ATA detections of radio flares from Cyg X3

ATel #16577; W. Farah (SETI Institute, UC Berkeley), J. S. Bright (Oxford), R. Fender (Oxford), A. P. V. Siemion (UC Berkeley, Oxford), A. W. Pollak (SETI Institute, UC Berkeley), D. Deboer (UC Berkeley), I. Heywood (Oxford)
on 8 Apr 2024; 03:44 UT
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Credential Certification: Wael Farah (wfarah@seti.org)

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Following observations with the Medicina and the Sardinia Radio Telescopes reported in ATel #16574, we observed the field of Cygnus X-3 with the Allen Telescope Array (ATA) on April 5 between UT 2024-04-05 20:30 and 2024-04-05 22:10 (MJD: 60405.854549 and 60405.923669), and on April 6 between UT 2024-04-06 15:49 and 2024-04-06 19:05 (MJD: 60406.658878 and 60406.795267). The flux density calibrators 3C147 and 3C295 were used to calibrate the absolute flux scale and bandpass response of the array, while interleaved observations of 2025+3343 were used to calibrate the time-dependent complex gains, with a 10 minute observation per 30 minutes on source. Calibration and imaging were performed in CASA using standard techniques.

We detect radio flaring at the position of Cygnus X-3 in the 1-10 GHz range. We provide results from April 6th, as the flux densities measured on April 5th are consistent with those observed on April 6th:

1.5 GHz: 6.6 Jy

3.0 GHz: 4.8 Jy

5.0 GHz: 3.7 Jy

6.5 GHz: 3.2 Jy

8.0 GHz: 2.8 Jy

9.5 GHz: 2.5 Jy

We assume a conservative 10% calibration uncertainty added in quadrature to the statistical error on the fit. Each observation was performed with the correlator backend with 672 MHz of bandwidth.

Further observing of the source with the ATA is planned. We thank the staff at the Hat Creek Radio Observatory for maintaining and operating the ATA. The Allen Telescope Array (ATA) refurbishment program and its ongoing operations receive substantial support from Franklin Antonio. Additional contributions from Frank Levinson, Jill Tarter, Jack Welch, the Breakthrough Listen Initiative and other private donors have been instrumental in the renewal of the ATA. Breakthrough Listen is managed by the Breakthrough Initiatives, sponsored by the Breakthrough Prize Foundation. The Paul G. Allen Family Foundation provided major support for the design and construction of the ATA, alongside contributions from Nathan Myhrvold, Xilinx Corporation, Sun Microsystems, and other private donors. The ATA has also been supported by contributions from the US Naval Observatory and the US National Science Foundation.