MeerKAT radio observations of the 2019 outburst of the X-ray transient MAXIJ 1807+132

ATel #13142; Xian Zhang, Wenfei Yu (Shanghai Astronomical Observatory), Rob Fender (University of Oxford), Lilia Tremou (CEA/Saclay), David Williams (University of Oxford), Patrick Woudt (University of Cape Town), James Miller-Jones (Curtin University), Sara Motta (University of Oxford)
on 28 Sep 2019; 08:52 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Wenfei Yu (wenfei@shao.ac.cn)

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We carried out two MeerKAT radio observations of the X-ray transient MAXIJ 1807+132 on September 14th and 21th, respectively. These observations were initially motivated by the detection of the new outburst from MAXI/GSC on September 10th, 2019 (Atel #13097) and the detection of the source on September 12th with Arcminute Microkelvin Imager Large Array (AMI-LA). AMI-LA conducted a radio observation toward the target at 15.5GHz and detected a source with flux density of (200 +/- 10) uJy/beam at the phase center (Atel #13107).

We observed MAXIJ1807+132 at 1.284GHz using the MeerKAT radio array, as part of the ThunderKAT Large Survey Programme ( http://adsabs.harvard.edu/abs/2017arXiv171104132F ). We report here preliminary analysis of these data.

The first observation of MAXIJ 1807+132 was performed at 1.284GHz and lasted for about 40 minutes (from 17:35:08.3 to 19:15:45.7 UTC) on September 14th, during which J1939-6342 and J1733-1304 were used as the flux calibrator and the phase calibrator, respectively. We did not detect the source, with a 3 sigma upper limit of ~120 uJy/beam. We performed the second 45-minute observation (14:31:46.3 to 16:16:55.6 UTC) on September 21st also in 1.284GHz, in which we used J1939-6342 as the flux calibrator and J1733-1304 as the phase calibrator as well. The source was not detected either, with a 3 sigma upper limit of ~90 uJy/beam.

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.