Embedded Star Formation in S4G Galaxy Dust Lanes

Mizusawa, Trisha; Menéndez-Delmestre, Karín; Laurikainen, Eija; Laine, Jarkko; Kim, Taehyun; Holwerda, Benne; Ho, Luis C.; Hinz, Joannah L.; Gil de Paz, Armando; Gadotti, Dimitri A.; Efremov, Yuri N.; Comerón, Sébastien; Bosma, Albert; Athanassoula, E.; Popinchalk, Mark; Teich, Yaron; Knapen, J. H.; Erroz-Ferrer, S.; Elmegreen, Bruce G.; Elmegreen, D. M.; Muñoz-Mateos, Juan-Carlos; Sheth, Kartik; Seibert, Mark; Salo, Heikki; Regan, Michael W.
Bibliographical reference

The Astrophysical Journal, Volume 780, Issue 1, article id. 32, 12 pp. (2014).

Advertised on:
1
2014
Number of authors
25
IAC number of authors
2
Citations
17
Refereed citations
17
Description
Star-forming regions that are visible at 3.6 μm and Hα but not in the u, g, r, i, z bands of the Sloan Digital Sky Survey are measured in five nearby spiral galaxies to find extinctions averaging ~3.8 mag and stellar masses averaging ~5 × 104 M ☉. These regions are apparently young star complexes embedded in dark filamentary shock fronts connected with spiral arms. The associated cloud masses are ~107 M ☉. The conditions required to make such complexes are explored, including gravitational instabilities in spiral-shocked gas and compression of incident clouds. We find that instabilities are too slow for a complete collapse of the observed spiral filaments, but they could lead to star formation in the denser parts. Compression of incident clouds can produce a faster collapse but has difficulty explaining the semi-regular spacing of some regions along the arms. If gravitational instabilities are involved, then the condensations have the local Jeans mass. Also in this case, the near-simultaneous appearance of equally spaced complexes suggests that the dust lanes, and perhaps the arms too, are relatively young.
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