Giant H II regions in the merging system NGC 3256: Are they the birthplaces of globular clusters?

Abstract

CCD images and spectra of ionized hydrogen in the merging system NGC3256 were acquired as part of a kinematic study to investigate the formation of globular clusters (GC) during the interactions and mergers of disk galaxies. This paper focuses on the proposition that giant H II regions, with an H_alpha luminosity > 1.5 x 10^{40} erg s^{-1}, are birthplaces of young populous clusters (YPC). We estimate 900 30-Doradus-like H II regions formed during the galaxy-galaxy interaction which created NGC 3256. A specific frequency argument for forming a sufficient number of GC, assuming that the NGC3256 merger remnant will be an elliptical galaxy, only requires that about 10% of these H II regions harbor YPC which survive several Gyr and have masses at least as large as the cluster R136 in 30 Doradus.