Rational

At the first hour of 2013 a highly variable source 122222-311525 at Ra=12:22:21.63 Dec=-31:15:24.9 was discovered: Atel #4699, Atel #4700, Atel #4708, Atel #4716. It became 7 orders of magnitude brighter than it was in 2005--2012. Ashish Mahabal suggested to try to detect such an unusual object in radio. Phil Edwards observed it for 1.5 hours with ATCA.

Observations on 2013.01.07

A field around variable source 1219-309 (aka J1222-3115, SSS130101, 122222-311525 ) was observed with ATCA at [2013.01.07_18:12, 2013.01.07_19:40] UTC at [4.5, 6.5] and [8.0, 10.0] GHZ frequency bands. The array was in EW352 configuration.

Radio image of the vicinity of 1219-309 at 5.5GHz. Image rms 25μJy.

Radio image of the vicinity of 1219-309 at 9.0GHz. Image rms 35μJy.

Here results of analysis: 
#1) Sou: 1219-309  Freq: 9000  Ra: 12_22_14.71 -+  0.91  Dec: -31_13_35.5 -+ 11.30  Flux:  0.31 -+  0.04
#2) Sou: 1219-309  Freq: 9000  Ra: 12_22_20.91 -+  0.43  Dec: -31_18_47.7 -+  5.70  Flux:  1.01 -+  0.06
#3) Sou: 1219-309  Freq: 9000  Ra: 12_22_22.16 -+  0.54  Dec: -31_15_52.7 -+  7.04  Flux:  0.31 -+  0.02


#1) Sou: 1219-309  Freq: 5500  Ra: 12_22_14.64 -+  0.51  Dec: -31_13_32.5 -+  6.65  Flux:  0.54 -+  0.03
#2) Sou: 1219-309  Freq: 5500  Ra: 12_22_20.82 -+  0.27  Dec: -31_18_51.7 -+  3.54  Flux:  1.27 -+  0.03
#3) Sou: 1219-309  Freq: 5500  Ra: 12_22_22.13 -+  1.08  Dec: -31_16_01.9 -+ 13.90  Flux:  0.21 -+  0.02

#4) Sou: 1219-309  Freq: 5500  Ra: 12_22_14.33 -+  0.87  Dec: -31_07_58.7 -+ 11.50  Flux:  2.76 -+  0.22
#5) Sou: 1219-309  Freq: 5500  Ra: 12_22_17.74 -+  0.53  Dec: -31_21_05.3 -+  7.02  Flux:  1.33 -+  0.06
#6) Sou: 1219-309  Freq: 5500  Ra: 12_22_41.42 -+  0.17  Dec: -31_20_02.9 -+  1.84  Flux:  8.44 -+  0.13
Source #3 is the closest object to 122222-311525: it is 6.0" off in right ascension and 28" off in declination. It was detected at both bands. It has flux density 0.31 mJy at 5.5 GHz and spectral index -0.79.

NVSS sources within the field of view: 

??? C1218M32  295.78  719.77 122212-310802  12 22 12.62 -31 08 02.4  0.20  4.5      8.0     1.1   47.0 < 35.6  -3.6 11.1      10.0           1.77 -19.0  0.91  7.2
#1  C1218M32  294.66  697.61 122214-311334  12 22 14.17 -31 13 34.7  0.70  7.7      3.4     0.6 < 89.9 < 70.5                      S*   26  -0.06        1.04
#3? C1218M32  287.79  689.88 122222-311529  12 22 22.30 -31 15 29.6  0.56 10.1      3.5     0.6 <108.  < 54.6                               -0.13        1.05

Observations on 2013.01.17

A field around variable source 1219-309 (aka J1222-3115, SSS130101, 122222-311525 ) was observed with ATCA at 2013.01.17_12:25 and 2013.01.17_21:05 UTC at [4.5, 6.5] and [8.0, 10.0] GHZ frequency bands in two scans 40 minutes long separated by 7.5 hours. The array was in EW352 configuration.

