| Proposal ID | 014095 |
| Title | Transmission- to reflection-dominated spectral transitions in Seyfert 2 galaxies |
| Download Data Associated to the proposal | https://nxsa.esac.esa.int/nxsa-sl/servlet/data-action-aio?obsno=0140950101 |
| DOI | https://doi.org/10.5270/esa-k5scf6b |
| Principal Investigator, PI | Dr Matteo Guainazzi |
| Abstract | 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 Seyfert~2 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. |
| Publications |
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| Instrument | EMOS1, EMOS2, EPN, OM, RGS1, RGS2 |
| Temporal Coverage | 2002-12-29T21:53:24Z/2003-09-05T17:01:44Z |
| Version | 21.51_20241115_1113 |
| 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 | 2008-09-01T00:00:00Z |
| Last Update | 2026-07-09 |
| Keywords | "XMM-Newton", "unbiased sample", "total allocation time", "heavily obscured agn", "compton thick", "transmission dominated", "compton thick absorber", "optically defined", "convincingly explained", "sound statistical basis", "activity level", "XMM", "substantial fraction", "low activity", "xmm newton ao2", "seyfert 2s", "active nucleus covered", "reflection dominated seyfert" |
| Publisher And Registrant | European Space Agency |
| Credit Guidelines | European Space Agency, Dr Matteo Guainazzi, 2008, 'Transmission- to reflection-dominated spectral transitions in Seyfert 2 galaxies', 21.51_20241115_1113, European Space Agency, https://doi.org/10.5270/esa-k5scf6b |
| Rights | Data hosted in the ESA Space Science Archives are distributed under the CC BY-NC 3.0 IGO license. |