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On 2020 October 10, the Burst Alert Telescope (BAT) on board the Neil
Gehrels Swift Observatory triggered on a short, hard X-ray burst.
Prompt observations with the Swift X-ray Telescope (XRT) localized a
new uncatalogued X-ray source, Swift J1830.7−0645. A periodic signal
at ∼10.4 s was detected in the XRT data. The burst properties, the
periodicity detected in the prompt follow-up observations, and the
proximity of the source to the Galactic plane indicated a newly
discovered magnetar in outburst. A magnetar is an isolated neutron
star powered by dissipation of their own magnetic energy, which
usually implies that they are endowed with huge magnetic fields, up to
∼10^15 gauss. A large fraction of the ∼30 magnetars known to date
have been discovered over the past two decades. The image above shows
light curves of Swift J1830.7-0645 extracted from the Swift/XRT data,
with detected X-ray bursts marked by arrows. Radio observations, with
both the Parkes 64m and Sardinia 64m radio telescopes, found no
evidence for periodic or single-pulse emission at radio frequencies.
However, the non-detection of radio pulsations is not that surprising,
as examples of both radio-loud and radio-silent magnetars have
previously been documented. More details are given in the paper by
Coti Zelati et al.
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