S-CUBED confirms the brightening of the candidate Be/X-ray Binary RX J0032.9-7348
ATel #16900; T. M. Gaudin, J. A. Kennea (PSU), M. J. Coe (Southampton), P. A. Evans (Leicester)
on 11 Nov 2024; 21:18 UT
Credential Certification: Jamie A. Kennea (kennea@astro.psu.edu)
Subjects: X-ray, Binary, Neutron Star, Transient
Referred to by ATel #: 16930
The candidate Be/X-ray Binary system RX J0032.9-7348 (ATEL #16880) has been detected in 2 observations conducted by the Swift SMC Survey (S-CUBED) over the past month. This system was first detected by S-CUBED on 22 October 2024 with a 0.3-10 keV band flux of 1.46 x 10^-11 erg/cm^2/s. The most recent detection, obtained by Swift on 11 November 2024, shows that the source has since brightened to a 0.3-10 keV flux of 2.77 x 10^-11 erg/cm^2/s. The time-averaged spectrum of both observations is best fit to an absorbed power law with a photon index of 0.7 (+0.5, -0.4) and a column density of NH = 4.2 (+29.9, - 4.2) x 10^20 cm^-2.
Using S-CUBED data, we can refine the localization of this source to a new position of:
R.A. = 00:32:59.30 (8.22459d),
Dec. = -73:48:28.1 (-73.8078d)
with a 90% confidence error region of 4.3 arc-seconds. This new position places RX J0032.9-7348 within 5â of two early-type stars. One of these stars is the B0.5V star GSC 09141-01338 (Evans et al., 2004). The other is marked as Object 1 in Figure 1a of Stevens el al. (1999), where it is observed to have an emission feature that corresponds to the Balmer Series Hydrogen alpha line. However, those authors were searching a large ROSAT error region and warned that there were many such H-alpha emitters in the region. At this time, the exact optical counterpart cannot be determined. Further observations are required to distinguish between the two stars.
