Explaining the asymmetric line profile in Cepheus X-4 with spectral variation across pulse phase

Beitrag in einer Fachzeitschrift


Details zur Publikation

Autorinnen und Autoren: Bhargava Y, Bhalerao V, Ballhausen R, Furst F, Pottschmidt K, Tomsick JA, Wilms J
Zeitschrift: Monthly Notices of the Royal Astronomical Society
Verlag: OXFORD UNIV PRESS
Jahr der Veröffentlichung: 2019
Band: 482
Heftnummer: 3
Seitenbereich: 2902-2912
ISSN: 0035-8711
eISSN: 1365-2966


Abstract

The high mass X-ray binary Cepheus X-4, during its 2014 outburst, showed evidence for an asymmetric cyclotron line in its hard X-ray spectrum. The 2014 spectrum provides one of the clearest cases of an asymmetric line profile among all studied sources with Cyclotron Resonance Scattering Features (CRSF). We present a phase-resolved analysis of NuSTAR and Suzaku data taken at the peak and during the decline phases of this outburst. We find that the pulse-phased resolved spectra are well-fit by a single, symmetric cyclotron feature. The fit parameters vary strongly with pulse phase: most notably the central energy and depth of the cyclotron feature, the slope of the power-law component, and the absorbing column density. We synthesise a 'phase averaged' spectrum using the best-fitting parameters for these individual pulse phases, and find that this combined model spectrum has a similar asymmetry in the cyclotron features as discovered in phase-averaged data. We conclude that the pulse phase resolved analysis with simple symmetric line profiles when combined can explain the asymmetry detected in the phase-averaged data.


FAU-Autorinnen und Autoren / FAU-Herausgeberinnen und Herausgeber

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


Einrichtungen weiterer Autorinnen und Autoren

European Space Astronomy Centre (ESAC)
Indian Institute of Technology Bombay
Inter-University Centre for Astronomy and Astrophysics (IUCAA)
University of California, Berkeley
University of Maryland, Baltimore County


Zitierweisen

APA:
Bhargava, Y., Bhalerao, V., Ballhausen, R., Furst, F., Pottschmidt, K., Tomsick, J.A., & Wilms, J. (2019). Explaining the asymmetric line profile in Cepheus X-4 with spectral variation across pulse phase. Monthly Notices of the Royal Astronomical Society, 482(3), 2902-2912. https://dx.doi.org/10.1093/mnras/sty2823

MLA:
Bhargava, Yash, et al. "Explaining the asymmetric line profile in Cepheus X-4 with spectral variation across pulse phase." Monthly Notices of the Royal Astronomical Society 482.3 (2019): 2902-2912.

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Zuletzt aktualisiert 2019-26-07 um 09:34