Radio image of the vicinity of 1219-309 at 5.5GHz

Radio image of the vicinity of 1219-309 at 9.0GHz 

#1 Sou: 1219-309  Freq: 9000  Obj:  3  Ra: 12_22_14.63 -+  0.72  Dec: -31_13_36.1 -+  0.96  Flux:     0.63 -+  0.10
#2 Sou: 1219-309  Freq: 9000  Obj:  1  Ra: 12_22_20.83 -+  0.66  Dec: -31_18_41.7 -+  1.25  Flux:     0.90 -+  0.16
#3 Sou: 1219-309  Freq: 9000  Obj:  2  Ra: 12_22_22.20 -+  0.82  Dec: -31_15_56.5 -+  1.24  Flux:     0.28 -+  0.05

   Sou: 1219-309  Freq: 5500  Obj:  7  Ra: 12_22_12.95 -+  1.52  Dec: -31_09_11.9 -+  2.81  Flux:     0.78 -+  0.20
   Sou: 1219-309  Freq: 5500  Obj:  9  Ra: 12_22_13.00 -+  1.05  Dec: -31_16_25.6 -+  1.45  Flux:     0.26 -+  0.04
#1 Sou: 1219-309  Freq: 5500  Obj:  4  Ra: 12_22_14.74 -+  0.55  Dec: -31_13_34.9 -+  0.78  Flux:     0.49 -+  0.04
   Sou: 1219-309  Freq: 5500  Obj:  8  Ra: 12_22_15.94 -+  1.31  Dec: -31_06_33.6 -+  3.28  Flux:     5.37 -+  1.36
   Sou: 1219-309  Freq: 5500  Obj:  2  Ra: 12_22_17.64 -+  0.61  Dec: -31_20_55.3 -+  1.10  Flux:     1.10 -+  0.11
   Sou: 1219-309  Freq: 5500  Obj: 10  Ra: 12_22_19.24 -+  1.11  Dec: -31_13_46.0 -+  1.68  Flux:     0.20 -+  0.03
#2 Sou: 1219-309  Freq: 5500  Obj:  3  Ra: 12_22_20.84 -+  0.53  Dec: -31_18_42.9 -+  0.72  Flux:     0.70 -+  0.05
   Sou: 1219-309  Freq: 5500  Obj:  6  Ra: 12_22_21.87 -+  1.90  Dec: -31_18_01.6 -+  2.48  Flux:     0.17 -+  0.04
#3 Sou: 1219-309  Freq: 5500  Obj:  5  Ra: 12_22_22.25 -+  0.62  Dec: -31_15_56.3 -+  0.92  Flux:     0.33 -+  0.03
   Sou: 1219-309  Freq: 5500  Obj: 11  Ra: 12_22_31.69 -+  1.14  Dec: -31_10_58.6 -+  1.74  Flux:     0.51 -+  0.09
   Sou: 1219-309  Freq: 5500  Obj:  1  Ra: 12_22_41.39 -+  0.28  Dec: -31_19_30.3 -+  0.30  Flux:     5.16 -+  0.17
The closes source to 122222-311525, #3, is in 32.4". The formal uncertainties, 0.6" and 0.9" are a bit too optimistic. More realistic uncertainties will be 1.5-2". But source #3 lies 15-20σ away from source 122222-311525. This is definitely another source.

Summary

A field around 122222-311525 (aka, J1222-3115, 1219-309, SSS130101 ) was observed with ATCA on 2013.01.07 and 2013.01.17 at two 2 GHz subbands: [4.5, 6.5] and [8.0, 10.0] GHz. Image rms is 0.03 mJy at 5.5 GHz and 0.02 mJy at 9.0 GHz.

No source brighter 150 μJy was detected at 5.5 and 9.0 GHz (5σ level) in the vicinity of 122222-311525

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Last update: 2013.01.22_10:48:17
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