The X-Ray Reactivation of the Radio Bursting Magnetar SGR J1935+2154
Date Issued
2020
Author(s)
Borghese, A.
•
Coti Zelati, F.
•
Rea, N.
•
Esposito, P.
•
•
•
Tiengo, A.
Abstract
A few years after its discovery as a magnetar, SGR J1935+2154 started a new burst-active phase on 2020 April 27, accompanied by a large enhancement of its X-ray persistent emission. Radio single bursts were detected during this activation, strengthening the connection between magnetars and fast radio bursts. We report on the X-ray monitoring of SGR J1935+2154 from ∼3 days prior to ∼3 weeks after its reactivation, using Swift, the Nuclear Spectroscopic Telescope Array (NuSTAR), and the Neutron Star Interior Composition Explorer (NICER). We detected X-ray pulsations in the NICER and NuSTAR observations, and constrained the spin period derivative to $| \dot{P}| \lt 3\times {10}^{-11}$ s s-1 (3σ c.l.). The pulse profile showed a variable shape switching between single and double-peaked as a function of time and energy. The pulsed fraction decreased from ∼34% to ∼11% (5-10 keV) over ∼10 days. The X-ray spectrum was well fit by an absorbed blackbody model with temperature decreasing from kTBB ∼ 1.6 to 0.45-0.6 keV, plus a nonthermal power-law component (Γ ∼ 1.2) observed up to ∼25 keV with NuSTAR. The 0.3-10 keV X-ray luminosity increased in less than 4 days from $\sim 6\times {10}^{33}{d}_{6.6}^{2}$ erg s-1 to about $3\times {10}^{35}{d}_{6.6}^{2}$ erg s-1 and then decreased again to $2.5\times {10}^{34}{d}_{6.6}^{2}$ erg s-1 over the following 3 weeks of the outburst, where d6.6 is the source distance in units of 6.6 kpc. We also detected several X-ray bursts, with properties typical of short magnetar bursts.
Volume
902
Issue
1
Start page
L2
Issn Identifier
2041-8205
Ads BibCode
2020ApJ...902L...2B
Rights
open.access
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