Examinando por Autor "Uttley, P."

Mostrando 1 - 2 de 2

Restringido
A dynamic black hole corona in an active galaxy through X-ray reverberation mapping
(Springer Nature Research Journals, 2020-01-20) Alston, W. N.; Fabian, A. C.; Kara, E.; Parker, M. L.; Dovciak, M.; Pinto, C.; Jiang, J.; Middleton, M. J.; Miniutti, G.; Walton, D. J.; Wilkins, D. R.; Buisson, D. J.; Caballero García, M. D.; Cackett, E. M.; De Marco, B.; Gallo, L. C.; Lohfink, A. M.; Reynolds, C. S.; Uttley, P.; Young, A. J.; Zogbhi, A.; European Research Council (ERC); Science and Technology Facilities Council (STFC); European Space Agency (ESA); European Commission (EC); Agencia Estatal de Investigación (AEI); 0000-0003-2658-6559; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
X-ray reverberation echoes are assumed to be produced in the strongly distorted spacetime around accreting supermassive black holes. This signal allows us to spatially map the geometry of the inner accretion flow1,2—a region that cannot yet be spatially resolved by any telescope—and provides a direct measure of the black hole mass and spin. The reverberation timescale is set by the light travel path between the direct emission from a hot X-ray corona and the reprocessed emission from the inner edge of the accretion disk3,4,5,6. However, there is an inherent degeneracy in the reverberation signal between black hole mass, inner disk radius and height of the illuminating corona above the disk. Here we use a long X-ray observation of the highly variable active galaxy IRAS 13224−3809 to track the reverberation signal as the system evolves on timescales of a day7,8. With the inclusion of all the relativistic effects, modelling reveals that the height of the X-ray corona increases with increasing luminosity, providing a dynamic view of the inner accretion region. This simultaneous modelling allows us to break the inherent degeneracies and obtain an independent timing-based estimate for the mass and spin of the black hole. The uncertainty on black hole mass is comparable to the leading optical reverberation method9, making X-ray reverberation a powerful technique, particularly for sources with low optical variability10.
Restringido
Accretion in strong field gravity with eXTP
(Springer Link, 2018-12-07) De Rosa, A.; Uttley, P.; Gou, L.; Liu, Y.; Bambi, C.; Barret, Didier; Belloni, T.; Berti, E.; Bianchi, S.; Caiazzo, I.; Casella, P.; Cui, W. K.; D´Ammando, F.; Dauser, T.; Del Santo, M.; De Marco, B.; Di Salvo, T.; Done, C.; Dovciak, M.; Fabian, A. C.; Falanga, M.; Gambino, A. F.; Gendre, B.; Grinberg, V.; Heger, A.; Homan, J.; Iaria, R.; Jiang, J.; Jin, C. C.; Koerding, E.; Linares, M.; Liu, Z.; Maccarone, Thomas J.; Malzac, J.; Manousakis, A.; Marin, F.; Marinucci, A.; Mehdipour, M.; Méndez, M.; Migliari, S.; Miller, C.; Miniutti, G.; Nardini, E.; O´Brien, P. T.; Osborne, Julian P.; Petrucci, P. O.; Possenti, A.; Riggio, A.; Rodríguez, J.; Sanna, A.; Shao, L. J.; Sobolewska, M.; Sramkova, E.; Stevens, A. L.; Stiele, H.; Stratta, G.; Stuchlik, Z.; Svoboda, J.; Tamburini, F.; Tauris, T. M.; Tombesi, F.; Torok, G.; Urbanec, M.; Vicent, F.; Wu, Q. W.; Yuan, F.; Zand, J. J. M.; Zdziarski, A. A.; Zhou, X.; Feroci, M.; Ferrari, V.; Gualtieri, L.; Heyl, J.; Ingram, A.; Karas, V.; Lu, F. J.; Luo, B.; Matt, G.; Motta, S. E.; Neilsen, J.; Pani, P.; Santangelo, A.; Shu, X. W.; Wang, J. F.; Wang, J. M.; Xue, Y. Q.; Xu, Y. P.; Yuan, W. M.; Yuan, Y. F.; Zhang, S. N.; Zhang, S.; Agudo, I.; Amati, L.; Andersson, N. A.; Baglio, C.; Bakala, P.; Baykal, A.; Bhattacharyya, S.; Bombaci, I.; Bucciantini, N.; Capitanio, F.; Ciolfi, R.; Istituto Nazionale di Astrofisica (INAF); Chinese Academy of Sciences (CAS); National Science Centre, Poland (NCN)
In this paper we describe the potential of the enhanced X-ray Timing and Polarimetry (eXTP) mission for studies related to accretion flows in the strong field gravity regime around both stellar-mass and supermassive black-holes. eXTP has the unique capability of using advanced “spectral-timing-polarimetry” techniques to analyze the rapid variations with three orthogonal diagnostics of the flow and its geometry, yielding unprecedented insight into the inner accreting regions, the effects of strong field gravity on the material within them and the powerful outflows which are driven by the accretion process. X-spinmeasurements