NuSTAR detection of a cyclotron line in the supergiant fast X-ray transient IGR J17544-2619
Abstract
We present NuSTAR spectral and timing studies of the supergiant fast X-ray transient (SFXT) IGR J17544-2619. The spectrum is well described by an ∼1 keV blackbody and a hard continuum component, as expected from an accreting X-ray pulsar. We detect a cyclotron line at 17 keV, confirming that the compact object in IGR J17544-2619 is indeed a neutron star. This is the first measurement of the magnetic field in an SFXT. The inferred magnetic field strength, B = (1.45 ± 0.03) × 1012G (1 + z) is typical of neutron stars in X-ray binaries, and rules out a magnetar nature for the compact object. We do not find any significant pulsations in the source on time-scales of 1-2000 s.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- March 2015
- DOI:
- 10.1093/mnras/stu2495
- arXiv:
- arXiv:1407.0112
- Bibcode:
- 2015MNRAS.447.2274B
- Keywords:
-
- X-rays: binaries;
- X-rays: individual: IGR J17544-2619;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- MNRAS Accepted. 8 pages, 4 figures, 3 tables