Duilia de Mello, Claudia Mendes de Oliveira, Sergio Torres-Flores, and Fernanda Urrutia-Viscarra
Young Galaxies and Stellar
Nurseries Born when
Galaxies Collide
Gemini Multi-Object Spectrograph observations lead to a better
understanding of how tidal tails of galaxy mergers may not only pollute their
intergalactic environment but also form young galaxies and stellar nurseries
when galaxies collide.
When galaxies collide they go through dramatic transformations leaving behind debris in the
intergalactic medium. In the past few years we’ve developed a method using multi-wavelength
data that has proven quite successful in identifying newly formed objects within this tidal debris.
First, we searched the literature for cases of interacting galaxies with extended neutral hydrogen
(HI) tidal tails. We then used a source-finder algorithm on ultraviolet (UV) images taken with the
Galaxy Evolution Explorer Satellite (GALEX) to identify sources that coincided with the HI tails.
To date, we’ve detected 263 such UV objects in 33 interacting systems. In all cases, these UV
sources lie outside large galaxies and may be associated with debris of previous galaxy collisions.
Our next main goal was to establish the physical properties of these UV sources; all belong to
low-density environments where the physical processes might differ from those in star-forming
regions in disks of spiral galaxies. However, GALEX data alone could not provide enough information and multi-wavelength data, in particular spectroscopy, to verify their nature and whether
these sources are part of the interacting system.
December2012
GeminiFocus
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