MITSuME—multicolor optical/NIR telescopes for GRB afterglows—.

Multicolor Imaging Telescopes for Survey and Monstrous Explosions (MITSuME) has been built to perform Marti-color photometry of NIR/optical afterglow covering the wavebands from Ks to g′ allowing the photometric redshift measurements up to z≈10. Two 50 cm optical telescopes are built at Akeno, Yamanashi in eastern Japan, and at OAO, Okayama in western Japan. Each telescope has a Tricolor Camera, which allows us to take simultaneous images in g′, Rc, and Ic bands. These telescopes respond automatically to GCN alerts and start taking series of tricolor images, which are immediately processed through the analysis pipeline on site. The pipeline consists of source finding, catalog matching, sky coordinates mapping to the image pixels, and photometry of the found sources. An automated search for an optical counterpart is performed. While waiting for GRBs, the MITSuME Telescopes automatically patrol pre-selected interesting objects such as AGNs and galactic transients for multiwavelength studies with Fermi (GLAST) and MAXI. We detected five GRB afterglows in a half year. In particular, we observed GRB080506 starting 117 seconds after the Swift BAT trigger. [ABSTRACT FROM AUTHOR]