Studies of heavily obscured active galactic nuclei (AGN) suggest that the torusthat causes the obscuration is patchy, rather than uniform. The line-of-sightcolumn density (NH_los) of the obscuring material should vary over weeks tomonths, but such an evidence has been observed only in a few X-ray detected AGN,due to lack of large samples of heavily obscured AGN with multi-epochobservations. We propose for a XMM monitoring of NGC 1358, a nearby Comptonthick (CT-) AGN with small torus covering factor and NH_los significantly largerthan the torus average column density. Through this monitoring, we expect tomeasure significant variability in NH_los and detect a transition from CT- toCompton thin, thus improving our knowledge on the properties of the obscuring material surrounding AGN.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2021-02-25T00:25:39Z/2021-02-25T10:30:39Z
Version
18.02_20200221_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 Stefano Marchesi, 2022, 'A XMM-Newton monitoring of a candidate changing-look Compton thick AGN', 18.02_20200221_1200, European Space Agency, https://doi.org/10.57780/esa-89hpnik
