Published in The Astrophysical Journal, 759, 8 (2012) Preprint typeset using LATEX style emulateapj v. 5/2/11 TWO NEW BURSTING NEUTRON STAR LOW-MASS X-RAY BINARIES:

We discuss the origin of two triggers of Swift ’s Burst Alert Telescope (BAT) that occurred in 2011. The triggers were identified with Swift J185003.2–005627, a previously unknown X-ray source, and the known but unclassified X-ray transient Swift J1922.7–1716. We investigate the BAT data and follow-up observations obtained with Swift ’s X-ray and ultraviolet/optical telescopes to demonstrate that both triggers are consistent with thermonuclear X-ray bursts. This implies that both sources are neutron star low-mass X-ray binaries. The total duration of ' 7 minutes and estimated energy output of ' (3−7)×1039 erg, fall in between that of normal and intermediately long X-ray bursts. From the observed peaks of the X-ray bursts, we estimate a distance of. 3.7 kpc for Swift J185003.2–005627 and. 4.8 kpc for Swift J1922.7–1716. We characterize the outburst and quiescent X-ray properties of the two sources. They have comparable average outburst luminosities of ' 1035−36 erg s−1, and a quiescent luminosity equal to or lower than ' 2 × 1032 erg s−1 (0.5–10 keV). Swift J185003.2–005627 returned to quiescence ' 20 d after its BAT trigger, while Swift J1922.7–1716 appears to exhibit long accretion outbursts that last several months to years. We identify a unique counterpart for Swift J1922.7–1716 in the ultraviolet/optical data. Finally, we serendipitously detect a flare last-ing ' 500 s from an uncataloged X-ray/optical object that we tentatively classify as a flaring M-dwarf