| Name | 015061 |
| Title | The Nature of Soft X-Ray Weak Quasars |
| URL | https://nxsa.esac.esa.int/nxsa-sl/servlet/data-action-aio?obsno=0150610101 |
| DOI | https://doi.org/10.5270/esa-zsf5xnr |
| 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 |
| Temporal Coverage | 2002-11-03T01:06:03Z/2003-05-14T19:52:57Z |
| Version | 17.56_20190403_1200 |
| 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. |
| Creator Contact | https://www.cosmos.esa.int/web/xmm-newton/xmm-newton-helpdesk |
| Date Published | 2004-06-04T00:00:00Z |
| 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 |