Morphologies of SAGAbg low-mass galaxies in Legacy Survey multi-band imaging: dependence on stellar masses, star-formation rates and low-redshift evolution

arXiv:2607.16170 · astro-ph.GA · Submitted 2026-07-17 · Read on arXiv

Joy Bhattacharyya, Guinevere Herron, Yasmeen Asali, Abby Mintz, Mithi A. C. de los Reyes, Yao-Yuan Mao, Annika H. G. Peter

astro-ph.GA

Submitted: 2026-07-17

Comments: 24 pages, 16 figures. Submitted to ApJ

License: http://creativecommons.org/licenses/by/4.0/

The gist: The optical morphologies of low-mass galaxies can be used to directly trace their assembly and constrain models of galaxy evolution.

Terminology

Trace — 7× in this paper · explained in 2 episodes
Aperture — 5× in this paper · explained in 1 episode
Dark Energy Survey — 4× in this paper
Kernel Density Estimate — 4× in this paper
Metallicity — 4× in this paper · explained in 3 episodes
Robustness — 3× in this paper · explained in 5 episodes
Clustering — 2× in this paper · explained in 2 episodes
Embeddings — 2× in this paper · explained in 2 episodes
Satellites Around Galactic Analogs — 2× in this paper
Symbolic Regression — 2× in this paper · explained in 5 episodes
AGN — 1× in this paper · explained in 1 episode
AGN Feedback — 1× in this paper · explained in 1 episode
Abundance — 1× in this paper · explained in 1 episode
Aperture Photometry — 1× in this paper · explained in 1 episode
Beijing-Arizona Sky Survey — 1× in this paper
Cooperation — 1× in this paper · explained in 2 episodes
Core — 1× in this paper · explained in 2 episodes
DESI Legacy Survey — 1× in this paper
Dark Energy Spectroscopic Instrument — 1× in this paper
Distribution Shift — 1× in this paper · explained in 5 episodes
Dust Attenuation — 1× in this paper · explained in 2 episodes
Galaxy And Mass Assembly — 1× in this paper
Homogeneity — 1× in this paper · explained in 2 episodes
Legacy Survey of Space and Time — 1× in this paper
NOIRLab and the Lawrence Berkeley National Laboratory — 1× in this paper
Near-Earth Object Wide-field Infrared Survey Explorer — 1× in this paper
Principal Component Analysis (PCA) — 1× in this paper · explained in 4 episodes
Sloan Digital Sky Survey — 1× in this paper

Abstract

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 log (M/M) 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, M 20 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-M 20 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 M 20 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 (log (M/M) 9).

Morphologies of SAGAbg low-mass galaxies in Legacy Survey multi-band imaging: dependence on stellar masses, star-formation rates and low-redshift evolution

Terminology

Abstract

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