Potential New Flaring Activity in 3C454.3 Seen at 1.3mm

ATel #5169; Mark Gurwell (Harvard-Smithsonian Center For Astrophysics)
on 27 Jun 2013; 21:19 UT
Credential Certification: Mark A. Gurwell (mgurwell@cfa.harvard.edu)

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The Submillimeter Array (SMA) performs ongoing flux density monitoring of quasars that are typically bright in the mm/submm bands, in order to optimally choose quasars for use as interferometric calibration sources. Through this monitoring effort, we have been following increasing millimeter/submillimeter band emission from 3C454.3 (J2253+161). 3C454.3 has been in a very quiescent state in the mm/submm bands since the end of 2011 when the last major flare faded. As measured at the SMA, 3C454.3 reached a low point flux density of 1.3 Jy at 1.3mm in mid-July 2012.

The millimeter/submillimeter band flux density for 3C454.3 has been slowly but steadily increasing since July 2012, reaching 4.8+/-0.2 Jy on June 6 2013. Our most recent measurement is from 27 June 2013 (15:34 UT) and shows that the flux has jumped significantly, to 7.7+/-0.4, a rise of 60% in 3 weeks. This behavior is quite similar to the initial phases of strong mm/submm flaring seen for example in 2005, 2007 and 2009, where the flux density over several weeks rose dramatically to typically greater than 20 Jy; these flares were seen across the electromagnetic spectrum, including in gamma rays. This suggests that we may be witnessing the start of a new flare and that 3C454.3 may continue to brighten in all bands over the weeks to come. Given that strong activity is seen across the spectrum from mm to gamma rays, it is our opinion that continued monitoring of the source at all wavelengths is warranted as this potential flare progresses.

A plot of the SMA flux density history for 3C454.3 showing past flares, and the most recent uptick in brightness, is provided in the link below.

[The Submillimeter Array is a joint project between the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics, and is funded by the Smithsonian Institution (USA) and the Academia Sinica (Taiwan).]

SMA Flux Density History for 3C454.3