| Name: | Jithesh V |
| Affiliation: | CHRIST (Deemed to be University), Bengaluru |
| Conference ID : | ASI2024_173 |
| Title : | Broadband Spectral Variability of Ultra-Luminous X-ray Source Holmberg IX X-1 |
| Authors : | V. Jithesh |
| Authors Affiliation: | Department of Physics and Electronics, CHRIST (Deemed to be University), Bengaluru 560029 |
| Mode of Presentation: | Poster |
| Abstract Category : | High Energy Phenomena, Fundamental Physics and Astronomy |
| Abstract : | We present the broadband X-ray spectral analysis of the archetype ultra-luminous X-ray source Holmberg IX X-1 observed by XMM-Newton and NuSTAR during 2018-2021. The XMM-Newton spectra in the 0.3-10 keV energy band were fitted with absorbed thermal Comptonisation models, and the source exhibited spectral shape variation as well as parameter variation, especially the photon index decreases as the flux increases. The broadband spectra in the 0.3-30 keV energy band from the simultaneous XMM-Newton and NuSTAR observations cannot provide a satisfactory fit with two-thermal Comptonisation models for all observations. We thus used two optically thick thermal components along with a non-thermal hard component to model the broadband spectra, and the model fitting suggests the broadband spectral variability between the epochs. We will discuss spectral evolution scenarios of Holmberg IX X-1 based on the different spectral components used in the analysis. |
