| Name: Aman Upadhyay |
| Affiliation: RAMAN RESEARCH INSTITUTE |
| Conference ID: ASI2026_628 |
| Title: Understanding the accretion geometry of the M 51 ULX-8 |
| Abstract Type: Poster |
| Abstract Category: High Energy Phenomena, Fundamental Physics and Astronomy |
| Author(s) and Co-Author(s) with Affiliation: Aman Upadhyay(Raman Research Institute), Dr. Tanuman Ghosh(IUCAA), Prof. Vikram Rana(Raman Research Institute), Dr. Kinjal roy(Raman Research Institute), Dr. Rahul sharma(IUCAA), Prof. Biswajit paul(Raman Research Institute) |
| Abstract: Ultraluminous X-ray sources (ULXs) provide a valuable laboratory for studying accretion under super-Eddington conditions. We present a combined timing and spectral analysis of M51 ULX-8 aimed at constraining its accretion geometry. Using multiple independent timing analysis techniques, we detect significant quasi-periodic oscillations (QPOs) at characteristic timescales of 20,894 s, 29,713 s, and 47,893 s, indicating variability in the accretion flow over a wide range of temporal scales. These long-timescale QPOs may be associated with geometric effects such as accretion disk precession expected in super-Eddington systems. We investigate the spectral evolution of the source across different luminosity states and find that the disk emission follows a luminosity–temperature relation consistent with 𝐿∝T2, supporting a slim disk accretion geometry in the system. The combined timing and spectral properties suggest a geometrically thick, radiatively inefficient accretion flow in M51 ULX-8, where variability is closely linked to changes in the accretion structure. These results provide new constraints on the accretion geometry of M51 ULX-8 and underscore the importance of joint timing–spectral analyses in understanding the physical mechanisms driving ULXs. |
