Observations of the flaring Fermi-LAT blazars and prospects in spectro-polarimetry with SALT-RSS

Abstract

The Fermi Gamma-Ray Space telescope has identified 1741 active galactic nuclei during its first four years of observation (2008-2012) and detected 1145 blazars and 573 blazar candidates of uncertain type (BCUs) as listed in the Third Fermi-LAT Point Source Catalog (3FGL). Since Fermi typically operates in survey mode, sources from the whole sky are monitored almost continuously. Daily or sub-daily Fermi-LAT binned light-curves of bright blazars above 100 MeV can be produced for any given time range since August 2008. It is thus possible to identify flaring periods of blazars and trigger observations with South Africa-based optical telescopes to perform gamma-ray versus optical correlation studies of flux variability. Also, the recently commissioned polarisation capability of the Robert Stobie Spectrograph (RSS) on the 10-meter class Southern African Large Telescope (SALT) at the South African Astronomical Observatory (SAAO), Sutherland, is expected to contribute to the characterisation of the wavelength dependent radiation emission mechanisms of these objects. We report our preliminary studies on the blazar 4C +01.02 and discuss the prospects for spectro-polarimetry of a broader sample of flaring blazars