We use ALMA to detect and image CO ( 1-0 ) emission from Minkowski ’ s Object , a dwarf galaxy that is interacting with a radio jet from a nearby elliptical galaxy .
These observations are the first to detect molecular gas in Minkowski ’ s Object .
We estimate the range in the mass of molecular gas in Minkowski ’ s Object assuming two different values of the ratio of the molecular gas mass to the CO luminosity , \alpha _ { CO } .
For the Milky Way value of \alpha _ { CO } = 4.6 ~ { } M _ { \odot } { ( K~ { } km~ { } s ^ { -1 } ~ { } pc ^ { 2 } ) ^ { -1 } } we obtain a molecular gas mass of M _ { H _ { 2 } } = 3.0 \times 10 ^ { 7 } ~ { } M _ { \odot } , 6 % of the H I gas mass .
We also use the prescription of Narayanan et al .
( 2012 ) to estimate an \alpha _ { CO } = 27 ~ { } M _ { \odot } { ( K~ { } km~ { } s ^ { -1 } ~ { } pc ^ { 2 } ) ^ { -1 } } , in which case we obtain M _ { H _ { 2 } } = 1.8 \times 10 ^ { 8 } ~ { } M _ { \odot } , 36 % of the H I mass .
The observations are consistent with previous claims of star formation being induced in Minkowski ’ s Object via the passage of the radio jet , and it therefore being a rare local example of positive feedback from an AGN .
In particular , we find highly efficient star formation , with gas depletion timescales \sim 5 \times 10 ^ { 7 } -3 \times 10 ^ { 8 } yr ( for assumed values of \alpha _ { CO } = 4.6 and 27 ~ { } M _ { \odot } { ( K~ { } km~ { } s ^ { -1 } ~ { } pc ^ { 2 } ) ^ { -1 } } , respectively ) in the upstream regions of Minkowski ’ s Object that were struck first by the jet , and less efficient star formation downstream .
We discuss the implications of this observation for models of jet induced star formation and radio mode feedback in massive galaxies .