Properties of Large-Amplitude Variable Stars Detected With Two Micron All Sky Survey Public Images

Abstract

We present a catalogue of variable stars in the near-infrared wavelength detected with overlapping regions of the 2MASS public images, and discuss their properties. The investigated region is in the direction of the Galactic center (-30 < l < 20, |b| < 20), which covers the entire bulge. We have detected 136 variable stars, of which 6 are already-known and 118 are distributed in |b| < 5 region. Additionally, 84 variable stars have optical counterparts in DSS images. The three diagrams (colour-magnitude, light variance and colour-colour diagrams) indicate that most of the detected variable stars should be largeamplitude and long-period variables such as Mira variables or OH/IR stars. The number density distribution of the detected variable stars implies that they trace the bar structure of the Galactic bulge.