Molecular Clouds in the Galactic Nucleus

Abstract

Observations of the 2.6-mm CO line have been obtained along the galactic equator covering longitudes |ℓ| ≤ 3° and velocities |V| ≤ 300 km s^(-1). The strongest emission is concentrated toward the center (|ℓ| < 1°.5) and at low velocities (<125 km s^-1)) The similarities in distribution and brightness temperature between the CO and 100-µ emissions suggest that the grains and the gas are colocated and nearly in thermal equilibrium. Kinematic models for the gas in the nucleus are briefly discussed. The mass of this gas (mostly H_2) is estimated as 10^7 - 10^8 M_⊙ within 600 pc of the center. This large mass of interstellar molecules indicates that the galactic nucleus may not be deficient in Population I material.