|Title||Weak Line Quasars at High Redshift: Extremely High Accretion Rate Sources?|
|Author||Prof Ohad Shemmer|
|Description||The Sloan Digital Sky Survey has discovered a remarkable group of ~100 quasars with extremely weak emission lines in their rest-frame optical-UV spectra. We propose to extend our XMM-Newton observations of such sources and obtain imaging spectroscopy of six quasars of this class with a total exposure time of 128 ks, providing ~1000 photons per source. This will enable an accurate measurement of the hard-X-ray photon index required for a robust determination of the accretion rate in each source. Steep spectral slopes will indicate that high accretion rates may be responsible for the intrinsic weakness of the optical-UV emission lines. The proposed observations will lead to new insights about the accretion process and broad emission line formation in all active galactic nuclei.|
|Publication||XMM-Newton publication statistics . Ness, J.-U., Parmar, A. N., et all. . AN . 335-210 . 2014 . 2014AN....335..210N ,
The Million Optical - Radio-X-ray Associations (MORX) Catalogue . Flesch, Eric W., . PASA . 33-52 . 2016 . 2016PASA...33...52F ,
Steep Hard-X-Ray Spectra Indicate Extremely High Accretion Rates in Weak Emission-line Quasars . Marlar, Andrea, Shemmer, Ohad, et all. . ApJ . 865-92 . 2018 . 2018ApJ...865...92M ,
|Instrument||EMOS1, EMOS2, EPN, OM, RGS1, RGS2|
|Mission Description||The European Space Agency's (ESA) X-ray Multi-Mirror Mission (XMM-Newton) was launched by an Ariane 504 on December 10th 1999. XMM-Newton is ESA's 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 Earth's 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.
|Publisher And Registrant||European Space Agency|
|Credit Guidelines||European Space Agency, 2015-08-25T22:00:00Z, 074335, 17.56_20190403_1200. https://doi.org/10.5270/esa-8avt4we|