Abstract Details
| Name: Sanna Gulati Affiliation: Manipal Centre for Natural Sciences, MAHE Conference ID: ASI2019_372 Title : Short-term optical variability in misaligned active galaxies Authors and Co-Authors : Sanna Gulati, Debbijoy Bhattacharya, C.S. Stalin Abstract Type : Poster Abstract Category : Extragalactic Astronomy Abstract : The Large Area Telescope (LAT) on-board Fermi Gamma-ray Space Telescope has detected gamma-ray emission from ~5500 sources utilising 8 years of observations (2008-2016). Majority of the identified sources belong to the blazar class (jet inclination angle < 10 degree) of active galactic nuclei (AGN). Blazars exhibit extreme short term optical variability, known as intra-night optical variability (INOV) which is expected to have jet origin. Since gamma-rays are originated in the jet and jet emission falls off with increasing jet to line-of-sight angle, the sources with large jet inclination angles are expected to be gamma-ray weak and/or exhibit weak/no signature of INOV. However, Fermi has detected gamma-ray emission from 24 misaligned active galaxies (MAGN: angle >~ 10 degree) which indicates a presence of strong jet in these sources. Therefore, in the scenario of jet origin of INOV, one would expect these gamma-ray bright MAGN to exhibit strong INOV. However, till date no study on the INOV nature of these gamma-ray bright MAGN has been reported. In this work, short-term optical variability of gamma-ray bright MAGN is studied using observations from 1.3 m JCB Telescope (Kavalur) and Himalayan Chandra Telescope (Hanle). Scaled C-test and power enhanced F-test were used to quantify the variability of the 8 sources observed till date over multiple epochs. Strong presence of INOV with high duty cycle in few of the gamma-ray detected MAGN is detected. The results of this ongoing observation program will be presented here. |