We propose seven short observations of X-ray weak quasars, with the aim ofunderstanding the origin of their low X-ray to optical ratio. The sources belongto the spectroscopically selected Hamburg Quasar Survey, and have been observedwith Chandra and in the optical. They show unusual optical properties (most ofthem have a red continuum and very high EW broad emission lines), while thenature of their X-ray weakness (intrinsic or due to absorption ?) is not yetclear, because of the low signal-to-noise of the Chandra spectra. Four shortobservations with XMM-Newton gave the answer for four sources, showingabsorption in two cases, and an unabsorbed spectrum in the other two. This showsthat XMM-Newton can unveil the nature of the X-ray emission of these sources.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2006-06-01T16:44:59Z/2007-05-04T11:03:23Z
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 Guido Risaliti, 2008, 'X-ray weak broad-line quasars: absorption or intrinsic X-ray weakness', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-53v0hg6
