NICER detection of 9.29 s pulsations from RX J0209.6-7427

ATel #13309; W. Iwakiri (Chuo U.), M. T. Wolff (NRL), G. Vasilopoulos (Yale), K. Gendreau, Z. Arzoumanian, C. Markwardt, T. E. Strohmayer (NASA/GSFC), P. S. Ray (NRL), D. Altamirano (University of Southampton), T. Mihara (RIKEN), H. Negoro (Nihon U.), S. Guillot (IRAP, CNRS), G. K. Jaisawal (DTU)
on 22 Nov 2019; 19:28 UT
Credential Certification: Michael T. Wolff (Michael.Wolff@nrl.navy.mil)

Tweet

MAXI J0206-749 is a hard X-ray transient detected by MAXI/GSC (ATel #13300) in the direction of the Small Magellanic Cloud (SMC) wing. Follow-up Swift/XRT observations (ATel #13303) identified MAXI J0206-749 with the HMXB RX J0209.6-7427. The short (100s) XRT observation did not show any significant variability (ATel #13303). The last known outburst of the system occurred in 1993 November and was detected by ROSAT PSPC (Kahabka & Hilker 2005). The 1993 outburst reached a luminosity of 10³⁸ erg/s (0.1-2.4 keV band) and lasted for approximately one month.

On 2019 November 21, NICER began observations of this target. At the time of writing, a total of 2.354 ks of exposure have been obtained. The mean 0.2-10 keV source count rate is ~77 cts/sec. Pulsation searches reveal a strong 9.29 s periodicity that is visually apparent in the raw data. The fractional pulsed amplitude is 34% (0.4-8 keV). This makes the system only the second confirmed pulsar in the Magellanic Cloud bridge. The NICER spectrum between 0.5 and 10 keV is consistent with a mildly absorbed black body at low energies (kT = 0.159±0.006 keV; hydrogen column density 5.1±1.4×10²⁰ cm^-2) plus a power-law continuum with spectral index 0.78(±0.01), giving a flux in the 0.5-10 keV band of 3.7×10^-10 erg cm^-2 s^-1. NICER will continue to monitor the outburst from this source.

NICER is a 0.2-12 keV X-ray telescope operating on the International Space Station. The NICER mission and portions of the NICER science team activities are funded by NASA.