With the aim of discovering more sources which change their appearance fromCompton--thin (if Seyfert 2s) or unabsorbed (if Seyfert 1s) toreflection--dominated, we propose to observe, for 10 ks each, four objects whichhave been proposed to be the optical counterparts of X--ray sources in theGrossan LMA HEAO1 catalog. The four candidate counterparts have been later onobserved with imaging X-ray instruments, and found on those occasions to be muchfainter. The XMM- Newton observations, if catching the sources at much brighterfluxes than during the previous hard X--ray imaging observations, would confirmtheir transient nature.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2004-06-02T14:52:45Z/2004-09-21T01:23:33Z
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, Prof GIORGIO MATT, 2005, 'SEARCHING FOR 'CHANGING LOOK. SEYFERT GALAXIES', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-c33dh8g
