Proposal ID | 010366 |
Title | Are there X-ray quiet quasars |
Download Data Associated to the proposal | https://nxsa.esac.esa.int/nxsa-sl/servlet/data-action-aio?obsno=0103660101 |
DOI | https://doi.org/10.5270/esa-7ab43zm |
Principal Investigator, PI | Dr Bernd Aschenbach |
Abstract | GT-The X-ray-to-optical energy distribution of quasars, alpha_ox, is requiredto relate the quasar statistics, evolution and luminosity function in the twowavebands and to understand its broad band emission. In a recent study ofradio-quiet quasars from ROSAT observations there is a small number of objectsshowing very weak X-ray emission compared to their optical luminosity. Thenature of these X-ray quiet quasars is unknown and it is not clear whether theyare the X-ray quiet extremes of a continous distribution or a distinct class ofobjects. XMM observations seem to be the only way to understand this newpopulation of quasars and to distinguish different explanations for the unknownphysical nature of these objects. |
Publications |
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Instrument | EMOS1, EMOS2, EPN, OM, RGS1, RGS2 |
Temporal Coverage | 2000-11-04T23:35:48Z/2002-07-10T15:55:52Z |
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 | 2003-08-09T00:00:00Z |
Last Update | 2025-01-27 |
Keywords | "broad band emission", "xray quiet extremes", "optical luminosity", "luminosity function", "ROSAT", "optical energy distribution", "weak xray emission", "radio quiet quasars", "xray quiet quasars", "XMM", "continous distribution", "quasar statistics", "distinct class" |
Publisher And Registrant | European Space Agency |
Credit Guidelines | European Space Agency, Dr Bernd Aschenbach, 2003, 'Are there X-ray quiet quasars', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-7ab43zm |