Clump 2 - an inner spiral arm?

The "Clump 2" molecular cloud complex near the galactic center at (l, b, v ≈ (3°, +0°.2, +20 to +150 km s⁻¹) has been studied with the J = 1→0 rotational transitions of ¹²CO and ¹³CO and the J = 2→1 transition of CS. The molecular gas is distributed in a complex of 16 individual CS emitting cores, each having densities in excess of 2×10⁴cm⁻³, and masses greater than 5×10⁵M_sun;. All the molecular emission is at velocities permitted by galactic rotation; the authors suggest that the extraordinary line width of the complex is the signature of a dust lane or inner spiral arm in a barlike potential.