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Project Summary

The Milky Way's dominant star-forming structure, the Galactic Ring, remains largely unexplored. Advances in mm-wave array technology permit a fresh examination of the Galactic Ring. Using the SEQUOIA multi-pixel array receiver on the FCRAO 14 m telescope, we are conducting a new molecular line survey of the inner Galaxy, the Boston University-FCRAO Galactic Ring Survey (GRS).

Integrated ¹³CO J=1-0 intensity from the first 16 square degrees covered by the GRS.

Compared with previous molecular line surveys of the inner Galaxy, the GRS offers excellent sensitivity (<0.4 K), higher spectral resolution (0.2 km/s), comparable or better angular resolution (46") and sampling (22"), and the use of ¹³CO (1-0), a better column density tracer than the commonly observed ¹²CO.

• How many molecular clouds does the 5 kpc ring contain? What are their properties? Do molecular clouds in the star-forming ring differ from clouds elsewhere in the Galaxy?
• What are the spatial distribution, luminosity function, and initial mass function of the young stars forming both inside and outside the ring?
• How does the star-formation process within the ring differ from that near the Sun and in the outer Galaxy?
• Is star-formation in the ring more efficient, or has the Galaxy simply collected a larger number of star-forming clouds at this Galactocentric radius?
• What is the ring's structure? Is it a true annulus, or does it consist of tightly wound spiral arms? Is it axisymmetric?
• What is the ring's origin? Is it associated with dynamical resonances in the Galaxy? What is the relation between the 5 kpc ring and the Galaxy's central bar?

In detail we will:

• Catalog the molecular clouds and cloud cores.
• Establish kinematic distances to many clouds and their associated Young Stellar Objects.
• Determine their sizes, luminosities, and distributions.
• Determine the structure of the inner Milky Way, especially that of the 5 kpc ring.
• Investigate the structure of molecular clouds.

Please use the following reference for GRS data in your publications:

\bibitem[Jackson et al.(2006)]{2006ApJS..163..145J} Jackson, J.~M., et al.\ 2006, \apjs, 163, 145

Please use the following acknowledgement in any published material that makes use of GRS data:

This publication makes use of molecular line data from the Boston University-FCRAO Galactic Ring Survey (GRS). The GRS is a joint project of Boston University and Five College Radio Astronomy Observatory, funded by the National Science Foundation under grants AST-9800334, AST-0098562, & AST-0100793

GRS Web Statistics!

The GRS is supported by the NSF via grants AST-9800334, AST-0098562 and AST-0507657

The FCRAO is supported by the NSF via AST-0100793 and AST-0228993.