|Title||X-ray weak broad-line quasars: absorption or intrinsic X-ray weakness|
|Author||Mr Guido Risaliti|
|Description||We propose to observe a sample of 20 soft X-ray weak, optically red quasars, discovered by the Hamburg Quasar Survey. The lack of detection in the ROSAT PSPC, despite their relatively bright optical emission make them a peculiar class of quasars, classified as type 1 in the optical but type 2 in the X-rays. Establishing the X-ray properties of these objects is important for (1) the X-ray background synthesis models (they could be the missing "QSO2s"), (2) the unified models (they challenge the traditional torus model) and (3) the long debated problem on the discrepancy between optical and X-ray luminosity functions. XMM provides the unique opportunity to observe a well defined sample of such sources and measure their absorption column density in many cases.|
|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, 2005-01-20T00:00:00Z, 014874, 17.56_20190403_1200. https://doi.org/10.5270/esa-zrbak7m|