Abstract Details
| Name: Debbijoy Bhattacharya Affiliation: Manipal Centre for Natural Sciences, MAHE Conference ID: ASI2019_380 Title : Unusual long term low activity state and long term variability of Blazars Authors and Co-Authors : Debbijoy Bhattacharya Abstract Type : Poster Abstract Category : Extragalactic Astronomy Abstract : Blazars, a subclass of active galactic nuclei (AGN), exhibit large ɣ-ray luminosities which sometimes extends to TeV energies. Blazars show variability in ɣ-rays over different time-scales ranging from flares as short as ~1 hr to flares extending for days or months. Blazars are also variables on still longer time-scales of years or decades. While there have been several studies regarding the rapid variability and flaring activity of blazars and their possible connection to varying jet parameters, reports on their long-term ɣ-ray variability are limited. A detailed study of long term variability of EGRET blazars using EGRET and Fermi observations has been carried out and a long term low activity state in ɣ-ray is noticed in few blazars. In addition, an unusual long term flaring activity in ɣ-rays along with short term flares is noticed in blazar 4C +21.35. Similar trend of long term flare was also observed in optical band. This source was also observed on April 25, 2018 by ASTROSAT. Here, the long term variability of blazars will be presented. |