Discovery of Two Galaxies Deeply Embedded in the Great Attractor Wall

摘要

We report on the discovery of two spiral galaxies located behind the southern Milky Way, within the least-explored region of the Great Attractor. They lie at ≈ , where obscuration from Milky Way stars and dust exceeds 13-15 mag of visual extinction. The galaxies were the most prominent of a set identified using mid-infrared images of the low-latitude (|b| < 1°) Spitzer Legacy program Galactic Legacy Infrared Mid-Plane Survey Extraordinaire. Follow-up H I radio observations reveal that both galaxies have redshifts that place them squarely in the Norma Wall of galaxies, which appears to extend diagonally across the Galactic plane from Norma in the south to Centaurus/Vela in the north. We report on the near-infrared, mid-infrared, and radio properties of these newly discovered galaxies and discuss their context in the larger view of the Great Attractor. The work presented here demonstrates that mid-infrared surveys open up a new window to study galaxies in the zone of avoidance.