2026/07/17 by Joy Bhattacharyya, Guinevere Herron, Yasmeen Asali +4
#astro-ph.GA
The optical morphologies of low-mass galaxies can be used to directly trace their assembly and constrain models of galaxy evolution. We select a sample of 6211 low-mass (7\lesssim \rm log(M∗/M\odot)\lesssim 10) star-forming galaxies from the SAGAbg catalog that has high-completeness at low-redshifts (z<0.1). We obtain their galaxy maps in the griz - bands of the Legacy Surveys and apply STATMORPH to calculate non-parametric morphological measures including the Gini index, M20 measure, and CAS parameters. We study how resolution and signal-to-noise affect the morphology measures and find that the bulge strength measurements are the most reliable. The sequence in Gini-M20 space is directly linked to the star-forming sequence of galaxies and is dominated by Sb/Sc/Ir morphologies. The g-band light distributions are the least concentrated among all the bands. The systematic trends of M20 with respect to stellar mass and GALEX NUV-derived specific star formation rate (sSFR) strongly indicate that the galaxies with flatter light profiles are less massive with higher sSFR and vice-versa. We statistically infer that star-forming low-mass galaxies predominantly have disk morphologies with bulges becoming more prominent in quenched systems at higher masses (\rm log(M∗/M\odot)\gtrsim 9).