Examinando por Autor "Matzeu, G. A."

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Acceso Abierto
A broadband X-ray view of the NLSy1 1E 0754.6+3928
(EDP Sciences, 2020-02-28) Middei, R.; Tombesi, F.; Vagnetti, F.; Serafinelli, R.; Bianchi, S.; Miniutti, G.; Marinucci, A.; Matzeu, G. A.; Petrucci, P. O.; Ursini, F.; Zaino, A.; Agenzia Spaziale Italiana (ASI); Istituto Nazionale Astrofisica (INAF); European Space Agency (ESA); 0000-0001-9815-9092; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. The soft X-ray band of many active galactic nuclei (AGNs) is affected by obscuration due to partially ionised matter crossing our line of sight. In this context, two past XMM-Newton observations that were six months apart and a simultaneous NuSTAR-Swift exposure of the Narrow Line Seyfert 1 galaxy 1E 0754.6+3928, which was approximately eight years later, revealed an intense and variable warm absorber (WA) and hints of additional absorbers in the Fe K alpha band.Aims. We aim to provide the first X-ray characterisation of this AGN by discussing its broadband (0.3-79 keV) spectrum and temporal properties.Methods. We conduct a temporal and spectroscopic analysis on two similar to 10 ks (net exposure) XMM-Newton snapshots performed in April and October 2006. We also study the high energy behaviour of 1E 0754.6+3928 and model its broadband spectrum by using simultaneous Swift-NuSTAR data. Both phenomenological and physically motivated models are tested.Results. We find the presence of flux variability of similar to 150% and 30% for 0.3-2 and 2-10 keV bands, respectively, and spectral changes at months timescales of Delta Gamma similar to 0.4. A reflection component that is consistent with being constant over years and arising from relatively cold material that is far from the central super massive black hole is detected. The main spectral feature shaping the 1E 0754.6+3928 spectrum is a WA. Such a component is persistent over the years and the variability of its ionisation and column density is observed down on months in the ranges 3x10(22)cm(-2)less than or similar to N-H less than or similar to 7.2x10(22)cm(-2) and 1.5 less than or similar to log (xi/erg s(-1) cm) less than or similar to 2.1. Despite the short exposures, we find possible evidence of two additional high-ionisation and high-velocity outflow components in absorption.Conclusions. Our analysis suggests the existence of a complex system of absorbers in 1E 0754.6+3928. Longer exposures are required in order to characterise, on more solid grounds, the absorbers in this AGN.
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.