The 11 years of low-activity of the magnetar XTE J1810-197

Abstract

In 2003, the magnetar XTE J1810-197 started an outburst that lasted until early 2007. In the following 11 years, the source stayed in a quiescent/low activity phase. XTE J1810-197 is one of the closest magnetars, hence its X-ray properties can be studied in detail even in quiescence and an extended monitoring has been carried out to study its long term timing and spectral evolution. Here, we report the results of new X-ray observations, taken between September 2017 and April 2018, with XMM-Newton, Chandra and Nicer. We derived a phase-connected timing solution yielding a frequency derivative of -9.26(6)x10^-14 Hz s-1. This value is consistent with that measured between 2009 and 2011, indicating that the pulsar spin-down rate remained quite stable during the long quiescent period. A spectral analysis of all the X-ray observations taken between 2009 and 2018 does not reveal significant spectral and/or flux variability. The spectrum of XTE J1810-197 can be described by the sum of two thermal components with temperatures of 0.15 and 0.3 keV, plus a power law component with photon index 0.6. We also found evidence for an absorption line at ~1.2 keV and width of 0.1 keV. Thanks to the long exposure time of the summed XMM-Newton observations, we could also carry out a phase-resolved spectral analysis for this source in quiescence. This showed that the flux modulation can be mainly ascribed to the the warmer of the two thermal components, whose flux varies by ~45 per cent along the pulse phase.

Accepted for publication in MNRAS, 7 pages, 5 figures, 3 tables

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Cited by in corpus (11)

• Wideband polarized radio emission from the newly revived magnetar XTE J1810$-$197
• Spin frequency evolution and pulse profile variations of the recently re-activated radio magnetar XTE J1810-197
• The 2018 X-ray and Radio Outburst of Magnetar XTE J1810-197
• Radio and X-ray observations of giant pulses from XTE J1810-197
• A magnetar parallax
• The X-ray evolution and geometry of the 2018 outburst of XTE J1810-197
• Observations of Radio Magnetars with the Deep Space Network
• The X-ray outburst of the Galactic Center magnetar over six years of Chandra observations
• Large polar caps for twisted magnetosphere of magnetars
• Bright X-ray and Radio Pulses from a Recently Reactivated Magnetar
• NICER Observations of the 2018 Outburst of XTE J1810-197