Speaker
Description
NGC 5273, a Seyfert 1.5 active galactic nucleus at $\sim$16.5 Mpc hosting a black hole of mass $M_{\rm BH} \sim (4.7 \pm 1.6) \times 10^6 \, M_{\odot}$ Bentz et al. (2014), is a well-established changing-look AGN that has undergone multiple optical spectral transitions between Type~1 and Type~1.9 states over the past two decades Neustadt et al. (2023). We present an X-ray spectral analysis of the AGN using archival NuSTAR (3--79 keV) observations from July 2014 and July 2022, supplemented by Swift/XRT (0.3--10 keV) monitoring across 2022. We characterize the variation in the photon index $\Gamma$, the Fe~K emission complex, and the broadband continuum shape using phenomenological spectral models. Our results suggest spectral hardening between the two NuSTAR epochs, with $\Gamma$ decreasing from $\sim$1.50 to $\sim$1.42, providing context for the coronal state changes probed at hard X-rays.
| Nature of work | Theoretical |
|---|