MeerKAT detects radio emission from black hole X-ray binary GS 1354-64

ATel #17582; Chiara Salvaggio (INAF-OAB), Noa Grollimund (Universite Paris Cite & CEA Saclay), Francesco Carotenuto (INAF-OAR), Stephane Corbel (Universite Paris Cite & CEA Saclay), Rob Fender (Oxford University), Sara Motta (INAF-OAB), on behalf of the X-KAT collaboration
on 7 Jan 2026; 16:54 UT
Credential Certification: Chiara Salvaggio (chiara.salvaggio@inaf.it)

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The black hole X-ray binary GS 1354-64 entered a new outburst in late December 2025 detected by MAXI (ATel #17563). Following the X-ray trigger, we initiated follow-up radio observations with the MeerKAT radio telescope as part of the X-KAT programme. Here, we report on the detection of radio emission from GS 1354-64.

Radio observations were carried out at a central frequency of 1.28 GHz, with a total bandwidth of 856 MHz. We used J1939-6342 for flux and bandpass calibration, and J1424-4913 for complex gain calibration. GS 1354-64 was observed for 10 minutes on 2026-01-04 04:31:59 UTC (MJD 61044.19). We detect a radio source at the known position of GS 1354-64. Fitting for a point source in the image plane, we measure a preliminary flux density of 3.66 ± 0.03 mJy (statistical uncertainties).

Multi-wavelength observations are encouraged to study the evolution of the outburst. Further radio monitoring is planned, as well as weekly Swift observations of the target.

X-KAT is a large MeerKAT open-time programme to observe X-ray binaries in the radio band, performing weekly monitoring of bright, active systems, with capacity for higher cadence observations, and in coordination with large X-ray and optical monitoring programmes. For further information on this programme contact Rob Fender. The Swift follow-up of X-ray binaries is largely performed as part of the SwiftKAT program, which provides quasi simultaneous X-ray coverage of the X-KAT targets.