Long-term monitoring of the archetype Seyfert galaxy MCG-6-30-15: X-ray, optical and near-IR variability of the corona, disc and torusReportar como inadecuado




Long-term monitoring of the archetype Seyfert galaxy MCG-6-30-15: X-ray, optical and near-IR variability of the corona, disc and torus - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

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We present long-term monitoring of MCG-6-30-15 in X-rays, optical and near-IR wavelengths,collected over 5 yr of monitoring. We determine the power spectrum density of all the observedbands and show that after taking into account the host contamination similar power is observedin the optical and near-IR bands. There is evidence for a correlation between the light curvesof the X-ray photon flux and the optical B band, but it is not possible to determine a lag withcertainty, with the most likely value being around 0 d. Strong correlation is seen betweenthe optical and near-IR bands. Cross-correlation analysis shows some complex probabilitydistributions and lags that range from 10 to 20 d, with the near-IR following the opticalvariations. Filtering the light curves in frequency space shows that the strongest correlations arethose corresponding to the shortest time-scales. We discuss the nature of the X-ray variabilityand conclude that this is intrinsic and cannot be accounted for by absorption episodes due tomaterial intervening in the line of sight. It is also found that the lags agree with the relationτ ∝ λ4-3, as expected for an optically thick geometrically thin accretion disc, although for alarger disc than that predicted by the estimated black hole mass and accretion rate in MCG-6-30-15. The cross-correlation analysis suggests that the torus is located at ∼20 light-days fromthe central source and at most at ∼50 light-days from the central region. This implies an activegalactic nucleus bolometric luminosity of ∼3 × 1043 erg s−1 cm−2.Nota general

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Autor: Lira Teillery, Paulina; - Arevalo, P.; - Uttley, P.; - McHardy, I.; - Videla, L.; -

Fuente: http://repositorio.uchile.cl/



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