Journal article
SHIELD: COMPARING GAS AND STAR FORMATION IN LOW-MASS GALAXIES
The Astrophysical journal, Vol.832(1), p.85
11/20/2016
DOI: 10.3847/0004-637X/832/1/85
Abstract
ABSTRACT We analyze the relationships between atomic, neutral hydrogen (H i) and star formation (SF) in the 12 low-mass SHIELD galaxies. We compare high spectral (∼0.82 km s−1 ch−1) and spatial resolution (physical resolutions of 160-640 pc) H i imaging from the VLA with Hα and far-ultraviolet imaging. We quantify the degree of co-spatiality between star-forming regions and regions of high H i column densities. We calculate the global star formation efficiencies (SFE; / ) and examine the relationships among the SFE and H i mass, H i column density, and star formation rate (SFR). The systems are consuming their cold neutral gas on timescales of order a few gigayears. While we derive an index for the Kennicutt-Schmidt relation of N ≈ 0.68 ± 0.04 for the SHIELD sample as a whole, the values of N vary considerably from system to system. By supplementing SHIELD results with those from other surveys, we find that H i mass and UV-based SFR are strongly correlated over five orders of magnitude. Identification of patterns within the SHIELD sample allows us to bin the galaxies into three general categories: (1) mainly co-spatial H i and SF regions, found in systems with the highest peak H i column densities and highest total H i masses; (2) moderately correlated H i and SF regions, found in systems with moderate H i column densities; and (3) obvious offsets between H i and SF peaks, found in systems with the lowest total H i masses. SF in these galaxies is dominated by stochasticity and random fluctuations in their ISM.
Details
- Title: Subtitle
- SHIELD: COMPARING GAS AND STAR FORMATION IN LOW-MASS GALAXIES
- Creators
- Yaron G. Teich - Macalester CollegeAndrew T. McNichols - Macalester CollegeElise Nims - Macalester CollegeJohn M. Cannon - Macalester CollegeElizabeth A. K. Adams - Netherlands Institute for Radio AstronomyRiccardo Giovanelli - Planetary Science InstituteMartha P. Haynes - Planetary Science InstituteKristen B. W. McQuinn - University of MinnesotaJohn J. Salzer - Indiana University BloomingtonEvan D. Skillman - University of MinnesotaElijah Z. Bernstein-Cooper - Indiana University BloomingtonAndrew Dolphin - RTXE. C. Elson - University of Cape TownNathalie Haurberg - Knox CollegeGyula I. G. Józsa - University of BonnJürgen Ott - National Radio Astronomy ObservatoryAmelie Saintonge - University College LondonSteven R. Warren - CrayIan Cave - Macalester CollegeCedric Hagen - Macalester CollegeShan Huang - New York UniversitySteven Janowiecki - International Centre for Radio Astronomy ResearchMelissa V. Marshall - Macalester CollegeClara M. Thomann - Macalester CollegeAngela Van Sistine - University of Wisconsin–Milwaukee
- Resource Type
- Journal article
- Publication Details
- The Astrophysical journal, Vol.832(1), p.85
- Publisher
- The American Astronomical Society
- DOI
- 10.3847/0004-637X/832/1/85
- ISSN
- 0004-637X
- eISSN
- 1538-4357
- Number of pages
- 34
- Alternative title
- SHIELD: COMPARING GAS AND STAR FORMATION IN LOW-MASS GALAXIES
- Language
- English
- Date published
- 11/20/2016
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984627308002771
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