Non-detection of radio pulses from CXOU J164710.2-455216 with Murriyang

ATel #17322; Marcus E. Lower (Swinburne), Fernando Camilo (SARAO), Paul Scholz (YorkU), George Younes (UMBC-CSST/NASA Goddard), John E. Reynolds (CSIRO), John M. Sarkissian (CSIRO)
on 6 Aug 2025; 02:17 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Marcus Lower (mlower@swin.edu.au)

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Following reports of renewed bursting activity (GCN #41172, ATel #17311) and enhanced X-ray emission (ATel #17312) from the magnetar CXOU J164710.2-455216 (J1647 hereafter), we conducted a targeted search for radio pulses using the Ultra-Wideband Low (UWL; Hobbs et al. 2020) receiver system installed on Murriyang, the Parkes 64-m radio telescope.

We observed J1647 for 1798 seconds starting at UTC 2025-07-29-07:00:48. Total intensity pulsar search-mode data were collected with 256 microsecond sampling and 3328 frequency channels each 1 MHz wide covering the 704-4032 MHz UWL band. The data were searched for single pulses using the TransientX package (Men & Barr 2024) for single pulses with widths ranging between 0.5 to 100 ms and dispersion measure (DM) values of 100 to 2000 pc cm^-3. We also searched for periodic, pulsed radio emission using the fast-folding algorithm based approach implemented in the Riptide package (Morello et al. 2020). For this, we looked for signals with a period between 10.5 to 10.7 seconds over a DM range of 100 to 2000 pc cm^-3 with incremental steps of 1 pc cm^-3. Two separate runs of the periodic search were conducted on both the full 704-4032 MHz UWL band, and one focusing on the upper 2500-4032 MHz band. The latter was conducted to avoid the potential influence of pulse scatter broadening due to multi-path propagation in the ionised interstellar medium.

No significant single pulses above a S/N threshold of 10 were identified. We also did not detect any periodic radio emission in either the full-band or upper-band searches.

Using the radiometer equation, we set a tentative 2368 MHz upper-limit of 7.9 uJy on the flux density of any periodic emission (assuming a 10 percent duty cycle and limiting S/N of 7) when averaging over the full UWL band.

We thank Kaustubh Rajwade and Emma Carli for advice on searching the data using TransientX. Murriyang, CSIRO’s Parkes radio telescope, is part of the Australia Telescope National Facility which is funded by the Australian Government for operation as a National Facility managed by CSIRO. We acknowledge the Wiradjuri people as the traditional owners of the Observatory site.