|Title||The Nature of Soft X-Ray Weak Quasars|
|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|
|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.
|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|