| Name: | Athira Nandakumar |
| Affiliation: | Indian Institute of Astrophysics |
| Conference ID: | ASI2025_199 |
| Title: | Powering Mechanism of the Ultraluminous X-ray Source NGC 4395 X-1 |
| Authors: | Athira Nandakumar, Dr. Santanu Mondal, Dr. Jithesh V |
| Authors Affiliation: | Indian Institute of Astrophysics
CHRIST(Deemed to be) University |
| Mode of Presentation: | Poster |
| Abstract Category: | High Energy Phenomena, Fundamental Physics and Astronomy |
| Abstract: | Ultra-luminous X-ray sources (ULXs) are off-nuclear sources having unusual luminosity in X-
rays, nearly or higher than the Eddington limit. Though they have been studied extensively
using data from different observatories, their powering mechanism is still a topic of debate. It
is believed that stellar mass black holes (BHs) accreting in the super-Eddington limit,
intermediate mass BHs accreting in the sub-Eddington regime or accreting in the super-
Eddington regime with lower accretion efficiency can power such systems. In this work, we
studied X-ray spectral variability of the ULX NGC 4395 X-1 using two decades of XMM-
Newton observations from 2002 to 2022. It is one of the nearest ULXs detected outside our
Galaxy at a distance of ~5 Mpc. The X-ray luminosity of this source is (1-3)x10^39 erg/s. This
source also exhibited variability and X-ray flaring activities over time. All available spectra of
the source are fitted using both phenomenological and physical models. Investigating these variability properties of NGC 4395 X-1 provided us with valuable insights into the dynamics of accretion and the central compact object. In this poster presentation, I will discuss the progress of the work in understanding the powering mechanism and the intrinsic properties of the central black hole from different model fitted parameters. |
