%0 Generic %1 page2013xrays %A Page, M. J. %A Simpson, C. %A Mortlock, D. J. %A Warren, S. J. %A Hewett, P. C. %A Venemans, B. P. %A McMahon, R. G. %D 2013 %K high-z quasar xrays %T X-rays from the redshift 7.1 quasar ULAS J1120+0641 %U http://arxiv.org/abs/1311.1686 %X We present X-ray imaging and spectroscopy of the redshift z=7.084 quasar ULAS J112001.48+064124.3 obtained with Chandra and XMM-Newton. The quasar is detected as a point source with both observatories. The Chandra observation provides a precise position, confirming the association of the X-ray source and the quasar, while sufficient photons are detected in the XMM-Newton observation to yield a meaningful X-ray spectrum. In the XMM-Newton observation the quasar has a 2-10 keV luminosity of 4.7 +- 0.9 times 10^44 ergs/s and a spectral slope alpha = 1.6 +0.4 -0.3 (where f_nu propto nu^-alpha). The very soft spectrum suggests that the quasar is accreting above the Eddington rate, which would help to reduce the discrepancy between the age of the quasar implied by the small size of the ionized near zone in which it sits (<10^7 years), and the characteristic e-folding time (2.5 times 10^7 years if L/L_Edd=2). Such super-Eddington accretion would also alleviate the challenging constraints on the seed black hole mass, and the remnant of an individual population III star is a plausible progenitor if an average L/L_Edd>1.46 has been maintained over the quasar's lifetime.

@misc{page2013xrays, abstract = {We present X-ray imaging and spectroscopy of the redshift z=7.084 quasar ULAS J112001.48+064124.3 obtained with Chandra and XMM-Newton. The quasar is detected as a point source with both observatories. The Chandra observation provides a precise position, confirming the association of the X-ray source and the quasar, while sufficient photons are detected in the XMM-Newton observation to yield a meaningful X-ray spectrum. In the XMM-Newton observation the quasar has a 2-10 keV luminosity of 4.7 +- 0.9 times 10^44 ergs/s and a spectral slope alpha = 1.6 +0.4 -0.3 (where f_nu propto nu^-alpha). The very soft spectrum suggests that the quasar is accreting above the Eddington rate, which would help to reduce the discrepancy between the age of the quasar implied by the small size of the ionized near zone in which it sits (<10^7 years), and the characteristic e-folding time (2.5 times 10^7 years if L/L_Edd=2). Such super-Eddington accretion would also alleviate the challenging constraints on the seed black hole mass, and the remnant of an individual population III star is a plausible progenitor if an average L/L_Edd>1.46 has been maintained over the quasar's lifetime.}, added-at = {2013-11-08T16:17:32.000+0100}, author = {Page, M. J. and Simpson, C. and Mortlock, D. J. and Warren, S. J. and Hewett, P. C. and Venemans, B. P. and McMahon, R. G.}, biburl = {https://www.bibsonomy.org/bibtex/2f2433380a8cd162f59c14fb3af175b3f/miki}, description = {[1311.1686] X-rays from the redshift 7.1 quasar ULAS J1120+0641}, interhash = {7d68695dabdb278173f5b92543a04012}, intrahash = {f2433380a8cd162f59c14fb3af175b3f}, keywords = {high-z quasar xrays}, note = {cite arxiv:1311.1686Comment: Submitted to MNRAS Letters}, timestamp = {2013-11-08T16:17:32.000+0100}, title = {X-rays from the redshift 7.1 quasar ULAS J1120+0641}, url = {http://arxiv.org/abs/1311.1686}, year = 2013 }