Monitoring of AGNs for variability from MIRO

Abstract

As a long term programme, a sample of blazars is being monitored from Mt Abu Infrared Observatory (MIRO). Blazars are the radio-loud AGNs with polarized, highly luminous and rapidly variable non-thermal continuum emission ranging from radio to gamma rays, from a relativistic jet. The emission shows variability at several time scales. Radio through gamma-ray spectral energy distribution (SED) of blazars exhibits two broad humps- first at UV/optical, considered to be due to synchrotron emission from the relativistic electrons, and second one in the region extending from X-ray to gamma-rays whose origin is less understood. Long term multi-wavelength monitoring of the blazars for variability is the key to obtain information on the geometry of the jets and the physical processes responsible for the high energy emissions. Here we report monitoring of several blazars using 1.2 m IR telescope and discuss recent results on some of them. In particular, PKS0716+714 and 3C66A have shown intense activity and continued in bright phase during 2003-04, drawing worldwide attention for a co-ordinated monitoring campaign.