Extragalactic fast X-ray transient candidates discovered by Chandra (2000-2014)

Understand

Extragalactic Fast X-ray Transients (FXRTs) are short flashes of X-ray photons spanning a few seconds to hours, with an uncertain origin.

• Our ignorance about their physical mechanisms and progenitor systems is due in part to the lack of clear multi-wavelength counterparts in most cases because they only have been identified serendipitously.
• We develop a systematic search of FXRTs using a straightforward X-ray flare search algorithm, in the Chandra Source Catalog (Data Release 2.0; 169.6 Ms over 592.4 deg$^{2}$ using only observations with $|b|>10^{\circ}$ and before 2015), incorporating various multi-wavelength constraints to rule out Galactic contamination and characterize the candidates.
• We report the detection of 14 FXRT candidates from a parent sample of 214,701 sources.