We propose NuSTAR observations of two among the X-ray brightest (F 0.5-10 > 510^-13 ergs s^-1 cm^-2, L 2-10 > 10^45 ergs s^-1) radio-quiet QSOs at z > 1.8,complemented by a joint, short XMM-Newton exposure for one of them. Our totaltime request is 250ks with NuSTAR and 30ks with XMM-Newton. By looking atrest-frame energies up to virgul 200-300 keV, our goal is to measure unambiguouslythe presence of spectral cut-offs at rest-frame energies as high as E c=500 keV.This is not possible for targets in the local Universe, where NuSTAR is justsensitive to E c < 250 keV. Our sample is unique and will allow unprecedentedmeasurements of E c in distant AGN with such X-ray luminosities. Our programwill prove for the first time whether there is a physical limit to the temperature of AGN.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2017-12-29T06:48:16Z/2017-12-29T17:21:36Z
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, Dr Giorgio Lanzuisi, 2019, 'THE HIGH-ENERGY CUT-OFF IN HIGH-Z QSOS: A FIRST CUT', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-dc2hedv
