2016ApJ...818..142D -
Astrophys. J., 818, 142 (2016/February-3)
The compact star-forming complex at the heart of NGC 253.
DAVIDGE T.J.
Abstract (from CDS):
We discuss integral field spectra of the compact star-forming complex that is the brightest near-infrared (NIR) source in the central regions of the starburst galaxy NGC 253. The spectra cover the H and K passbands and were recorded with the Gemini NIR Spectrograph during subarcsecond seeing conditions. Absorption features in the spectrum of the star-forming complex are weaker than in the surroundings. An absorption feature is found near 1.78 µm that coincides with the location of a C2bandhead. If this feature is due to C2 then the star-forming complex has been in place for at least a few hundred Myr. Emission lines of Brγ, [Fe ii], and He i 2.06 µm do not track the NIR continuum light. Pockets of star-forming activity that do not have associated concentrations of red supergiants, and so likely have ages <8 Myr, are found along the western edge of the complex, and there is evidence that one such pocket contains a rich population of Wolf-Rayet stars. Unless the star-forming complex is significantly more metal-poor than the surroundings, then a significant fraction of its total mass is in stars with ages <8 Myr. If the present-day star formation rate is maintained then the timescale to double its stellar mass ranges from a few Myr to a few tens of Myr, depending on the contribution made by stars older than ∼8 Myr. If–as suggested by some studies–the star-forming complex is centered on the galaxy's nucleus, which presumably contains a large population of old and intermediate-age stars, then the nucleus of NGC 253 is currently experiencing a phase of rapid growth in its stellar mass.
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Journal keyword(s):
galaxies: individual: NGC 253 - galaxies: spiral - galaxies: starburst
Simbad objects:
14
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