Radio detection of 4U1630-47 during March 2020 outburst with MeerKAT

ATel #13592; Julien N. Girard (CEA-Saclay), Evangelia Tremou (Observatoire de Paris), Rob Fender (Oxford & UCT), Patrick Woudt (UCT), James Miller-Jones (Curtin) on behalf of the ThunderKAT collaboration
on 26 Mar 2020; 12:08 UT
Credential Certification: Julien N. Girard (julien.girard@cea.fr)

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As part of the ThunderKAT Large Survey Programme (Fender et al.2017, arXiv:1711.04132), we observed the radio counterpart of the candidate black hole X-ray binary reported in recent ATEL #13564. Despite showing recurrent outburst activity (e.g. ATel#2363, ATel#9427, ATel#11771, and associated ATels), this observation is one of the few existing radio observations on this source (e.g. see Hjellming et al., 1999, ATel#2370). Radio measurements with MeerKAT (61 antennas) started on MJD 58929.08 (2020-03-21 02:02:55 UTC) for 15min. We observed the phase calibrator J1744-5144 for 2 minutes before and after a 15-minute scan on 4U1630-47. J1939-6342 was used as the primary flux and bandpass calibrator. Data were taken at a central frequency of 1.28 GHz with a bandwidth of 856 MHz over 4096 channels. Calibration and imaging were performed using standard techniques and direction-dependent calibration and imaging (Tasse et al. 2018, A&A 611, A87) to account for the effect of the strong and the significant extended source present in the field. We detect the source at a peak flux level of 4.74 +/-0.11 mJy/beam (corresponding to an SNR of ~16 associated with a local r.m.s. noise of 0.097 mJy/beam due to the presence of nearby diffuse emission). The fitted position of RA=16h34m01.6s +/-0.5s and DEC=-47d23m34.7s +/-0.5s is consistent with the previously known radio position of the source. ThunderKAT will run for 5 years and targets X-ray binaries, Cataclysmic Variables, Supernovae and Gamma-Ray Bursts. As part of this programme we perform weekly monitoring observation of all bright, active, southern hemisphere X-ray binaries in the radio band. For further information on this programme please contact Rob Fender and/or Patrick Woudt. We thank the staff at the South African Radio Astronomy Observatory (SARAO) for scheduling and carrying out these observations. The MeerKAT telescope is operated by SARAO, which is a facility of the National Research Foundation, and agency of the Department of Science and Technology. We acknowledge the use of the Inter-University Institute for Data Intensive Astronomy (IDIA) data intensive research cloud for data processing. IDIA is a South African university partnership involving the University of Cape Town, the University of Pretoria and the University of the Western Cape. We acknowledge the use of the Nancay Data Center, hosted by the Nancay Radio Observatory (Observatoire de Paris-PSL, CNRS, Universite d'Orleans), and also supported by Region Centre-Val de Loire.