A giant star-forming region in a metal-poor dwarf galaxy has been observed in optical lines with the 10-m Gran Telescopio Canarias and in the emission line of CO ( 1-0 ) with the NOEMA mm-wave interferometer .
The metallicity was determined to be 12 + \log ( { O / H } ) = 7.83 \pm 0.09 , from which we estimate a conversion factor of \alpha _ { CO } \sim 100 M _ { \odot } { pc } ^ { -2 } \left ( K km s ^ { -1 } % \right ) ^ { -1 } and a molecular cloud mass of \sim 2.9 \times 10 ^ { 7 } M _ { \odot } .
This is an enormous concentration of molecular mass at one end of a small galaxy , suggesting a recent accretion .
The molecular cloud properties seem normal : the surface density , 120 M _ { \odot } pc ^ { -2 } , is comparable to that of a standard giant molecular cloud , the cloud ’ s virial ratio of \sim 1.8 is in the star-formation range , and the gas consumption time , 0.5 Gyr , at the present star formation rate is typical for molecular regions .
The low metallicity implies that the cloud has an average visual extinction of only 0.8 mag , which is close to the threshold for molecule formation .
With such an extinction threshold , molecular clouds in metal-poor regions should have high surface densities and high internal pressures .
If high pressure is associated with the formation of massive clusters , then metal-poor galaxies such as dwarfs in the early universe could have been the hosts of metal-poor globular clusters .