Dimming of classical nova V1369 Cen (Nova Centauri 2013) from ATCA and ASKAP radio observations
ATel #15310; Ashna Gulati (U. Sydney), Tara Murphy (U. Sydney), Yuanming Wang (U. Sydney), James Leung (U. Sydney), Emil Lenc (CSIRO)
on 4 Apr 2022; 04:28 UT
Credential Certification: Tara Murphy (tara.murphy@sydney.edu.au)
We report radio observations of classical nova V1369 Cen, which was identified by J. Seach on 2013 December 2.692 (IAUC # 9265 , CBET #3732). Following multiwavelength observations including radio (see ATels #5685, #6058, #5966, #6413, #5639, #5649), we detected the nova with the Australian Square Kilometre Array Pathfinder telescope (ASKAP). It was observed as part of the Rapid ASKAP Continuum Survey (RACS; McConnell et al. 2021) for three different runs over 1000 days at central frequencies 0.888 GHz (1981 days post-discovery in optical), 1.36 GHz (2615 days post-discovery in optical) and 1.65 GHz (2980 days post-discovery in optical).
We conducted further radio observations with the Australia Telescope Compact Array (ATCA) on 2022 February 6 (2985 days post-discovery in optical) at frequencies 2.1, 5.5, 9.0, 16.7 and 21.2 GHz. We report the detections and 5-sigma upper limits below:
Date (UTC) | Telescope | Freq (GHz) | Flux Density (mJy)
2019-05-06 | ASKAP | 0.888 | 2.04 ± 0.04
2021-02-01 | ASKAP | 1.367 | 1.00 ± 0.18
2022-01-29 | ASKAP | 1.650 | 1.01 ± 0.25
2022-02-06 | ATCA | 2.868 | 0.81 ± 0.12
2022-02-06 | ATCA | 5.500 | 0.40 ± 0.05
2022-02-06 | ATCA | 9.000 | 0.26 ± 0.03
2022-02-06 | ATCA | 16.700 | < 0.11
2022-02-06 | ATCA | 21.200 | < 0.18
The spectral index was calculated to be -0.9 on 2022 February 6 with a weighted scatter of ~0.93 about the linear fit in radio flux v/s frequency log-log space.
We thank CSIRO staff for supporting these observations.
