The gas morphology of nearby star-forming galaxies

doi:10.1051/0004-6361/202346318

機構典藏 > College of Sciences > Graduate Institute & Department of Physics > Journal Article > Item 987654321/124576

Please use this identifier to cite or link to this item: https://tkuir.lib.tku.edu.tw/dspace/handle/987654321/124576

Title:	The gas morphology of nearby star-forming galaxies
Authors:	Pan, Hsi-an
Keywords:	galaxies: structure;galaxies: spiral;galaxies: ISM
Date:	2023-08-17
Issue Date:	2023-10-04 12:05:53 (UTC+8)
Abstract:	A galaxy’s morphology stems from the secular and environmental processes taking place over the course of its evolutionary history. Thus, it has consistently served as an important tool for gaining insights into galaxy evolution. In this work, we visually classified morphologies on cloud-scales based on the molecular gas distribution of a large sample of 79 nearby main sequence galaxies, using 1″ resolution CO(2–1) ALMA observations taken as part of the PHANGS survey. For this purpose, we devised a morphology classification scheme for different types of bars, spiral arms (grand-design, flocculent, multi-arm and smooth), and rings (central and non-central rings) that are similar to the well established optical ones. Furthermore, we introduced bar lane classes. In general, our cold gas-based morphologies is in good agreement with the ones based on stellar light. Both of our bars, as well as the grand-design spiral arms, are preferentially found at the higher mass end of our sample. Our gas-based classification indicates a potential for a misidentification of unbarred galaxies in the optical when massive star formation is present. Central or nuclear rings are present in a third of the sample, with a strong preference seen for barred galaxies (59%). As stellar bars are present in 45 ± 5% of our sample galaxies, we explore the utility of molecular gas as tracer of bar lane properties. We find that more curved bar lanes have a shorter radial extent in molecular gas and reside in galaxies with lower molecular to stellar mass ratios than those with straighter geometries. Galaxies display a wide range of CO morphologies and this work is aimed at providing a catalogue of morphological features in a representative sample of nearby galaxies.
Relation:	Astronomy & Astrophysics 676,　A113
DOI:	10.1051/0004-6361/202346318
Appears in Collections:	[Graduate Institute & Department of Physics] Journal Article

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