Evidence of Heavy Obscuration in the Low-Luminosity AGN NGC 4941

Published 26 Nov 2021 in astro-ph.HE and astro-ph.GA | (2111.13508v1)

Abstract: We present the results obtained from timing and spectral studies of the highly obscured low luminosity active galactic nucleus NGC~4941 using data obtained from the {\it Nuclear Spectroscopic Telescope Array} and the {\it Neil Gehrels Swift} Observatories. We find similar variability in $3-10$~keV and $10-60$~keV energy ranges with fractional rms variability of $\sim$14\%. We investigate broad-band spectral properties of the source in 3-150 keV range, using data from {\it NuSTAR} and {\it Swift}/BAT, with phenomenological slab model and physically motivated {\tt mytorus} model. From the spectral analysis, we find heavy obscuration with the global average column density of the obscured material as $3.09^{{+1.68}_{-1.01}} \times 10^{24}$ cm$^{-2}$. Evidence of a strong reflection component is observed in the spectrum. We detect a strong iron line with an equivalent width of $\sim$1~keV. From the slab model, we obtain the exponential cutoff energy as $177^{{+92}_{-16}$~keV.} From this, we estimate the Compton cloud properties with the hot electron temperature $kT_{\rm e} = 59^{{+31}_{-5}$~keV} and the optical depth $\tau = 2.7^{{+0.2}_{-1.6}$.}