The 50 Mpc Galaxy Catalog (50MGC): Consistent and Homogeneous Masses, Distances, Colors, and Morphologies

TL;DR

This paper presents a comprehensive catalog of 15,424 nearby galaxies within 50 Mpc, providing homogenized measurements of mass, distance, morphology, and colors, enabling diverse studies of galaxy properties and activity.

Contribution

The creation of a large, consistent, and multi-faceted galaxy catalog combining data from multiple sources with new color-mass relations and an initial analysis of nuclear X-ray activity.

Findings

Early-type galaxies show higher X-ray active fractions than late-types.

X-ray activity correlates with galaxy stellar mass, especially between 10^9 and 10^10.5 M_sun.

Astrometric uncertainties affect activity detection in late-type galaxies.

Abstract

We assemble a catalog of 15424 nearby galaxies within 50 Mpc with consistent and homogenized mass, distance, and morphological type measurements. Our catalog combines galaxies from HyperLeda, the NASA-Sloan Atlas, and the Catalog of Local Volume Galaxies. Distances for the galaxies combine best-estimates for flow-corrected redshift-based distances with redshift independent distances. We also compile magnitude and color information for 11740 galaxies. We use the galaxy colors to estimate masses by creating self-consistent color -- mass-to-light ratio relations in four bands; we also provide color transformations of all colors into Sloan (g-i) by using galaxies with overlapping color information. We compile morphology information for 13744 galaxies, and use galaxy color information to separate early and late-type galaxies. This catalog is widely applicable for studies of nearby galaxies, and placing these studies in the context of more distant galaxies. We present one application here; a preliminary analysis of the nuclear X-ray activity of galaxies. Out of 1506 galaxies within the sample that have available Chandra X-ray observations, we find 291 have detected nuclear sources. Of the 291 existing Chandra detections, 249 have log(L$_{X}$)$>$38.3 and available stellar mass estimates. We find that the X-ray active fractions in early-type galaxies are higher than in late-type galaxies, especially for galaxy stellar masses between 10$^9$ and 10$^{10.5}$ M$_\odot$. We show that these differences may be due at least in part to the increased astrometric uncertainties in late-type galaxies relative to early-types.