Browsing by Author "Johnston, Simon"

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    The 2022 High-energy Outburst and Radio Disappearing Act of the Magnetar 1E 1547.0–5408
    (IOP Publishing, 2023) Lower, Marcus E.; Younes, George; Scholz, Paul; Camilo, Fernando; Dunn, Liam; Johnston, Simon; Enoto, Teruaki; Sarkissian, John M.; Reynolds, John E.; Palmer, David M.; Arzoumanian, Zaven; Baring, Matthew G.; Gendreau, Keith; Göğüş, Ersin; Guillot, Sebastien; Horst, Alexander J. van der; Hu, Chin-Ping; Kouveliotou, Chryssa; Lin, Lin; Malacaria, Christian; Stewart, Rachael; Wadiasingh, Zorawar
    We report the radio and high-energy properties of a new outburst from the radio-loud magnetar 1E 1547.0−5408. Following the detection of a short burst from the source with Swift-BAT on 2022 April 7, observations by NICER detected an increased flux peaking at (6.0 ± 0.4) × 10−11 erg s−1 cm−2 in the soft X-ray band, falling to a baseline level of 1.7 × 10−11 erg s−1 cm−2 over a 17 day period. Joint spectroscopic measurements by NICER and NuSTAR indicated no change in the hard nonthermal tail despite the prominent increase in soft X-rays. Observations at radio wavelengths with Murriyang, the 64 m Parkes radio telescope, revealed that the persistent radio emission from the magnetar disappeared at least 22 days prior to the initial Swift-BAT detection and was redetected two weeks later. Such behavior is unprecedented in a radio-loud magnetar, and may point to an unnoticed slow rise in the high-energy activity prior to the detected short bursts. Finally, our combined radio and X-ray timing revealed the outburst coincided with a spin-up glitch, where the spin frequency and spin-down rate increased by 0.2 ± 0.1 μHz and (−2.4 ± 0.1) × 10−12 s−2, respectively. A linear increase in the spin-down rate of (−2.0 ± 0.1) × 10−19 s−3 was also observed over 147 days of postoutburst timing. Our results suggest that the outburst may have been associated with a reconfiguration of the quasi-polar field lines, likely signaling a changing twist, accompanied by spatially broader heating of the surface and a brief quenching of the radio signal, yet without any measurable impact on the hard X-ray properties.