Exceptional NIR flare in gamma-ray loud FSRQ PKS B1424-418

Abstract

The gamma-ray loud flat spectrum radio quasar PKS 1424-418 has been steadily increasing its luminosity since August 2017 and is now (2018-01-21) at its historic recorded maximum of J=13.73 +/- 0.05. These observations were performed with the REM telescope in La Silla within the framework the TANAMI collaboration (http://pulsar.sternwarte.uni-erlangen.de/tanami/) monitoring of a sample of gamma-ray loud southern hemisphere blazars. Photometry was made with IRAF/apphot using 10 comparison stars from the 2MASS catalog.

Our NIR light curve is very well correlated with the gamma-ray light curve publicly available from the Large Area Telescope (LAT) instrument on the Fermi Gamma-ray Space Telescope (see https://fermi.gsfc.nasa.gov/ssc/data/access/lat/msl_lc/). A gamma-ray flare was also recently reported by AGILE (ATel#11222).

Our NIR/optical monitoring will continue at least for the current year and possible further activity will be reported using this and other platforms.

We note that this source, during a previous multiwavelength outburst, has provided a high-energy fluence high enough to explain the IC35 `Big Bird' neutrino (Aartsen et al. 2014, Phys. Rev. Letters 113, 101,101; Kadler et al. 2016, Nature Phys. 12, 807). We encourage multi-messenger observations and analyses of PKS 1424-418 during this active state.