MeerKAT radio non-detection of the black hole transient V4641 Sgr during its outburst
ATel #13471; Xian Zhang, Wenfei Yu (Shanghai Astronomical Observatory), Rob Fender (University of Oxford), Patrick Woudt (University of Cape Town), James Miller-Jones (Curtin University), on behalf of the ThunderKAT collaboration
on 13 Feb 2020; 07:49 UT
Credential Certification: Wenfei Yu (wenfei@shao.ac.cn)
Subjects: Radio, Black Hole, Transient
Referred to by ATel #: 14968
Following the report of the new outburst of the black hole transient V4641 Sgr (also known as SAX J1819.3-2525), which has been detected by MAXI/GSC since 2020 January 7 (Atel #13431), we performed two MeerKAT observations on February 1 and 8, with a bandwidth of 856 MHz centered at 1.284 GHz and on-source time of 15 minutes each. In the data reduction, J1939-6342 was set as the flux calibrator and J1833-2103 as the phase calibrator. We did not detect V4641 Sgr in either epoch with 3 sigma upper limits of ~100 microJy/beam, implying radio jet quenching for the source. This is consistent with the NuSTAR DDT observation (Atel #13431) , in which the source was suggested to evolve in a soft state.
The observations for V4641 Sgr were conducted by the MeerKAT radio array, as part of the ThunderKAT Large Survey Programme (http://adsabs.harvard.edu/abs/2017arXiv171104132F ).
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 observations 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 their rapid scheduling of these observations. The MeerKAT telescope is operated by SARAO, which is a facility of the National Research Foundation, an agency of the Department of Science and Technology.
