Dense, parsec-scale clumps near the Great Annihilator.
HODGES-KLUCK E., POUND M.W., HARRIS A.I., LAMB J.W. and HODGES M.
Abstract (from CDS):
We report on Combined Array for Research in Millimeter-Wave Astronomy and James Clerk Maxwell Telescope observations toward the Einstein source 1E 1740.7-2942, a low-mass X-ray binary commonly known as the "Great Annihilator." The Great Annihilator is known to be near a small, bright molecular cloud in a region largely devoid of emission in 12CO surveys of the Galactic center. This region is of interest because it is interior to the dust lanes which may be the shock zones where atomic gas from the HI nuclear disk is converted into molecular gas. We find that the region is populated with a large number of dense (n ∼ 105/cm3) regions of excited gas with small filling factors. The gas appears to have turbulent support and may be the result of sprays of material from collisions in the shock zone. We estimate that ~(1-3)x105 M☉ of shocked gas resides in our r ∼ 3', Δv LSR= 100 km/s field. If this gas has recently shocked and is interior to the inner Lindblad resonance of the dominant bar, it is in transit to the x2disk, suggesting that a significant amount of mass may be transported to the disk by a low filling factor population of molecular clouds with low surface brightness in larger surveys.