Swift detects a flare from IGR J16418-4532

The Swift Burst Alert Telescope (BAT) triggered on the supergiant fast X-ray transient (SFXT) candidate IGR J16418-4532 on 2013 April 2 at 11 56 29 UT (image trigger, 552677). This is the second detection using the new Sub-threshold Interesting Source BAT trigger criteria. Swift immediately slewed to the target. Using the data set from T-119 to T+183 s from recent telemetry downlinks, we report that this is a very weak source in BAT, and as such a description of the mask-weighted light curve is problematic.