Detection of a cyclotron line in SXP 15.3 during its 2017 outburst
Abstract
We report the results of AstroSat and NuSTAR observations of the Be/X-ray binary pulsar SXP 15.3 in the Small Magellanic Cloud during its outburst in late 2017, when the source reached a luminosity level of ∼1038 erg s-1, close to the Eddington limit. The unprecedented broad-band coverage of the source allowed us to perform timing and spectral analysis between 3 and 80 keV. The pulse profile exhibits a significant energy dependence, and morphs from a double-peaked profile to a single broad pulse at energies >15 keV. This can be explained by a spectral hardening during an intensity dip seen between the two peaks of the pulse profile. We detect a Cyclotron Resonance Scattering Feature at ∼5 keV in the X-ray spectrum, independent of the choice of the continuum model. This indicates a magnetic field strength of 6 × 1011 G for the neutron star.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- October 2018
- DOI:
- 10.1093/mnrasl/sly141
- arXiv:
- arXiv:1807.10696
- Bibcode:
- 2018MNRAS.480L.136M
- Keywords:
-
- stars: neutron;
- pulsars: individual: SMC;
- galaxies: individual: SXP 15.3;
- X-rays: binaries;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 5 pages, 6 figures, accepted for publication in MNRAS Letters