About 10% of the quasars are soft X-ray-weak: its X-ray emission is by a factor10-30 fainter than in typical quasars. Different observational parameterssuggest that absorption is the primary cause of their X-ray weakness, but auniform absorbing screen cannot explain the X-ray and ultraviolet emission. Ourprevious XMM-Newton observations of three quasars confirm that their weakness isrelated to absorption. However, our data show an absorbing column density andionization parameter, which are much higher than detected for other AGNs. Wepropose to observe the last two outstanding X-ray weak quasars of the completesample of Brand, Laor and Wills et al. (2000), which will allow to rigorouslystudy the X-ray absorption scenario in X-ray weak quasars.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2005-06-15T06:26:44Z/2005-06-15T15:16:56Z
Version
17.56_20190403_1200
Mission Description
The European Space Agencys (ESA) X-ray Multi-Mirror Mission (XMM-Newton) was launched by an Ariane 504 on December 10th 1999. XMM-Newton is ESAs 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 Earths 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.
European Space Agency, Dr Norbert Schartel, 2006, 'The Nature of Soft X-Ray Weak Quasars', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-u8qj3rp
