A 44 Day Period in AX J1700.2-4220 from Swift/BAT Observations
ATel #2559; Robin H. D. Corbet (UMBC/NASA GSFC), Hans A. Krimm (USRA/NASA GSFC), Gerald K. Skinner (UMCP/NASA GSFC)
on 14 Apr 2010; 14:10 UT
Credential Certification: Robin Corbet (Robin.Corbet@nasa.gov)
Subjects: X-ray, Binary, Black Hole, Neutron Star, Star
AX J1700.2-4220 is a poorly studied X-ray source that may be a
high-mass X-ray binary (Negueruela & Schurch, 2007, A&A, 461, 631;
Bird et al., 2010, ApJ Supp., 186, 1). An analysis of the 15 - 50 keV
light curve of this source obtained with the Swift/BAT covering
2005-02-12 through 2010-03-30 (MJD 53,413 to 55,285) reveals highly
significant modulation at a period near 44 days.
In order to characterize the modulation we fitted a sine wave to the
light curve and derived:
Tmax (MJD) = 54342.0 (+/- 0.5) + n x 44.12 (+/- 0.04)
where Tmax is the time of maximum flux.
The mean flux is 0.0004 cts/cm2/s, equivalent to approximately 2
mCrab, and the flux is close to 100% modulated on the 44 day
period. An inspection of the folded light curve suggests that the peak
flux may actually occur slightly later than is derived from the sine
wave fit.
The presence of this periodic modulation is consistent with an HMXB
classification for the source. Additional X-ray observations near
predicted flux maximum are encouraged to search for X-ray pulsations.
This telegram made use of Swift/BAT transient monitor results provided
by the Swift/BAT team.
Scaled Map Transient Analysis for AX J1700.2-4220
