Bibcode
Gouliermis, D. A.; Thilker, David; Elmegreen, Bruce G.; Elmegreen, Debra M.; Calzetti, Daniela; Lee, Janice C.; Adamo, Angela; Aloisi, Alessandra; Cignoni, Michele; Cook, David O.; Dale, Daniel A.; Gallagher, John S.; Grasha, Kathryn; Grebel, Eva K.; Herrero, A.; Hunter, Deidre A.; Johnson, Kelsey E.; Kim, Hwihyun; Nair, Preethi; Nota, Antonella; Pellerin, Anne; Ryon, Jenna; Sabbi, Elena; Sacchi, Elena; Smith, Linda J.; Tosi, Monica; Ubeda, Leonardo; Whitmore, Brad
Referencia bibliográfica
Monthly Notices of the Royal Astronomical Society, Volume 452, Issue 4, p.3508-3528
Fecha de publicación:
10
2015
Número de citas
38
Número de citas referidas
34
Descripción
We present a detailed clustering analysis of the young stellar
population across the star-forming ring galaxy NGC 6503, based on the
deep Hubble Space Telescope photometry obtained with the Legacy
ExtraGalactic UV Survey. We apply a contour-based map analysis technique
and identify in the stellar surface density map 244 distinct
star-forming structures at various levels of significance. These stellar
complexes are found to be organized in a hierarchical fashion with 95
per cent being members of three dominant super-structures located along
the star-forming ring. The size distribution of the identified
structures and the correlation between their radii and numbers of
stellar members show power-law behaviours, as expected from scale-free
processes. The self-similar distribution of young stars is further
quantified from their autocorrelation function, with a fractal dimension
of ˜1.7 for length-scales between ˜20 pc and 2.5 kpc. The
young stellar radial distribution sets the extent of the star-forming
ring at radial distances between 1 and 2.5 kpc. About 60 per cent of the
young stars belong to the detected stellar structures, while the
remaining stars are distributed among the complexes, still inside the
ring of the galaxy. The analysis of the time-dependent clustering of
young populations shows a significant change from a more clustered to a
more distributed behaviour in a time-scale of ˜60 Myr. The
observed hierarchy in stellar clustering is consistent with star
formation being regulated by turbulence across the ring. The rotational
velocity difference between the edges of the ring suggests shear as the
driving mechanism for this process. Our findings reveal the interesting
case of an inner ring forming stars in a hierarchical fashion.