2002AJ....124.3144P -
Astron. J., 124, 3144-3156 (2002/December-0)
A young blue tidal stream in NGC 5128.
PENG E.W., FORD H.C., FREEMAN K.C. and WHITE R.L.
Abstract (from CDS):
Stellar streams in galaxy halos are the natural consequence of a history of merging and accretion. We present evidence for a blue tidal stream of young stars in the nearest giant elliptical galaxy, NGC 5128 (Centaurus A). Using optical UBVR color maps, unsharp masking, and adaptive histogram equalization, we detect a blue arc in the northwest portion of the galaxy that traces a partial ellipse with an apocenter of 8 kpc. We also report the discovery of numerous young star clusters that are associated with the arc. The brightest of these clusters is spectroscopically confirmed, has an age of ∼350 Myr, and may be a proto-globular cluster. It is likely that this arc, which is distinct from the surrounding shell system and the young jet-related stars in the northeast, is a tidally disrupted stellar stream orbiting the galaxy. Both the age derived from the integrated optical colors of the stream and its dynamical disruption timescale have values of 200-400 Myr. We propose that this stream of young stars was formed when a dwarf irregular galaxy, or similar-sized gas fragment, underwent a tidally triggered burst of star formation as it fell into NGC 5128 and was disrupted ∼300 Myr ago. The stars and star clusters in this stream will eventually disperse and become part of the main body of NGC 5128, suggesting that the infall of gas-rich dwarfs plays a role in the building of stellar halos and globular cluster systems.
Abstract Copyright:
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Journal keyword(s):
Galaxies: Dwarf - Galaxies: Elliptical and Lenticular, cD - Galaxies: Halos - Galaxies: Individual: NGC Number: NGC 5128 - Galaxies: Interactions - Galaxies: Star Clusters - Galaxies: Stellar Content
Simbad objects:
11
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