Abstract Details
| Name: Ashwani Pandey Affiliation: Aryabhatta Research Institute of Observational Sciences ( ARIES) Conference ID: ASI2016_685 Title : Optical Quasi-Periodic Oscillations in the blazar PKS 2155-304 Authors and Co-Authors : Ashwani Pandey Affiliation : Aryabhatta Research Institute of Observational Sciences Manora Peak, Nainital, 263002, India Abstract Type : Poster Abstract Category : Extragalactic astronomy Abstract : The optical (R-band) light curve (~12 yrs) of the blazar PKS 2155-304 has been constructed by combining the publicly available SMARTS data and the ROTSE data. The light curve is, then, searched for any possible periodicities by using the structure function (SF) and discrete correlation function (DCF) techniques. We find eight possible periods which indicate two possibilities : a quasi-periodic oscillation (QPO) with an average period of ~311 days (~0.85 yr) and multiple periods of ~ 230 days (~0.63 yr) and ~550 days (~1.5 yr) with their harmonics and three independent periods of ~1270 days, ~1970 days and ~ 2490 days. No direct model explaining these year-like periodicities is available till date, however year-like periodicities are often found in many blazars. We discuss various possible physical processes responsible for year-like QPOs as well as models explaining multiple periods. |