The lively accretion disk in NGC 2992. II. The 2019/2021 X-ray monitoring campaigns

Abstract

We report on the short and long term X-ray properties of the bright nearby Seyfert 2 galaxy NGC 2992, which was extensively observed with Swift, XMM-Newton and NuSTAR. Swift targeted the source more than 100 times between 2019 and 2021 in the context of two monitoring campaigns. Both time-averaged and time-resolved analyses are performed, and we find that the short-to-long term spectral properties of NGC 2992 are dominated by a highly variable nuclear continuum. The source varied in the 2-10 keV energy band from 0.6 to 12 $\times$ 10${}^{-11}$ erg cm${}^{-2}$ s${}^{-1}$ during the two year long Swift monitoring. The fastest 2-10 keV flux change (by a factor of $\sim 60\%$) occurred on a timescale of a few hours. The overall emission spectrum of the source is consistent with a power law-like continuum ($\hat{I}“=1.69\pm 0.01$) absorbed by a constant line-of-sight column density N${}_H=(7.8\pm 0.1)\times$ 10${}^{21}$ $\mathrm{c}{\mathrm{m}}^{-2}$. The reflected emission is likely due to matter with an average column density N${}_{\mathrm{H}}=(9.6\pm 2.7)\times$ 10${}^{22}$ $\mathrm{c}{\mathrm{m}}^{-2}$, thus NGC 2992 appears to have a globally Compton-thin circumnuclear medium. This scenario is fully supported by an independent analysis of the fractional variability and by XMM-Newton multi-year spectra.

21 pages, 17 figures. Accepted for publication in MNRAS