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Paper: Gas and Star Formation in Extremely Faint Dwarf Galaxies
Volume: 407, The Low-Frequency Radio Universe
Page: 106
Authors: Roychowdhury, S.; Chengalur, J.N.; Begum, A.; Karachentsev, I.D.
Abstract: We study the relationship between the gas column density (gas) and the star formation rate surface density ( SFR) for a sample of extremely faint dwarf irregular galaxies. All galaxies were observed at ~400 pc linear resolution in two wavebands, viz. HΙ and FUV. ΣSFR is derived from GALEX data, while Σgas is derived from the GMRT based FIGGS HΙ 21 cm survey data. We find that Σgas averaged over the star forming region of the disk lies below most estimates of the “threshold density” for star formation, and that the average ΣSFR is also lower than would be expected from the “Kennicutt−Schmidt” law (Kennicutt, 1998a). We also use our data to look for small scale (400 pc and 200 pc) correlations between ΣSFR and Σgas. For 18 of our 23 galaxies, we find that SFR can be parametrized as having a power law dependence on gas. The power law relation holds until one reaches the sensitivity limit of the GALEX data, i.e. we find no evidence for a “threshold density” below which star formation is completely cut off.
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