Recent outburst of Cygnus X-3 observed with the Nasu telescope array at 1.4 GHz
ATel #13866; K. Tsubono (Univ. Tokyo), K. Asuma (Asaka High School), K. Niinuma (Yamaguchi Univ.), K. Takefuji (JAXA), T. Aoki (Tonan High School) and T. Daishido (Waseda Univ.)
on 14 Jul 2020; 06:37 UT
Credential Certification: Kimio Tsubono (tsubono@phys.s.u-tokyo.ac.jp)
Subjects: Radio, Binary, Black Hole, Transient
A new activity of Cygnus X-3 was reported by the RATAN-600 team (ATel #13835). The Nasu telescope array also detected a sudden increase of the flux from Cygnus X-3 on June 26 17:07 UT at 1.4 GHz. After the appearance of the flare, a single peak was observed to form for 13 days. The peak flux density was about 1.5 Jy observed on June 30. This peak flux density is rather low compared with the reported peak of 6 Jy at 11 GHz observed with the RATAN-600 radio telescope. An observed light curve of Cygnus X-3 at 1.4 GHz including the outburst period for 13 days can be shown in the figure below.
In the past two years, four outbursts from Cygnus X-3 were observed; they are in 2019 April, 2019 June, 2020 February and 2020 June (ATel #12700, #12880, #13470). Recent increasing frequency of the flares could suggest a possible new phase of the activity in Cygnus X-3.
The Nasu telescope array is a spatial fast Fourier transform (FFT) interferometer consisting of eight linearly aligned antennas with 20 m spherical dishes. This type of interferometer was developed to survey transient radio sources with an angular resolution as high as that of a 160 m dish with a field of view as wide as that of a 20 m dish.
Recent light curve of Cygnus X-3 observed at 1.4 GHz