Gas Accretion by Globular Clusters and Nucleated Dwarf Galaxies and the Formation of the Arches and Quintuplet Clusters

We consider here the collective accretion of gas by globular clusters anddwarf galaxies moving through the interstellar medium. In the limit of highvelocity and/or sound speed of the ISM, the collective potential of the clusteris insufficient to accrete significant amounts of gas, and stars within thesystems accrete gas individually. We show, however, that when the sound speedor the relative velocity of the ambient medium is less than the centralvelocity dispersion of the cluster, it is accreted into the collectivepotential of the cluster prior to being accreted onto the individual starswithin the cluster. The collective rate is strongly enhanced relative to theindividual rates. This effect may potentially modify the white dwarf coolingsequence in globular clusters with low-inclination and low-eccentricityGalactic orbits, and lead to the rejuvenation of some marginally survivingcores of globular clusters and nucleated dwarf galaxies near the Galacticcenter. Such effects will only occur rarely, but may explain the existence ofclusters of young, massive stars near the Galactic center.Comment: 21 pages, 1 figure, to appear in The Astrophysical Journa