Visual morphological classification of the full MaNGA DR17 sample: a general characterization

TL;DR

We address the need for robust, large-scale morphological classifications in the local universe by delivering the MaNGA Visual Morphology (MVM) catalog for 10,059 DR17 galaxies, built from SDSS and DESI DESI images. Our approach combines detailed visual classifications (12 Hubble types), bar families, tidal features, and non-parametric CAS parameters, all cross-referenced with volume-corrected statistics and the MaNGA GSMF. The key contributions include the MVM-VAC data release, a bimodal morphology distribution with peaks at E/S0 and Scd, a 54% bar fraction in disc galaxies (i<70°) with bimodal morphology dependence, and a Treble-Schechter description of the total GSMF across morphologies, plus central/satellite trends in stellar populations. Collectively, these results provide a robust framework for studying galaxy evolution, secular processes, and training ML classifiers on deep, morphology-rich imaging, with implications for environment-driven transformation and galaxy assembly histories.

Abstract

We present the MaNGA Visual Morphology (MVM) catalogue, featuring a visual morphological classification of 10,059 galaxies in the final MaNGA sample. By combining SDSS and DESI Legacy Survey (DLS) images, we classified galaxies into 13 Hubble types, detected tidal features, categorized bars into different families, and estimated concentration, asymmetry, and clumpiness. The depth of the DLS images allowed us to identify structural details that were not evident in the SDSS images, resulting in a more reliable classification. After correcting for volume completeness, we find a bimodal distribution in galaxy morphology, with peaks in S0 and Scd types, and a transition zone around S0a-Sa types. Bars are present in 54% of disc galaxies with inclinations < 70, following a bimodal trend with peaks in Sab-Sb and Scd-Sd types. Tidal structures are identified in ~13% of galaxies, particularly in massive E-Sa and low-mass Sdm-Irr galaxies. We derive the galaxy stellar mass function (GSMF) and decompose it into each morphological type. Schechter functions accurately describe the latter, while a triple Schechter function describes the total GSMF, associating three characteristic masses with different galaxy types. The abundance of early-type galaxies remains constant at low masses; they are predominantly satellites. We confirm that later-type galaxies are generally younger, bluer, more star-forming, and less metal-rich compared to early-type galaxies. Additionally, we find evidence connecting morphology and stellar mass to the star formation history of galaxies. The MVM catalogue provides a robust dataset for investigating galaxy evolution, secular processes, and machine learning-based morphological classifications.

Figures (23)

• Figure 1: Poster-child of our classification scheme for early E, S0 and S0a types. For every mosaic, columns from left to right show the $gri$ SDSS image, the filtered-enhanced $r$-band DESI image, the $grz$ DESI image and the residual DESI image after a best 2D surface brightness model subtraction.
• Figure 2: Poster-child of our late type classification scheme from Sa to Sm. Mosaics are similar to those in Figure \ref{['fig:morpho_early']}.
• Figure 3: Bar family classification examples following the CVRHS system Buta2015. From left to right: (A) no-barred galaxy, ($\underline{A}$B) weak bar showing a roundish structure, (AB) bar in the inner region of the galaxy, (A$\underline{B}$) clear conspicuous bar, and (B) bar with high contrast with respect to other structures. Note that AB, A$\underline{B}$ and B families are strong bars. See more details in Sec. \ref{['Sec:BarClasificaion']}.
• Figure 4: Background replacement and homogeneization of images (see subsection \ref{['subsec:non-param morph']}) previous to $CAS$ estimates. Panels: original image, computed masks, background replacement and homogeneization.
• Figure 5: Morphology histogram showing the results of the classification carried out in this work. Every distribution represents the complete MaNGA sample (dotted-red line), the volume-corrected sample (solid-black line), the corresponding volume-corrected sample excluding galaxies with inclinations $> 70^\circ$ (dashed-black line), and the previous distribution presented in Paper I for the DR15 MaNGA sample (shadow gray area). Note that i) these distributions are normalized to the total number of galaxies in each sample, and ii) the volume-corrected distributions, only galaxies with $\log (\hbox{$M_{\ast}$}/M_{\sun})\geq$9.2 are considered. The vertical dotted line illustrates the separation between early and late type galaxies adopted in this work.