2023MNRAS.519.6267T -
Mon. Not. R. Astron. Soc., 519, 6267-6283 (2023/March-2)
Systematic broad-band X-ray study of super-Eddington accretion on to supermassive black holes - I. X-ray continuum.
TORTOSA A., RICCI C., HO L.C., TOMBESI F., DU P., INAYOSHI K., WANG J.-M., SHANGGUAN J. and LI R.
Abstract (from CDS):
We present the first systematic broad-band X-ray study of super-Eddington accretion onto supermassive black holes with simultaneous NuSTAR and XMM-Newton or Swift/XRT observations of a sample of eight super-Eddington accreting Active Galactic Nuclei (AGNs) with Eddington ratio 1 < λ Edd < 426. We find that the super-Eddington accreting massive black holes (SEAMBHs) show a steep primary continuum slope as expected for sources accreting in the super-Eddington regime, mostly dominated by relativistic reflection. The iron K α emission lines of the sources of our sample show relativistic broadening. In addition, the equivalent widths of the narrow components of the iron K α lines follow the 'X-ray Baldwin' effect, also known as the 'Iwasawa-Taniguchi' effect. We found a statistically significant correlation between the photon index of the primary power law and the Eddington ratio, consistent with past studies. Moreover, as expected for super-Eddington sources, the median value of the reflection fraction of the sources we analysed is a factor ∼ 2 higher than the median reflection fraction value of the type 1 AGN from the BASS sample. We are able to estimate the coronal temperature for three sources of our sample: Mrk 382 (kTe = 7.75 keV), PG 0026+129 (kTe = 39 keV), and IRAS 04416+1215 (kTe = 2.95 keV). Looking at the position of the SEAMBHs sources of our sample in the compactness-temperature diagram it appears that in super-Eddington AGN, as for lower Eddington ratio AGN, the X-ray corona is controlled by pair production and annihilation.
Abstract Copyright:
© 2022 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society
Journal keyword(s):
accretion, accretion discs - black hole physics - galaxies: active - galaxies: nuclei - galaxies: Seyfert - X-rays: galaxies
Simbad objects:
10
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