A Weakening Compton Hump and Soft X-Ray Excess Detected in the Seyfert 1 Galaxy MCG –02–58–22

Abstract

We have carried out an extensive X-ray spectral study of the bare Seyfert-1 galaxy MCG -02-58-22 to ascertain the nature of the X-ray reprocessing media, using observations from Suzaku (2009) and simultaneous observations from XMM-Newton and NuSTAR (2016) . The most significant results of our investigation are: 1. The primary X-ray emission from the corona is constant in these observations, both in terms of the power law slope (Γ = 1.80) and luminosity (L 2−10 keV = 2.55 × 10 44 erg s −1 ). 2. The soft excess flux decreased by a factor of two in 2016, the Compton hump weakened/vanished in 2016, and the narrow FeKα emission line became marginally broad (σ = 0.35 ± 0.08 keV) and its flux doubled in 2016. 3. From physical model fits we find that the normalization of the narrow component of the FeKα line does not change in the two epochs, although the Compton hump vanishes in the same time span. Since the primary X-ray continuum does not change, we presume that any changes in the reprocessed emission must arise due to changes in the reprocessing media. Our primary conclusions are: A. The vanishing of the Compton hump in 2016 can probably be explained by a dynamic clumpy torus which is infalling/outflowing, or by a polar torus wind. B. The torus in this AGN possibly has two structures: an equatorial toroidal disk (producing the narrow FeKα emission) and a polar component (producing the variable Compton hump), C. The reduction of the soft-excess flux by half and increase in the FeKα flux by a factor of two in the same period cannot be adequately explained by ionized disk reflection model alone.

A Radio, Optical, UV, and X-Ray View of the Enigmatic Changing-look Active Galactic Nucleus 1ES 1927+654 from Its Pre- to Postflare States

“…Popular theories suggest that it could arise out of thermal Comptonization of the UV seed photons by a warm corona (Done et al 2012) or it can also arise out of the reflection of hard X-ray photons from the corona off the accretion disk (García et al 2014). Even after a considerable number of studies on the subject (Laha et al 2011(Laha et al , 2013(Laha et al , 2014aEhler et al 2018;García et al 2019;Laha et al 2019;Tripathi et al 2019;Waddell et al 2019;Ghosh & Laha 2020;Laha et al 2020;Ursini et al 2020;Laha & Ghosh 2021), there has not been a consensus on the physics of the origin of the soft X-ray excess. X-ray reverberation lead/lag studies too have yielded conflicting results for different sources (Kara et al 2016).…”

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

“…This may be either due to the non-simultaneity of the spectra or due to inter-calibration issues among the detectors as also reported for other observations (e.g. Porquet et al 2018;Laha & Ghosh 2021).…”

A radio, optical, UV and X-ray view of the enigmatic changing look Active Galactic Nucleus 1ES~1927+654 from its pre- to post-flare states

“…Popular theories suggest that it could arise out of thermal Comptonization of the UV seed photons by a warm corona (Done et al 2012) or it can also arise out of the reflection of the hard X-ray photons from the corona off the accretion disk (García et al 2014). Even after considerable studies on the subject (Laha et al 2011(Laha et al , 2013(Laha et al , 2014aEhler et al 2018;Laha et al 2020;García et al 2019;Waddell et al 2019;Laha et al 2019;Tripathi et al 2019;Ghosh & Laha 2020;Ursini et al 2020;Laha & Ghosh 2021) there has not been a consensus on the physics of the origin of the soft X-ray excess. Xray reverberation lead/lag studies too have yielded conflicting results for different sources (Kara et al 2016).…”