3C 279: ALMA detection of radio flare in total and polarized flux densities
ATel #11572; Seiji Kameno, Paulo Cortes, Edward Fomalont, Ruediger Kneissl, Antonio Hales, Celia Verdugo, Matias Radiszcz, Kurt Plarre, Cristian Lopez, Satoko Takahashi, Jose Fernandez, Jorge Garcia, Itziar De Gregorio, Miguel Sanchez Portal, Eric Villard, Charles Hull, Hugo Messias, Loreto Barcos, Daniel Walker David Rebolledo, Gabriel Marinello, John Carpenter, Elizabeth Humphreys, Stuartt Corder (Joint ALMA Observatory), Ruben Herrero-Illana, Adele Plunket, Andres Perez, Claudia Agliozzo, Chentao Yang (European Southern Observatory)
on 25 Apr 2018; 03:32 UT
Credential Certification: Seiji Kameno (seiji.kameno@alma.cl)
Subjects: Millimeter, Sub-Millimeter, AGN, Blazar
The Atacama Large Millimeter/submillimeter Array (ALMA) is monitoring full-Stokes parameters of extragalactic radio sources at 97.5, 233, and 343.5 GHz, and has detected a radio flare of J1256-0547 (3C 279) at the coordinate of RA=12:56:11.166573 DEC=-05.47.21.52515 in J2000.0. The interferometry observations were carried out using the Morita array consisting of 12 7-m antennas within the maximum baseline of 49 m. The radio source is unresolved with the synthesized beam of 14 - 4 arcsec. The preliminary data reduction for the observations during 2018 Apr 01 through Apr 23, listed in the tables below, indicates that Stokes I later than Apr 17 significantly increased by 15%, 24%, and 29% at the frequencies of 97.5, 233, and 343.5 GHz, respectively. The linearly polarized flux density, sqrt(Q^2 + u^2), has increased by 80%, 68%, and 42%, respectively. The electric vector position angle (EVPA) also changed by 0.2 rad (11 degrees). The flux densities in the tables involve ~3-5% systematic errors. The radio flare is synchronized with the gamma-ray flare event reported by Fermi-LAT on April 17 (ATel #11542) and MAGIC on April 18 (ATel #11545).
97.5 GHz
|Date | I| Q| U| V| EVPA|
|UT | Jy | Jy | Jy | Jy | rad |
|:--------------|------:|------:|------:|------:|-----:|
|2018 Apr 02.16 | 12.886| -0.277| 1.117| -0.001| 0.907|
|2018 Apr 02.16 | 12.931| -0.266| 1.164| 0.003| 0.898|
|2018 Apr 11.10 | 12.553| -0.020| 0.895| -0.008| 0.796|
|2018 Apr 11.10 | 12.591| -0.022| 0.882| -0.007| 0.798|
|2018 Apr 13.26 | 14.206| 0.240| 1.467| -0.015| 0.704|
|2018 Apr 13.28 | 13.558| 0.206| 1.392| -0.018| 0.712|
|2018 Apr 17.12 | 13.639| 0.180| 1.167| -0.011| 0.709|
|2018 Apr 17.12 | 13.609| 0.179| 1.183| -0.008| 0.710|
|2018 Apr 17.17 | 14.691| 0.298| 1.499| -0.014| 0.687|
|2018 Apr 17.17 | 14.675| 0.289| 1.505| -0.015| 0.691|
|2018 Apr 20.26 | 14.688| 0.541| 1.768| -0.025| 0.637|
|2018 Apr 23.05 | 13.680| 0.279| 1.088| -0.013| 0.660|
|2018 Apr 23.05 | 13.687| 0.279| 1.092| -0.020| 0.660|
233 GHz
|Date | I| Q| U| V| EVPA|
|UT | Jy | Jy | Jy | Jy | rad |
|:--------------|------:|------:|------:|------:|-----:|
|2018 Apr 11.24 | 8.139| -0.108| 0.770| 0.068| 0.855|
|2018 Apr 13.31 | 8.973| 0.082| 0.927| -0.001| 0.741|
|2018 Apr 17.18 | 8.926| 0.396| 1.045| 0.008| 0.604|
|2018 Apr 19.08 | 10.069| 0.313| 1.256| -0.004| 0.663|
|2018 Apr 19.08 | 9.941| 0.316| 1.263| -0.003| 0.663|
|2018 Apr 20.23 | 9.855| 0.266| 1.155| -0.004| 0.672|
|2018 Apr 23.13 | 9.649| 0.333| 1.176| 0.002| 0.647|
343.5 GHz
|Date | I| Q| U| V| EVPA|
|UT | Jy | Jy | Jy | Jy | rad |
|:--------------|------:|------:|------:|------:|-----:|
|2018 Apr 01.32 | 6.595| -0.102| 0.858| 0.014| 0.844|
|2018 Apr 02.12 | 6.437| -0.078| 0.745| 0.004| 0.838|
|2018 Apr 02.12 | 6.412| -0.113| 0.739| -0.006| 0.861|
|2018 Apr 12.31 | 6.318| -0.059| 0.828| 0.014| 0.821|
|2018 Apr 17.04 | 7.121| 0.208| 0.884| 0.007| 0.670|
|2018 Apr 17.04 | 7.085| 0.188| 0.874| 0.001| 0.679|
|2018 Apr 20.28 | 8.300| 0.272| 1.088| 0.018| 0.663|
Full Stoles parameters of 3C 279