摘要：Context.The morphological evolution of star-forming galaxies provides important clues to understand their physical properties, as well as the triggering and quenching mechanisms of star formation.Aims.We analyze the morphology of galaxies hosting star-forming events at low redshift (z < 0.36). We aim at connecting morphology and star-formation properties of low-mass galaxies (median stellar mass ∼108.5 M⊙) beyond the local Universe.Methods.We use a sample of mediumband selected star-forming galaxies from the GOODS-North field. Hαimages for the sample are created combining both spectral energy distribution fits and HST data. Using them, we mask the star forming regions to obtain an unbiased two-dimensional model of the light distribution of the host galaxies. For this purpose we usePHI, a new Bayesian photometric decomposition code. We applied it independently to 7 HST bands, from the ultraviolet to the near-infrared, assuming a Sérsic surface brightness model.Results.Star-forming galaxy hosts show low Sérsic index (with mediann ∼ 0.9), as well as small sizes (medianRe ∼ 1.6 kpc), and negligible change of the parameters with wavelength (except for the axis ratio, which grows with wavelength in 46% of the sample). Using a clustering algorithm, we find two different classes of star-forming galaxies: A more compact, redder, and high-n(class A) and a more extended, bluer and lower-none (class B). This separation holds across all seven bands analyzed. In addition, we find evidence that the first class is more spheroidal-like (according to the distribution of observed axis ratios). We compute the color gradients of the host galaxies finding that 48% of the objects where the analysis could be performed show negative gradients, and only in 5% they are positive.Conclusions.The host component of low-mass star-forming galaxies atz < 0.36 separates into two different classes, similar to what has been found for their higher mass counterparts. The results are consistent with an evolution from class B to class A. Several mechanisms from the literature, like minor and major mergers, and violent disk instability, can explain the physical process behind the likely transition between the classes.
关键词：engalaxies: star formationgalaxies: photometrygalaxies: structuregalaxies: evolutiongalaxies: starburstgalaxies: fundamental parameters
