Artículos de revistas
Star-forming regions and the metallicity gradients in the tidal tails: the case of NGC 92
Fecha
2014Registro en:
Monthly Notices of the Royal Astronomical Society, Oxford, v. 438, p. 1894-1908, 2014
0035-8711
10.1093/mnras/stt2340
Autor
Torres-Flores, S.
Scarano Jr., S.
Oliveira, Claudia Lucia Mendes de
Mello, D. F. de
Amram, P.
Plana, H.
Institución
Resumen
We present new Gemini/GMOS spectroscopic and archival imaging data of the interacting
galaxy NGC 92, which is part of a compact group and displays an extended tidal tail.We have
studied the physical properties of 20 star-forming complexes in this system. We found that
the star-forming regions located in the tidal tail of NGC 92 have ages younger than ∼8Myr,
which suggests that these objects were formed in situ. The spectroscopic data reveal that
these regions have slightly sub-solar metallicities, suggesting that they were formed from
pre-enriched material. Using the oxygen abundances derived for each system, we found that
the extended tidal tail of NGC 92 has a flat metallicity distribution. Although this scenario is
consistent with N-body simulations of interacting systems, where there is gas mixing triggered
by the interaction, archival Hα Fabry–Perot data cubes of NGC 92 have not shown a velocity
gradient along the tail of this galaxy, which under certain assumptions could be interpreted
as a lack of gas flow in the tail. Our results suggest that a fraction of the enriched gas that
was originally located in the centre of the galaxy was expelled into the tidal tail when the
interacting process that formed the tail happened. However, we cannot exclude the scenario in
which the star formation in the tail has increased its original oxygen abundance