalent width, which suggest that absorption is the primary cause of their soft X-ray- weakness. But the shape of the correlation can not be reproduced by an uniform screen covering both the X-ray source and the ultraviolet emission. Therefore either the UV and X-ray absorbers are not identical (warm absorber, partly covered, only scattered flux) or the X-ray weakness is due to a peculiar property of the nuclear emission, as extreme variability or unusual steepness.
Publication No observations found associated with the current proposal
Instrument EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage 2002-11-03T01:06:03Z/2003-05-14T19:52:57Z
Version 17.56_20190403_1200
Mission Description The European Space Agency's (ESA) X-ray Multi-Mirror Mission (XMM-Newton) was launched by an Ariane 504 on December 10th 1999. XMM-Newton is ESA's second cornerstone of the Horizon 2000 Science Programme. It carries 3 high throughput X-ray telescopes with an unprecedented effective area, and an optical monitor, the first flown on a X-ray observatory. The large collecting area and ability to make long uninterrupted exposures provide highly sensitive observations.
Since Earth's atmosphere blocks out all X-rays, only a telescope in space can detect and study celestial X-ray sources. The XMM-Newton mission is helping scientists to solve a number of cosmic mysteries, ranging from the enigmatic black holes to the origins of the Universe itself. Observing time on XMM-Newton is being made available to the scientific community, applying for observational periods on a competitive basis.
Creator Contact https://www.cosmos.esa.int/web/xmm-newton/xmm-newton-helpdesk
Date Published 2004-06-04T00:00:00Z
Publisher And Registrant European Space Agency
Credit Guidelines European Space Agency, 2004-06-04T00:00:00Z, 015061, 17.56_20190403_1200. https://doi.org/10.5270/esa-zsf5xnr