Multi-frequency radio observations of S5 0836+710 after gamma-ray outburst
ATel #7890; M. Giroletti (INAF/ORA, Bologna, Italy), S. Righini (INAF/ORA, Medicina, Italy), U. Bach (MPIfR, Bonn, Germany), F. D'Ammando (Univ. of Bologna, Italy), M. Orienti (INAF/ORA, Bologna, Italy), C. M. Raiteri (INAF/OATo, Torino, Italy), M. Villata (INAF/OATo, Torino, Italy)
on 7 Aug 2015; 15:43 UT
Credential Certification: Marcello Giroletti (giroletti@ira.inaf.it)
Subjects: Radio, AGN, Blazar, Quasar
Referred to by ATel #: 7898
We report on multi-frequency radio observations of S5 0836+710 (4C 71.07), obtained following the report of the Fermi-LAT detection of its highest-level gamma-ray outburst (ATEL #7870). The observations were carried out in the context of our Medicina-Noto radio monitoring of gamma-ray loud blazars that is part of the GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT).
We observed S5 0836+710 with the Medicina 32 m radio telescope at 5, 8.4, and 24 GHz on 2015 August 5.52UT, 5.59UT, and 6.33UT. From our preliminary analysis, we measured a flux density of 3.3 +/- 0.1 Jy at 5 GHz, 2.9 +/- 0.1 Jy at 8.4 GHz, and 2.5 +/- 0.3 Jy at 24 GHz. The corresponding near-simultaneous spectral index is 0.25 +/- 0.20 between 5 and 8.4 GHz and 0.14 +/- 0.11 between 8.4 and 24 GHz (defined by Sν∝ν-α).
A comparison with earlier observations indicates that at present the source is in a high level of activity in the radio band. A further increase is expected based on the typical radio-gamma delay for blazar flares. The radio monitoring of S5 0836+710 at Medicina continues. The next observation date is provisionally scheduled for 2015 September 10.
