Abstract Details
| 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 and Co-Authors : Athira Nandakumar, Dr. Santanu Mondal, Dr. Jithesh V Abstract Type : 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. |