A dataset provided by the European Space Agency

Name 014874
Title X-ray weak broad-line quasars: absorption or intrinsic X-ray weakness


DOI https://doi.org/10.5270/esa-zrbak7m
Author Mr Guido Risaliti
Description We propose to observe a sample of 20 soft X-ray weak, optically red quasars,
discovered by the Hamburg Quasar Survey. The lack of detection in the ROSAT
PSPC, despite their relatively bright optical emission make them a peculiar
class of quasars, classified as type 1 in the optical but type 2 in the X-rays.
Establishing the X-ray properties of these objects is important for (1) the
X-ray background synthesis models (they could be the missing QSO2s), (2) the
unified models (they challenge the traditional torus model) and (3) the long
debated problem on the discrepancy between optical and X-ray luminosity
functions. XMM provides the unique opportunity to observe a well defined sample
of such sources and measure their absorption column density in many cases.
Publication No observations found associated with the current proposal
Instrument EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage 2002-11-12T07:49:30Z/2003-12-19T00:32:29Z
Version 17.56_20190403_1200
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.
Creator Contact https://www.cosmos.esa.int/web/xmm-newton/xmm-newton-helpdesk
Date Published 2005-01-20T00:00:00Z
Publisher And Registrant European Space Agency
Credit Guidelines European Space Agency, Mr Guido Risaliti, 2005, 014874, 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-zrbak7m