Examinando por Autor "Parker, M. L."

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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
Detection of a possible multiphase ultra-fast outflow in IRAS 13349+2438 with NuSTAR and XMM-Newton.
(Oxford Academics: Blackwell Publishing, 2020-08-25) Parker, M. L.; Matzeu, G. A.; Alston, W. N.; Fabian, A. C.; Lobban, A.; Miniutti, G.; Pinto, C.; Santos Lleó, M.; Schartel, N.; European Space Agency (ESA); 0000-0002-5635-5340; 0000-0003-1994-5322; 0000-0003-2658-6559; 0000-0001-5948-8360; 0000-0003-2532-7379; 0000-0002-9378-4072; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
We present joint NuSTAR and XMM–Newton observations of the bright, variable quasar IRAS 13349+2438. This combined data set shows two clear iron absorption lines at 8 and 9 keV, which are most likely associated with two layers of mildly relativistic blueshifted absorption, with velocities of ∼0.14c and ∼0.27c. We also find strong evidence for a series of Ly α absorption lines at intermediate energies in a stacked XMM–Newton EPIC-pn spectrum, at the same blueshift as the lower velocity iron feature. This is consistent with a scenario where an outflowing wind is radially stratified, so faster, higher ionization material is observed closer to the black hole, and cooler, slower material is seen from streamlines at larger radii.
Acceso Abierto
The first broad-band X-ray view of the narrow-line Seyfert 1 Ton S180
(Oxford Academics: Oxford University Press, 2020-07-15) Matzeu, G. A.; Nardini, E.; Parker, M. L.; Reeves, J. N.; Braito, V.; Porquet, D.; Middei, R.; Kammoun, E.; Lusso, E.; Alston, W. N.; Giustini, M.; Lobban, A. P.; Joyce, A. M.; Igo, Z.; Ebrero, J.; Ballo, L.; Santos Lleó, M.; Schartel, N.; European Research Council (ERC); European Commission (EC); Agenzia Spaziale Italiana (ASI); Istituto Nazionale di Astrofisica (INAF); Comunidad de Madrid; National Aeronautics and Space Administration (NASA); Giustini, M. [0000-0002-1329-658X]; Kammoun, E. [0000-0002-0273-218X]; Braito, V. [0000-0002-2629-4989]; Matzeu, G. [0000-0003-1994-5322]; Parker, M. [0000-0002-8466-7317]; Lobban, A. [0000-0002-6433-1357]; Santos Lleo, M. [0000-0001-5948-8360]; Middei, R. [0000-0001-9815-9092]; Igo, Z. [0000-0001-9274-1145]; Alston, W. [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
We present joint XMM-Newton and NuSTAR observations of the 'bare' narrow-line Seyfert 1 Ton S180 (z = 0.062), carried out in 2016 and providing the first hardX-ray view of this luminous galaxy. We find that the 0.4-30 keV band cannot be self-consistently reproduced by relativistic reflection models, which fail to account simultaneously for the soft and hard X-ray emission. The smooth soft excess prefers extreme blurring parameters, confirmed by the nearly featureless nature of the Reflection Grating Spectrometer (RGS) spectrum, while the moderately broad Fe K line and the modest hard excess above 10 keV appear to arise in a milder gravity regime. By allowing a different origin of the soft excess, the broad-band X-ray spectrum and overall spectral energy distribution (SED) are well explained by a combination of (a) direct thermal emission from the accretion disc, dominating from the optical to the far/extreme UV; (b) Comptonization of seed disc photons by a warm (kT(e) similar to 0.3 keV) and optically thick (tau similar to 10) corona, mostly contributing to the soft X-rays; (c) Comptonization by a standard hot (kT(e) greater than or similar to 100 keV) and optically thin (tau < 0.5) corona, responsible for the primary X-ray continuum; and (d) reflection from the mid/outer part of the disc. The two coronae are suggested to be rather compact, with R-hot less than or similar to R-warm less than or similar to 10 r(g). Our SED analysis implies that Ton S180 accretes at super-Eddington rates. This is a key condition for the launch of a wind, marginal (i.e. 3.1 sigma significance) evidence of which is indeed found in the RGS spectrum.