Resurgence in the radio flux of the magnetar XTE J1810-197

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Following its radio revival in late-2018 (Levin et al. 2019) we have performed regular timing observations of the magnetar XTE J1810-197 with the Molonglo Observatory Synthesis Telescope as part of the UTMOST project (Bailes et al. 2017).

A single bright pulse from XTE J1810-197 which reached S/N ~100.

During a recent observation on UTC 2020-06-22-14:02:29, we measured a period averaged flux density of 35 +/- 7 mJy at 835 MHz via the radiometer equation. This is approximately a factor of 2.7 times higher than the flux density of 13 +/- 5 mJy measured 5 days earlier on UTC 2020-06-17-14:22:07, and a factor of ~5 times higher than observations in February 2020. The radio intensity appears to have decayed to flux densities between 15-20 mJy in the days following the resurgence. All observations were calibrated to the flux density of the high dispersion measure pulsar PSR J1644-4559.

Flux density measurements for XTE J1810-197, showing a bright outburst in the radio flux.

Bright single pulses with peak flux densities up to 50 +/- 15 Jy were detected in most post-resurgence observations.

Further details are available in an Astronomer’s Telegram.