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Accession Number
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N20120010114
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Title
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NGC 2782: A Merger Remnant with Young Stars in its Gaseous Tidal Tail.
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Publication Date
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2012
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Media Count
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11p
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Personal Author
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C. M. De Oliveira D. F. De Mello R. Urrutia-Viscarra S. Scarano S. Torres-Flores
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Abstract
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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 NGG 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 approximately l to 11 Myr and masses ranging from 10(exp 3.9) to l0(exp 4.6) Solar Mass. 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+/-0.20, 8.81+/-0.20 and 8.78+/-0.20). These metallicities are similar to the value presented by the nuclear region of NGG 2782 and also similar to the value presented for an object located close to the main body of NGG 2782. The high metallicities measured for the star-forming regions in the gaseous tidal tail of NGG 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.
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Keywords
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Galaxies
Interacting galaxies
Intergalactic media
Metallicity
Spectroscopy
Star clusters
Star formation
Star formation rate
Stellar evolution
Stellar models
Stellar systems
Ultraviolet spectrometers
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Source Agency
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National Aeronautics and Space Administration
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NTIS Subject Category
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54C - Astrophysics
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Corporate Author
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Goddard Space Flight Center, Greenbelt, MD.
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Document Type
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Journal article
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Title Note
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N/A
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NTIS Issue Number
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1226
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Contract Number
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FONDECYT 3110087 FAPESP 2007/07973-3
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