A Chain of Dark Clouds in Projection Against the Galactic Center

TL;DR

This study identifies a chain of dark clouds in the Galactic Center region, estimates their distance and size, and finds evidence of ongoing star formation within them.

Contribution

It introduces a new method to determine dark cloud distances using star counts and colors, revealing a significant star-forming cloud complex.

Findings

Distance estimated at 3.2-4.2 kpc

Cloud size approximately 70 pc in length

Presence of star-forming HII regions

Abstract

In the J, H, and Ks bands survey of the the Galactic Center region over an area of 2deg x 5deg, we have found many dark clouds, among which a distinguished chain of dark clouds can be identified with a quiescent CO cloud. The distances of the clouds is estimated to be 3.2-4.2 kpc, corresponding to the Norma arm by our new method to determine distance to dark clouds using the cumulative number of stars against J-Ks colors. Adopting these estimated distances, the size is about 70 pc in length and the total mass of the cloud is 6x10^4 M_solar. Three compact HII regions harbor in the cloud, indicating that star forming activities are going on at the cores of the quiescent CO cloud on the spiral arm.