A radiatively-quiet glitch and anti-glitch in the magnetar 1E 2259+586

Abstract

We report on the timing and spectral properties of the soft X-ray emission from the magnetar 1E 2259+586 from January 2013, $\sim 8$ months after the detection of an anti-glitch, until September 2019, using the Neil Gehrels Swift and NICER observatories. During this time span, we detect two timing discontinuities. The first, occurring around 5 years after the April 2012 anti-glitch, is a relatively large spin-up glitch with a fractional amplitude $\Delta \nu /\nu =1.24(2)\times 10^{-6}$. We find no evidence for flux enhancement or change in the spectral or pulse profile shape around the time of this glitch. This is consistent with the picture that a significant number of magnetar spin-up glitches are radiatively-quiet. Approximately 1.5 years later in April 2019, 1E 2259+586 exhibited an anti-glitch with spin-down of a fractional amplitude $\Delta \nu /\nu =-5.8(1)\times 10^{-7}$; similar to the fractional change detected in 2012. We do not, however, detect any change to the pulse-profile shape or increase in the rms pulsed flux of the source, nor do we see any possible bursts from its direction around the time of the anti-glitch; all of which occurred during the 2012 event. Hence, similar to spin-up glitches, anti-glitches can occur silently. This may suggest that these phenomena originate in the neutron star interior, and that their locale and triggering mechanism do not necessarily have to be connected to the magnetosphere. Lastly, our observations suggest that the occurrence rate of spin-up and spin-down glitches is about the same in 1E 2259+586, with the former having a larger net fractional change.

Accepted for publication in the Astrophysical Journal Letters -- Acknowledgment fixed to note the correct grant number

References in corpus (14)

• An online repository of Swift/XRT light curves of GRBs
• Magnetars: Properties, Origin and Evolution
• Magnetar-like Emission from the Young Pulsar in Kes 75
• Discovery of luminous pulsed hard X-ray emission from anomalous X-ray pulsars 1RXS J1708-4009, 4U 0142+61 and 1E 2259+586 by INTEGRAL and RXTE
• Detection of 107 glitches in 36 southern pulsars
• A Magnetar-like Outburst from a High-B Radio Pulsar
• Magnetar-like X-ray Bursts from a Rotation Powered Pulsar, PSR J1119-6127
• The Sleeping Monster: NuSTAR observations of SGR 1806-20, 11 years after the Giant Flare
• NuSTAR observations of X-ray bursts from the magnetar 1E 1048.1-5937
• A glitch and an anti-glitch in the anomalous X-ray pulsar 1E 1841-045
• Swift observations of two outbursts from the magnetar 4U 0142+61
• Anti-glitches within the standard scenario of pulsar glitches
• Simultaneous magnetic polar cap heating during a flaring episode from the magnetar 1RXS J170849.0-400910
• Detailed X-ray spectroscopy of the magnetar 1E 2259+586

Cited by in corpus (5)

• The dissipation of toroidal magnetic fields and spin-down evolution of young and strongly magnetized pulsars
• Fermi-GBM Observations of the SGR J1935+2154 Burst Forest
• Anti-glitches in accreting pulsars from superfluid vortex avalanches
• Magnetar outburst and spin-down glitch
• On the radiation-loud and radiation-quiet anti-glitches in magnetar 1E 2259+586