TITLE:   GCN CIRCULAR
NUMBER:  45947
SUBJECT: EP261006a : MeerKAT radio observations. 
DATE:    26/10/14 10:18:12 GMT
FROM:    stephane.corbel@cea.fr

S. Corbel, N. Grollimund (Université Paris Cité & CEA Saclay), Chichuan Jin (National Astronomical Observatories), Alexis Coleiro, Zheyu Lin  (Université Paris Cité) report : 

We observed the field of the fast X-ray transient EP261006a (Lao et al. GCN 45826) with the MeerKAT radio telescope at two frequencies: L-band [central frequency: 1.284 GHz / Bandwidth:  856 MHz] and S-band [central frequency:  3.062 GHz / Bandwidth:   875 MHz]

Data were calibrated and imaged using standard procedures. J1939-6342 was used for flux density and bandpass calibration whereas J0108+0134 (L-band) /J0121+0422 (S-band) were used for complex gain calibration.

Observations were conducted on two days: 

2026-10-09 (16 min/band), 
L-band
Start: 2026-10-09 20:41:01 UTC
Central MJD 61322.87 (t-t0 = 3.12 days)

S-band
Start: 2026-10-09 19:42:28 UTC
Central MJD 61322.83 (t-t0 = 3.08 days)

and 

2026-10-11 (16 min/band)
L-band
Start: 2026-10-11 20:02:31 UTC
Central MJD 61324.84 (t-t0 = 5.10 days)

S-band
Start: 2026-10-11 18:48:18 UTC
Central MJD 61324.79 (t-t0 = 5.05 days)

By combining both observations per band, no radio source is detected at the candidate optical counterpart (Eyles-Ferris et al. GCN 45831; Wu et al. GCN 45852; Bochenek & Perley GCN 45853; Chen et al. GCN 45854) down to a preliminary 3-sigma upper limit of  39 uJy/beam (L-band) and 27  uJy/beam (S-band). This is in agreement with the concomitant non detection reported by the VLA at 10 GHz around the same period (Yadav et al. GCN 45921). 

We thank the SARAO staff for rapidly scheduling these observations. The MeerKAT telescope is operated by the South African Radio Astronomy Observatory, which is a facility of the National Research Foundation, an agency of the Department of Science and Innovation. This work has made use of the "MPIfR S-band receiver system" designed, constructed and maintained by funding of the MPI für Radioastronomie and the Max-Planck-Society.