MeerKAT 1.28 GHz upper limits on XTE J1739-285 during its 2019 outburst
ATel #13177; Joe Bright (Oxford), Rob Fender (Oxford, UTC), Patrick Woudt (UCT), James Miller-Jones (Curtin)
on 9 Oct 2019; 09:36 UT
Credential Certification: Joe Bright (joe.bright@physics.ox.ac.uk)
Subjects: Radio, Neutron Star, Transient
Referred to by ATel #: 13656
As part of the ThunderKAT Large Survey Program, we observed the field of the (tentative) high rotation rate neutron star X-ray transient XTE J1739-285 (Kaaret et. al 2007, however see Chakrabarty 2008) with 59 antennas of the MeerKAT radio telescope on MJD 58755.62 (2019-09-29 14:54:18.7 UTC), 2.33 days after a new outburst was detected by INTEGRAL (ATel #13138). We observed the phase calibrator J1830-3602 for 2 minutes before and after a 15 minute scan on the target field. J1939-3602 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.
We report a 3-sigma upper limit of 210uJy at the position of XTE J1739-285. The proximity to Sgr A* means we do not reach the usual noise limit of around 30uJy typically achieved during the ThunderKAT monitoring program with a similar observing strategy. Assuming a maximum distance of 12 kpc (ATel #784) this corresponds to a 5 GHz radio luminosity upper limit of around 2e26 erg/s, where we assume a flat spectrum between our observing frequency and 5 GHz.
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 scheduling and carrying out 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. 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.
