A Possible Phase-dependent Absorption Feature in the Transient X-Ray Pulsar SAX J2103.5+4545

Brumback MC, Hickox RC, Furst FS, Pottschmidt K, Hemphill P, Tomsick JA, Wilms J, Ballhausen R (2018)

Publication Status: Published

Publication Type: Journal article

Publication year: 2018

Journal

Astrophysical Journal American Astronomical Society

Publisher: IOP PUBLISHING LTD

Book Volume: 852

Article Number: ARTN 132

Journal Issue: 2

DOI: 10.3847/1538-4357/aa9e91

Abstract

We present an X-ray spectral and timing analysis of two Nuclear Spectroscopic Telescope Array (NuSTAR) observations of the transient Be X-ray binary SAX J2103.5+4545 during its 2016 April outburst, which was characterized by the highest flux since NuSTAR's launch. These observations provide detailed hard X-ray spectra of this source during its bright precursor flare and subsequent fainter regular outburst for the first time. In this work, we model the phase-averaged spectra for these observations with a negative and positive power law with an exponential cutoff (NPEX) model and compare the pulse profiles at different flux states. We found that the broadband pulse profile changes from a three-peaked pulse in the first observation to a two-peaked pulse in the second observation, and that each of the pulse peaks has some energy dependence. We also perform pulse-phase spectroscopy and fit phase-resolved spectra with NPEX to evaluate how spectral parameters change with pulse phase. We find that while the continuum parameters are mostly constant with pulse phase, a weak absorption feature at similar to 12 keV might, with further study, be classified as a cyclotron line, does show strong pulse-phase dependence.

Authors with CRIS profile

Jörn Wilms Professur für Astronomie und Astrophysik Ralf Ballhausen Dr.Karl-Remeis-Sternwarte Bamberg, Astronomisches Institut

Involved external institutions

University of California, Berkeley US United States (USA) (US) Massachusetts Institute of Technology (MIT) US United States (USA) (US) University of Maryland, Baltimore County US United States (USA) (US) European Space Astronomy Centre (ESAC) ES Spain (ES) Dartmouth College US United States (USA) (US)

How to cite

APA:

Brumback, M.C., Hickox, R.C., Furst, F.S., Pottschmidt, K., Hemphill, P., Tomsick, J.A.,... Ballhausen, R. (2018). A Possible Phase-dependent Absorption Feature in the Transient X-Ray Pulsar SAX J2103.5+4545. Astrophysical Journal, 852(2). https://dx.doi.org/10.3847/1538-4357/aa9e91

MLA:

Brumback, M. C., et al. "A Possible Phase-dependent Absorption Feature in the Transient X-Ray Pulsar SAX J2103.5+4545." Astrophysical Journal 852.2 (2018).

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