Reflection-dominated Seyfert 2 galaxies are usually interpreted in terms of anactive nucleus covered by a Compton-thick absorber. However, recentserendipitously discovered transitions between reflection- (R) andtransmission-dominated (T) states are more convincingly explained as changes inthe activity level of the AGN. If this is true, a substantial fraction of RSeyfert 2s may actually correspond to low-activity states, rather than toheavily obscured AGN. We propose to observe an optically defined, complete andunbiased sample of Compton-thick Seyfertvirgul2 galaxies during the XMM-Newton AO2,to measure on a sound statistical basis the rate of R to T transitions. Werequest to observe 8 objects for a total allocation time of 100 ks.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2002-12-29T21:53:24Z/2003-09-05T17:01:44Z
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 Matteo Guainazzi, 2008, 'Transmission- to reflection-dominated spectral transitions in Seyfert 2 galaxies', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-k5scf6b
