GALEX observations of Low Surface Brightness Galaxies: UV color and star formation efficiency - AstrophysicsReportar como inadecuado




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Abstract: We present GALEX UV observations of a sample of Low Surface Brightness LSBgalaxies for which HI data are available, allowing us to estimate their starformation efficiency. We find that the UV light extends to larger radii thanthe optical light some galaxies, but not all, look similar to the recentlydiscovered XUV-disk galaxies. Using a standard calibration to convert the UVlight into star formation rates, we obtain lower star formation efficiencies inLSB galaxies than in high surface brightness galaxies by about one order ofmagnitude.We show however that standard calibrations may not apply to these galaxies,as the FUV-NUV color obtained from the two GALEX bands FUV and NUV;lambda eff= 1516 and 2267 A, respectively is redder than expected for starforming galaxies. This color can be interpreted as a result of internalextinction, modified Initial Mass Function or by star formation historiescharacterized by bursts followed by quiescent phases. Our analysis favors thislatter hypothesis.



Autor: S. Boissier, A. Gil de Paz, A. Boselli, V. Buat, B. Madore, L. Chemin, C. Balkowski, P. Amram, C. Carignan, W. van Driel

Fuente: https://arxiv.org/







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