Mass Distribution in Stellar Structures of Local Dwarfs. Issue Volume 14:Issue S344(2019) (August 2018)

• Record Type: Journal Article
• Authors: Menéndez-Delmestre, Karín; Coelho, Yasmin; Grossi, Marco; Sheth, Kartik
• Editors: McQuinn, Kristen B. W.; Stierwalt, Sabrina
• Is Part Of: Proceedings of the International Astronomical Union. Volume 14:Issue S344(2019)
• Page Start: 340
• Page End: 344
• Publication Date: 2018-08
• Subjects: galaxies: dwarf, -- galaxies: structure, -- infrared: galaxies; Astronomy -- Congresses; Astronomy -- Periodicals; 520
• DOI: 10.1017/S1743921318008098
• Languages: English
• ISSNs: 1743-9213

Abstract

Abstract: We study the distribution of mid-infrared light in stellar structures in a large sample (∽ 400) of low-mass (M stellar <10 9 M Sun ) galaxies. Our sample is selected from the Spitzer Survey of Stellar Structures in Galaxies (S4G), which entails deep imaging of nearby galaxies with the IRAC instrument at 3.6/4.5 μ m. Based on the 2D decomposition of the 3.6 μ m images, we find that the majority (∽65%) of galaxies in our sample is well-fit by a single disk profile. The rest of the sample is more adequately fit by a disk and an additional component (e.g., bar, nucleus, bulge, second disk component). Bars are present in ∽11% of the sample, marking a sharp drop in the bar fraction compared to that found for more massive galaxies. The typical contribution of bars to the 3.6 μ m light in dwarfs is ∽1-2%, lower than that found in more massive galaxies. These results bring a number of issues into question: why do low-mass galaxies have such low bar fraction? does the bar instability act differently in low-mass galaxies such that a smaller proportion of stellar mass is typically involved in the bar structure? Is the fact that dwarfs are more dark matter dominated playing a role?