Program: GS-2019B-FT-208

Recently a fast X-ray transient CDF-S XT2 detected by Chandra was shown to be powered by a magnetar formed in a neutron-star neutron-star merger. This would be a new type of signal that can be synthesized with gravitational wave to probe binary neutron-star mergers. The transient was characterized by a plateau lasting for half an hour in the light curve followed by a fast decay.Through the search over the Chandra archive, we just found a probable second similar event. Unfortunately we do not have deep optical/IR images to identify its host galaxy, which is needed to check whether it is consistent with a binary neutron star merger. Therefore we propose a 2.4 hr deep IR imaging owith Gemini South around the field the flare to identify its host galaxy.