Abstract Details

Name: Neeraj Kumari
Affiliation: Physical Research Laboraory India
Conference ID: ASI2021_522
Title : X-ray and UV/optical variabilties in Mrk 509
Authors and Co-Authors : Neeraj Kumari (PRL, Ahmedabad), Main Pal (Centre for Theoretical Physics, Jamia Millia Islamia, New Delhi), Sachindra Naik (PRL, Ahmedabad), Arghajit Jana (PRL, Ahmedabad), Gaurava K. Jaisawal (National Space Institute, Technical University of Denmark, Elektrovej 327-328, DK-2800 Lyngby, Denmark), Pankaj Kushwaha (ARIES, Nainital)
Abstract Type : Oral
Abstract Category : Extragalactic Astronomy
Abstract : In this work, we performed a detailed spectral and timing analysis of the Seyfert~1 galaxy Mrk~509 using data from the SWIFT observatory spanned over ~13 years. To study the variability properties from the Optical/UV to X-ray emission, we used a total of 275 observations in this work. The average spectrum over the entire duration exhibits a strong soft X-ray excess above the power-law continuum. The soft X-ray excess is well described by two thermal components. The warm thermal component is likely due to the presence of an optically thick and cool warm Comptonizing plasma in the inner accretion disc. The fractional variability amplitude is found to be decreasing with increasing wavelength i.e. from soft X-ray to UV/Optical emission. However, the hard X-ray (2-8 keV) emission shows a very low variability. The strength of the correlation between the hard X-ray and UV/optical emission is investigated and found to be lower compared to that of between the UV and Optical bands. These are confirmed by using the flux-flux positive offset method. These results clearly suggest that the emitting regions of the X-ray and UV/Optical emission are likely distinct or partly interacting. After removing slow variations, we find that the lag spectrum is well described by the 4/3 rule for the standard Shakura-Sunyaev disk when we omit X-ray lags. Observed zero lags among UV bands are possibly due to stratified regions in the disk. All these results suggest that the UV emissions are likely reprocessed in the accretion disk to give X-ray and the Optical emission.