S. Torres-Flores, C. Mendes de Oliveira, D. F. de Mello, S. Scarano Jr, F. Urrutia-Viscarra
We have searched for young star-forming regions around the merger remnant NGC
2782. By using GALEX FUV and NUV imaging and HI data we found seven UV sources,
located at distances greater than 26 kpc from the center of NGC 2782, and
coinciding with its western HI tidal tail. These regions were resolved in
several smaller systems when Gemini/GMOS r-band images were used. We compared
the observed colors to stellar population synthesis models and we found that
these objects have ages of ~1 to 11 Myr and masses ranging from 10^3.9 to
10^4.6 Msun. By using Gemini/GMOS spectroscopic data we confirm memberships and
derive high metallicities for three of the young regions in the tail
(12+log(O/H)=8.74\pm0.20, 8.81\pm0.20 and 8.78\pm0.20). These metallicities are
similar to the value presented by the nuclear region of NGC 2782 and also
similar to the value presented for an object located close to the main body of
NGC 2782. The high metallicities measured for the star-forming regions in the
gaseous tidal tail of NGC 2782 could be explained if they were formed out of
highly enriched gas which was once expelled from the center of the merging
galaxies when the system collided. An additional possibility is that the tail
has been a nursery of a few generations of young stellar systems which
ultimately polluted this medium with metals, further enriching the already
pre-enriched gas ejected to the tail when the galaxies collided.
View original:
http://arxiv.org/abs/1201.3927
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