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arXiv · 1905.04440

NICER Observations of the 2018 Outburst of XTE J1810-197

Tolga Guver·Ersin Gogus·Eda Vurgun·Teruaki Enoto·Keith C. Gendreau·Takanori Sakamoto·Eric V. Gotthelf·Zaven Arzoumanian·Sebastien Guillot·Gaurava K. Jaisawal·Christian Malacaria·Walid A. Majid
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Abstract

We present the earliest available soft X-ray observations of XTE J1810-187, the prototypical transient magnetar, obtained 75--84 days after its 2018 outburst with the Neutron Star Interior Composition Explorer (NICER). Using a series of observations covering eight days we find that its decreasing X-ray flux is well-described by either a blackbody plus power-law or a two-blackbody spectral model. The 2-10 keV flux of the source varied from (1.206+/-0.007)x10^{-10} to (1.125+/-0.004)x10^{-10} erg s^{-1} cm^{-2}, a decrease of about 7% within our observations and 44% from that measured 7-14 days after the outburst with NuSTAR. We confirm that the pulsed fraction and spin pulse phase of the neutron star are energy dependent up to at least 8 keV. Phase resolved spectroscopy of the pulsar suggests magnetospheric variations relative to the line of sight.

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Tolga Guver, Ersin Gogus, Eda Vurgun, Teruaki Enoto, Keith C. Gendreau, Takanori Sakamoto, Eric V. Gotthelf, Zaven Arzoumanian, Sebastien Guillot, Gaurava K. Jaisawal, Christian Malacaria, Walid A. Majid. 2019-05-11. NICER Observations of the 2018 Outburst of XTE J1810-197. https://doi.org/10.3847/2041-8213/ab212d

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