THE STRUCTURE AND METALLICITY GRADIENT IN THE EXTREME OUTER DISK OF NGC 7793

Journal Article · Sun May 01 04:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/732/1/7· OSTI ID:21574669

Vlajic, M ^[1]; Bland-Hawthorn, J ^[2]

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1. Astrophysikalisches Institut Potsdam, An der Sterwarte 16, D-14482 Potsdam (Germany)
2. Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia)

Studies of outer regions of spirals disks are fundamental to our understanding of both the process of galaxy assembly and the subsequent secular evolution of galaxies. In an earlier series of papers, we explored the extent and abundance gradient in the outer disk of NGC 300 and found an extended purely exponential disk with a metallicity gradient which flattens off in the outermost regions. We now continue the study of outskirts of pure disk spirals with another Sculptor Group spiral, NGC 7793. Using the Gemini Multi Object Spectrograph camera at Gemini South, we trace the disk of NGC 7793 with star counts out to {approx}9 scale lengths, corresponding to 11.5 kpc at our calibrated distance of 3.61 {+-} 0.53 Mpc. The outer disk of NGC 7793 shows no evidence of a break in its light profile down to an effective surface brightness of {approx}30 mag arcsec{sup -2} ({approx}3 mag arcsec{sup -2} deeper than what has been achieved with surface photometry) and exhibits a non-negative abundance gradient within the radial extent of our data.

• OSTI ID: 21574669
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 732; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABUNDANCE
EVOLUTION
GALACTIC EVOLUTION
GALAXIES
STARS