| Proposal ID | 040661 |
| Title | X-ray weak broad-line quasars: absorption or intrinsic X-ray weakness |
| Download Data Associated to the proposal | https://nxsa.esac.esa.int/nxsa-sl/servlet/data-action-aio?obsno=0406610101 |
| DOI | https://doi.org/10.5270/esa-53v0hg6 |
| Principal Investigator, PI | Dr Guido Risaliti |
| Abstract | 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. |
| Publications |
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| 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. |
| Creator Contact | https://www.cosmos.esa.int/web/xmm-newton/xmm-newton-helpdesk |
| Date Published | 2008-05-31T00:00:00Z |
| Last Update | 2025-01-27 |
| Keywords | "chandra spectra", "low xray", "unabsorbed spectrum", "red continuum", "hamburg quasar survey", "xmm newton", "XMM-Newton", "xray weakness", "xray emission", "optical ratio", "XMM", "optical properties", "low signal", "xray weak quasars", "sources belong" |
| Publisher And Registrant | European Space Agency |
| Credit Guidelines | 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 |