Browsing by Author "Tortosa, Alessia"

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    BASS-XL: X-ray variability properties of unobscured active galactic nuclei
    (2023) Tortosa, Alessia; Ricci, Claudio; Arevalo, Patricia; Koss, Michael J.; Bauer, Franz E.; Trakhtenbrot, Benny; Mushotzky, Richard; Temple, Matthew J.; Ricci, Federica; Lilayu, Alejandra Rojas; Kawamuro, Taiki; Caglar, Turgay; Liu, Tingting; Harrison, Fiona; Oh, Kyuseok; Powell, Meredith Clark; Stern, Daniel; Urry, Claudia Megan
    We investigate the X-ray variability properties of Seyfert 1 Galaxies belonging to the BAT AGN Spectroscopic Survey (BASS). The sample includes 151 unobscured (N-H < 10(22) cm(-2)) AGNs observed with XMM-Newton for a total exposure time of similar to 27 ms, representing the deepest variability study done so far with high signal-to-noise XMM-Newton observations, almost doubling the number of observations analysed in previous works. We constrain the relation between the normalized excess variance and the 2-10 keV AGN luminosities, black hole masses, and Eddington ratios. We find a highly significant correlation between sigma(2)(NXS) and M-BH, with a scatter of similar to 0.85 dex. For sources with high L2-10 this correlation has a lower normalization, confirming that more luminous (higher mass) AGNs show less variability. We explored the sigma(2)(NXS) versus M-BH relation for the sub-sample of sources with M-BH estimated via the 'reverberation mapping' technique, finding a tighter anticorrelation, with a scatter of similar to 0.65 dex. We examine how the sigma(2)(NXS) changes with energy by studying the relation between the variability in the hard (3-10 keV) and the soft (0.2-1 keV)/medium (1-3 keV) energy bands, finding that the spectral components dominating the hard energy band are more variable than the spectral components dominating in softer energy bands, on time-scales shorter than 10 ks.
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    Localizing narrow Fe Kα emission within bright AGN
    (2022) Andonie, Carolina; Bauer, Franz E.; Carraro, Rosamaria; Arevalo, Patricia; Alexander, David M.; Brandt, William N.; Buchner, Johannes; He, Adam; Koss, Michael J.; Ricci, Claudio; Salinas, Vicente; Solimano, Manuel; Tortosa, Alessia; Treister, Ezequiel
    Context. The 6.4 keV Fe K alpha emission line is a ubiquitous feature in X-ray spectra of active galactic nuclei (AGN), and its properties track the interaction between the variable primary X-ray continuum and the surrounding structure from which it arises.