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Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Astrophysics and Astronomy

Florida Institute of Technology

Series

2014

Galaxies: Spiral

Articles 1 - 2 of 2

Full-Text Articles in Physical Sciences and Mathematics

Unveiling The Structure Of Barred Galaxies At 3.6 Μm With The Spitzer Survey Of Stellar Structure In Galaxies (S4g). I. Disk Breaks, Taehyun Kim, Trisha Mizusawa Feb 2014

Unveiling The Structure Of Barred Galaxies At 3.6 Μm With The Spitzer Survey Of Stellar Structure In Galaxies (S4g). I. Disk Breaks, Taehyun Kim, Trisha Mizusawa

Aerospace, Physics, and Space Science Faculty Publications

We have performed two-dimensional multicomponent decomposition of 144 local barred spiral galaxies using 3.6 μm images from the Spitzer Survey of Stellar Structure in Galaxies. Our model fit includes up to four components (bulge, disk, bar, and a point source) and, most importantly, takes into account disk breaks. We find that ignoring the disk break and using a single disk scale length in the model fit for Type II (down-bending) disk galaxies can lead to differences of 40% in the disk scale length, 10% in bulge-to-total luminosity ratio (B/T), and 25% in bar-to-total luminosity ratios. We find that for galaxies …


Embedded Star Formation In S4g Galaxy Dust Lanes, Debra M. Elmegreen, Trisha Mizusawa Jan 2014

Embedded Star Formation In S4g Galaxy Dust Lanes, Debra M. Elmegreen, Trisha Mizusawa

Aerospace, Physics, and Space Science Faculty Publications

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 ∼10 7 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 …