High Spatial/Temporal Resolution Chandra Follow-up of the 2015 outburst of the X-ray pulsar SMC X-2
Abstract
Accretion and propeller are the major processes driving the pulsar evolution. SMC X-2, a 2.37s X-ray pulsar (Corbet+ 2000), is one of a few important examples showing strong accretion outbursts and low accretion propeller quiescences, occasionally. 2 close (2") possible optical counterparts, a variable brighter Oe and a stable fainter Be, have been reported (Schmidtke+ 2006). In 2015 Sep, Swift/BAT and MAXI/GSC independently detected an outburst at 15 mCrab. A rapid XRT ToO confirms the result with the best ever accurate localization at <3.6". But still, depending on how the XRT astrometry is done, both the reported counterparts can be real. While our analysis on the most recent XRT data (WT) tentatively shows the spin period is by 0.001s faster than the one detected by RXTE/ASCA in 2000, a more sensitive data is required to confirm this. We thus request a 2.8ks timing mode HRC-S observation to 1) determine the optical companion and 2) verify spin-up history over the last 15 years.
- Publication:
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Chandra Proposal
- Pub Date:
- September 2014
- Bibcode:
- 2014cxo..prop.4806L