Star formation outside the Elliptical Galaxy NGC2865

Abstract

We have searched for young stellar complexes around the elliptical galaxy NGC2865. We find them in a ring of HI around the galaxy. Using the Multi-Slit Imaging Spectroscopy Technique (MSIS), we detected a total of seven Hα emitters in the south part of the tidal tail of the galaxy NGC2865. These regions are young sources with stellar masses in the range 4×10^{3}M_{odot} to 2×10^{6}M_{odot}, overlapping the location of the low density intergalactic HI gas, where the probability to form stars is expected to be low. For one of the intergalactic HII regions we estimated a solar oxygen abundance, 12 + log(O/H) ∼ 8.7. Given these proprieties, the regions are considered young star forming regions, born in-situ from a pre-enriched gas which has been removed from the host galaxies in a merger event.