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F. Tombesi

Publications and source records attributed to F. Tombesi.

128 records · Page 8Linked to original sources

Outflows and winds in AGNs: a case for Simbol-X

Chandra and XMM-Newton X-ray observations are accumulating evidence for massive, high velocity outflows in Seyfert galaxies and quasars, most likely originating very close to the central supermassive black hole. These results are offering new potential to probe the launching regions of relativistic jets/outflows, and to quantify their feedback impact on the host galaxy and/or cluster of galaxies. The most important signature of these phenomena is the detection of blueshifted absorption lines of highly ionized iron at energies usually greater than ~7 keV. The lack of sensitivity of present day X-ray observatories at these energies gives rise to bias against the detection of more ``extreme'' outflows, with highest velocity and ionization, which would be blueshifted at energies >10 keV. Thus, simulations with Simbol-X were carried out to test its capability of detecting absorption lines/edges between 5-20 keV, in order to probe the dynamics (i.e. measurement of velocity variations) of the absorbing gas, as well as the highest (up to relativistic speeds) velocity and ionization components. We found that the unprecedented sensitivity of Simbol-X between 5-30 keV is a great opportunity to obtain important improvements in this research field.

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Correlated modulation between the redshifted Fe K alpha line and the continuum emission in NGC 3783

It has been suggested that X-ray observations of rapidly variable Seyfert galaxies may hold the key to probe the gas orbital motions in the innermost regions of accretion discs around black holes and, thus, trace flow patterns under the effect of the hole strong gravitational field. We explore this possibility analizing XMM-Newton observations of the seyfert 1 galaxy NGC 3783. A detiled time-resolved spectral analysis is performed down to the shortest possible time-scales (few ks) using "excess maps" and cross-correlating light curves in different energy bands. In addition to a constant core of the Fe K alpha line, we detected a variable and redshifted Fe K alpha emission feature between 5.3-6.1 keV. The line exhibits a modulation on a time-scale of 27 ks that is similar to and in phase with a modulation of the 0.3-10 keV source continuum. The time-scale of the correlated variability of the redshifted Fe line and continuum agrees with the local dynamical time-scale of the accretion disc at 10 r_g around a black hole of 10^7 M_sun. Given the shape of the redshfted line emission and the overall X-ray variability pattern, the line is likely to arise from the relativistic region near the black hole.

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