English

Variable mass accretion and failed wind explain changing look phenomena in NGC 1365

High Energy Astrophysical Phenomena 2022-06-22 v1

Abstract

Changing look active galactic nuclei (CLAGNs) show complex nature in their X-ray spectral shape and line of sight column density variation. The physical mechanisms responsible for these variations are unclear. Here, we study the spectral properties of a CLAGN, NGC\,1365 using combined {\it XMM-Newton} and {\it NuSTAR} observations to understand the CL behavior. The model fitted mass accretion rate varied between 0.003±0.0010.003\pm 0.001 and 0.009±0.0020.009\pm0.002 M˙Edd\dot M_{\rm Edd} and the dynamic corona changed from 28±328\pm 3 to 10±110\pm1 rgr_g. We found that the variable absorption column density correlates with the mass accretion rate and the geometry of the corona. The derived wind velocity was sufficiently low compared to the escape velocity to drive the wind away from the disc for the epochs when column densities were high. This suggests that the high and variable absorption can be due to failed winds from the disc. Our estimated ratio of mass outflow to inflow rate from the inner region of the disc lies between 0.019±0.0060.019\pm0.006 and 0.12±0.040.12\pm0.04. From spectral fitting of the combined data, we found the mass of the central black hole to be constant 4.38±0.344.51±0.29×106M4.38\pm0.34 - 4.51\pm0.29 \times10^{6} M_\odot, consistent with earlier findings. The confidence contours of NHN_H with other model parameters show that the model fitted parameters are robust and non-degenerate. Our study construed that the changing accretion rate, which is a fundamental physical quantity and the geometry of the corona driving the CL phenomena in NGC\,1365. The physical picture considered in this work connects both variable continuum and variable absorbing medium scenarios.

Keywords

Cite

@article{arxiv.2204.02133,
  title  = {Variable mass accretion and failed wind explain changing look phenomena in NGC 1365},
  author = {Santanu Mondal and Tek P. Adhikari and Krzysztof Hryniewicz and C. S. Stalin and Ashwani Pandey},
  journal= {arXiv preprint arXiv:2204.02133},
  year   = {2022}
}

Comments

8 pages, 7 figures, 1 table, accepted for publication in A&A, comments welcome

R2 v1 2026-06-24T10:38:20.276Z