Quasars exhibit X-ray emission proportional to their UV emission, and most X-rayweak objects are absorbed. The exception may be PHL 1811, a nearby quasar thatis 25--100 times X-ray fainter than expected, but has a steep and variable X-rayspectrum suggesting a direct view of the central engine. It also has unusual UVemission line properties that are consistent with its X-ray weak SED. Searchesfor PHL 1811 analogs, chosen by their UV spectral properties, find objects thatare X-ray weak but which have hard X-ray spectra, suggesting absorption.Previous X-ray observations of PHL 1811 extended only to 6 keV, so a highlyabsorbed component can.t be ruled out. We propose coordinated XMM- Newton andNuSTAR observations to see whether PHL 1811 is intrinsically normal and highly absorbed.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2015-11-29T09:38:07Z/2015-11-30T02:08:07Z
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 Karen Leighly, 2016, 'Unifying X-ray Weak Quasars: Is there a Highly Absorbed Component in PHL 1811questionMark', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-lggb7q6
