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Recent radio activity of the Fermi blazar CTA 102

ATel #4449; I. Myserlis, E. Angelakis, L. Fuhrmann, V. Karamanavis, I. Nestoras, T. P. Krichbaum, J. A. Zensus (F-GAMMA team, MPIfR, Bonn, Germany), H. Ungerechts, A. Sievers (IRAM, Granada, Spain)
on 2 Oct 2012; 12:15 UT
Credential Certification: Emmanouil Angelakis (angelaki@mpifr-bonn.mpg.de)

Subjects: Radio, Millimeter, AGN, Blazar, Quasar

Referred to by ATel #: 9884

We report the recent activity (raising flux density) seen in the monitored blazar CTA 102 (J2232+1143, RA= 22:32:36, DEC=+11:43:51 in J2000) as recorded within the framework of the F-GAMMA program responding to ATels #4397, #4437 (optical) and #4409 (gamma).

Long term behaviour:
CTA 102 has been monitored since January 2007 at 11 frequencies between 2.64 and 228.39 GHz. Its light curves above 4.85 GHz are dominated by one major event peaking between 2009 and 2010 which propagated from high towards lower frequencies. This can be seen in its light curves at: low, intermediate and higher frequencies (or all frequencies together), as well as the temporal evolution of its spectrum.

Recent activity:
From the high frequencies light curves it can be seen that the source has recently come into a new activity phase after a long minimum between MJD 55650 and 56100. For instance, at 86.24 GHz (3 mm) the flux density increased from 1.6 (MJD: 55918.082) to 4.4 Jy (MJD: 56175.536). At intermediate and low frequencies the source hasn't shown any signs of increasing activity yet (around MJD 56200), except the flux density increase at 23.05 GHz from 1.9 (MJD: 56110.273) to 2.8 Jy (MJD: 56185.872). The weekly-averaged public Fermi light curve (100 MeV - 300 GeV) indicates a rapid increase in flux density around MJD: 56100, which can be associated with the recent activity seen in radio frequencies.

The source will be continuously monitored and possible future activity will be reported through the current platform.

F-GAMMA program:
F-GAMMA (Fermi-GST AGN Multi-frequency Monitoring Alliance) program is the coordinated effort of several observatories and research teams to probe AGN physics through the multi-frequency monitoring approach. The core program relies on monthly observations with the Effelsberg 100-m radio telescope (operating at 8 frequencies between 2.6 and 43 GHz), the IRAM 30-m telescope (observing at 86 and 142 GHz) and additional measurements with the APEX 12-m telescope (operating at 345 GHz). The core sample consists of roughly 60 Fermi_GST/LAT monitored blazars. The data are taken simultaneously within 40 minutes for Effelsberg and 10 minutes for the IRAM telescope while the cross-station coherency is of order of 10 days. Data products are publicly accessible here. For more details, visit:

F-GAMMA program page