TY - JOUR
T1 - Spatially correlated cluster populations in the outer disk of ngc 3184
AU - Herbert-Fort, Stéphane
AU - Zaritsky, Dennis
AU - Moustakas, John
AU - Christlein, Daniel
AU - Wilcots, Eric
AU - Baruffolo, Andrea
AU - Dipaola, Andrea
AU - Fontana, Adriano
AU - Giallongo, Emanuele
AU - Pogge, Richard W.
AU - Ragazzoni, Roberto
AU - Smareglia, Riccardo
PY - 2009
Y1 - 2009
N2 - We use deep (27.5 mag V-band point-source limiting magnitude) V- and U-band Large Binocular Telescope imaging to study the outer disk (beyond the optical radius R 25) of the non-interacting, face-on spiral galaxy NGC 3184 (D = 11.1 Mpc; R 25 = 11.1 kpc) and find that this outer disk contains >1000 objects (or marginally resolved "knots") resembling star clusters with masses 102-104 M and ages up to 1Gyr. We find statistically significant numbers of these cluster-like knots extending to 1.4 R 25, with the redder knots outnumbering bluer at the largest radii. We measure clustering among knots and find significant correlation to galactocentric radii of 1.5 R 25 for knot separations <1 kpc. The effective integrated surface brightness of this outer disk cluster population ranges from 30-32 mag arcsec-2 in V. We compare the H I extent to that of the correlated knots and find that the clusters extend at least to the damped Lyman-α threshold of H I column density (2 × 1020 cm-2; 1.62 R 25). The blue knots are correlated with H I spiral structure to 1.5 R 25, while the red knots may be correlated with the outer fringes of the H I disk to 1.7 R 25. These results suggest that outer disks are well populated, common, and long-lasting features of many nearby disk galaxies.
AB - We use deep (27.5 mag V-band point-source limiting magnitude) V- and U-band Large Binocular Telescope imaging to study the outer disk (beyond the optical radius R 25) of the non-interacting, face-on spiral galaxy NGC 3184 (D = 11.1 Mpc; R 25 = 11.1 kpc) and find that this outer disk contains >1000 objects (or marginally resolved "knots") resembling star clusters with masses 102-104 M and ages up to 1Gyr. We find statistically significant numbers of these cluster-like knots extending to 1.4 R 25, with the redder knots outnumbering bluer at the largest radii. We measure clustering among knots and find significant correlation to galactocentric radii of 1.5 R 25 for knot separations <1 kpc. The effective integrated surface brightness of this outer disk cluster population ranges from 30-32 mag arcsec-2 in V. We compare the H I extent to that of the correlated knots and find that the clusters extend at least to the damped Lyman-α threshold of H I column density (2 × 1020 cm-2; 1.62 R 25). The blue knots are correlated with H I spiral structure to 1.5 R 25, while the red knots may be correlated with the outer fringes of the H I disk to 1.7 R 25. These results suggest that outer disks are well populated, common, and long-lasting features of many nearby disk galaxies.
KW - Galaxies: individual (NGC 3184)
KW - Galaxies: star clusters
KW - Galaxies: structure
KW - Methods: statistical
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U2 - 10.1088/0004-637X/700/2/1977
DO - 10.1088/0004-637X/700/2/1977
M3 - Article
AN - SCOPUS:70549108084
SN - 0004-637X
VL - 700
SP - 1977
EP - 1987
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
ER -