Astrometry of Star Forming Region IRAS 05137+3919 in the far outer Galaxy

Mareki Honma, Tomoya Hirota, Yukitoshi Kan-ya, Noriyuki Kawaguchi, Hideyuki Kobayashi, Tomoharu Kurayama, Katsuhisa Sato

Published 2011-01-07Version 1

We present the results of astrometric observations with VERA toward the H2O maser sources in IRAS 05137+3919, which is thought to be located in the far outer Galaxy. We have derived the parallax of \pi = 0.086 +/- 0.027 mas, which corresponds to the source distance of D=11.6+5.3-2.8 kpc. Although the parallax measurement is only 3-sigma level and thus the distance uncertainty is considerably large, we can strongly constrain the minimum distance to this source, locating the source at the distance from the Sun greater than 8.3 kpc (or 16.7 kpc from the Galaxy's center) at 90% confidence level. Our results provide an astrometric confirmation that this source is located in the far outer Galaxy beyond 15 kpc from the Galaxy center, indicating that IRAS 05137+3919 is one of the most distant star-forming regions from the Galaxy center.