The NICER View of the 2020 Burst Storm and Persistent Emission of SGR 1935+2154

Abstract

We report on NICER observations of the Magnetar SGR~1935+2154, covering its 2020 burst storm and long-term persistent emission evolution up to $\sim 90$ days post outburst. During the first 1120~seconds taken on April 28 00:40:58 UTC we detect over 217 bursts, corresponding to a burst rate of $>0.2$ bursts s${}^{-1}$. Three hours later the rate is at 0.008 bursts s${}^{-1}$, remaining at a comparatively low level thereafter. The $T_{90}$ burst duration distribution peaks at 840~ms; the distribution of waiting times to the next burst is fit with a log-normal with an average of 2.1 s. The 1-10 keV burst spectra are well fit by a blackbody, with an average temperature and area of $kT=1.7$ keV and $R^2=53$ km${}^2$. The differential burst fluence distribution over $\sim 3$ orders of magnitude is well modeled with a power-law form $dN/dF\propto F^{-1.5\pm 0.1}$. The source persistent emission pulse profile is double-peaked hours after the burst storm. We find that the bursts peak arrival times follow a uniform distribution in pulse phase, though the fast radio burst associated with the source aligns in phase with the brighter peak. We measure the source spin-down from heavy-cadence observations covering days 21 to 39 post-outburst, $\dot{\nu }=-3.72(3)\times 10^{-12}$ Hz s${}^{-1}$; a factor 2.7 larger than the value measured after the 2014 outburst. Finally, the persistent emission flux and blackbody temperature decrease rapidly in the early stages of the outburst, reaching quiescence 40 days later, while the size of the emitting area remains unchanged.

Accepted for publication in the Astrophysical Journal Letters

References in corpus (18)

• A fast radio burst associated with a Galactic magnetar
• A bright millisecond-duration radio burst from a Galactic magnetar
• INTEGRAL discovery of a burst with associated radio emission from the magnetar SGR 1935+2154
• Repeating Fast Radio Bursts from Magnetars with Low Magnetospheric Twist
• The Prelude to and Aftermath of the Giant Flare of 2004 December 27: Persistent and Pulsed X-ray Properties of SGR 1806-20 from 1993 to 2005
• A Swift gaze into the 2006 March 29th burst forest of SGR 1900+14
• Detection of two bright radio bursts from magnetar SGR 1935+2154
• The Five Year Fermi/GBM Magnetar Burst Catalog
• Radio continuum and polarization study of SNR G57.2+0.8 associated with magnetar SGR1935+2154
• Burst properties of the most recurring transient magnetar SGR J1935+2154
• The 2008 May burst activation of SGR 1627-41
• On the Distance of SGR 1935+2154 Associated with FRB 200428 and Hosted in SNR G57.2+0.8
• Constraints on the Emission and Viewing Geometry of the Transient Anomalous X-ray Pulsar XTE J1810-197
• Deep NuSTAR and Swift Monitoring Observations of the Magnetar 1E 1841-045
• The X-ray reactivation of the radio bursting magnetar SGR 1935+2154
• The Sleeping Monster: NuSTAR observations of SGR 1806-20, 11 years after the Giant Flare
• Pulse Phase-coherent Timing and Spectroscopy of CXOU J164710.2-45521 Outbursts
• Simultaneous magnetic polar cap heating during a flaring episode from the magnetar 1RXS J170849.0-400910

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