National conference on REcent Trends in the study of Compact Objects (RETCO-V): Theory and Observation

Multiwavelength study of obscured AGN NGC 1365 using AstroSat X-ray/UVIT observations

Apr 4, 2023, 12:25 PM

15m

Auditorium (Kodaikanal Solar Observatory)

AGNs and Blazars AGNs & Blazars

Speaker

Subhashree Swain (IIA Bengaluru)

Description

We present a multi-wavelength study of the active nucleus and the off-nuclear X-ray sources in the nearby spiral galaxy, NGC 1365 using three simultaneous UV/X-ray observations by AstroSat over a two months period and archival IR observations performed with Spitzer and Herschel. Utilising the data from the Soft X-ray Telescope (SXT) on-board AstroSat, we find spectral variability mainly caused by the variation in the X-ray column density, (N${}_H$ ∼ 10${}^{22}$ - 10${}^{23}$ cm${}^{-2}$). With the accurate spatial resolution of the UVIT onboard AstroSat, We detect no significant variation in the NUV emission over the observation period. The AGN in FUV band is undetectable due to heavy intrinsic extinction. Further, the multi-wavelength IR/UV/X-ray AGN SED reveals that the AGN is in a low uminosity phase with accretion rate ∼ 0.01 L${}_{Edd}$. The steady UV emission and strong X-ray absorption variability suggest that the obscuring clouds are likely compact and affect the compact X-ray source only and do not possibly cover the extended UV emitting region. In addition, the UVIT is able to resolve two bright spots at a radius of 7" (∼ 6.3 Kpc) from the central nucleus in the South-West (SW) direction and also detect UV counterparts for one well- known ULX source.