Accumulating observational evidence for a number of radio galaxies suggests an association between their jets and regions of active star formation .
The standard picture is that shocks generated by the jet propagate through an inhomogeneous medium and trigger the collapse of overdense clouds , which then become active star-forming regions .
In this contribution , we report on recent hydrodynamic simulations of radiative shock-cloud interactions using two different cooling models : an equilibrium cooling-curve model assuming solar metallicities and a non-equilibrium chemistry model appropriate for primordial gas clouds .
We consider a range of initial cloud densities and shock speeds in order to quantify the role of cooling in the evolution .
Our results indicate that for moderate cloud densities ( \gtrsim 1 cm ^ { -3 } ) and shock Mach numbers ( \lesssim 20 ) , cooling processes can be highly efficient and result in more than 50 % of the initial cloud mass cooling to below 100 K. We also use our results to estimate the final H _ { 2 } mass fraction for the simulations that use the non-equilibrium chemistry package .
This is an important measurement , since H _ { 2 } is the dominant coolant for a primordial gas cloud .
We find peak H _ { 2 } mass fractions of \gtrsim 10 ^ { -2 } and total H _ { 2 } mass fractions of \gtrsim 10 ^ { -5 } for the cloud gas , consistent with cosmological simulations of first star formation .
Finally , we compare our results with the observations of jet-induced star formation in “ Minkowski ’ s Object , ” a small irregular starburst system associated with a radio jet in the nearby cluster of galaxies Abell 194 .
We conclude that its morphology , star formation rate ( \sim 0.3 M _ { \odot } yr ^ { -1 } ) and stellar mass ( \sim 1.2 \times 10 ^ { 7 } M _ { \odot } ) can be explained by the interaction of a \sim 9 \times 10 ^ { 4 } km s ^ { -1 } jet with an ensemble of moderately dense ( \sim 10 cm ^ { -3 } ) , warm ( 10 ^ { 4 } K ) intergalactic clouds in the vicinity of its associated radio galaxy at the center of the galaxy cluster .