We report on a quasar with a steep soft 0.1-2.4 keV X-ray photon index based onROSAT PSPC observations. HB89 0102-272 exhibits a photon index of(6.55+-2.07). A second observation of the object confirms the steep photon indexof (6.40+-2.20). This is the steepest spectral energy distribution in the0.1-2.4 keV energy band from an extragalactic object reported so far. We intendto find out, whether other models can explain the ROSAT data. We show that anionized absorber can flatten the spectrum significantly. The 2.4-10 keV energydistribution will be determined for the first time. As the object is expected tobe more complex we ask for a 50 ks snapshot observation in order to determinethe significance of additional spectral components.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2009-12-05T02:20:07Z/2009-12-05T08:30:25Z
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 Thomas Boller, 2010, 'SQUARE_BRACKET_OPENHB89SQUARE_BRACKET_CLOSE 0102-272: a quasar with an extremely steep soft photon indexquestionMark', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-d8zxhw4
