HECATEv2 is a new, value-added list of nearby galaxies meant to help astronomers who study events like gravitational waves and high-energy flashes. It contains 204,733 galaxies drawn from the HyperLEDA database. All of the galaxies have recession velocities below 14,000 km/s, which corresponds to roughly 200 megaparsecs (about 650 million light years). The release focuses on providing more and better galaxy information across the whole sky.

The team kept the same parent galaxy sample as the first HECATE release but added several qualitative upgrades. They moved to a cosmology-based distance framework, so the listed distances are calculated consistently with modern cosmology. They also expanded and homogenised brightness measurements in visible light and mid-infrared light using data from SDSS-DR17/NSA, Pan-STARRS (PS1-DR2), and the AllWISE survey. New quality-control flags mark likely problems such as stars mistakenly counted as galaxies, bad photometry, or coordinate mismatches. The catalogue also covers a wider range of galaxy sizes.

HECATEv2 reports many derived galaxy properties for a much larger fraction of the sample than before. Star-formation rates (SFR) and stellar masses (Mstar) are available for more than 70% of the galaxies. These numbers come from updated calibrations that use both mid-infrared and optical light and that try to account for a galaxy’s stellar age and dust blocking light. Gas-phase metallicities — a measure of how rich a galaxy is in heavy elements — are given for about 90% of the sample. Activity classifications (for example, whether a galaxy hosts an active nucleus) are provided for over half of the galaxies, and estimates of supermassive black hole (SMBH) masses are available for about 86%.

This work matters because it gives researchers a broadly useful and fairly complete picture of the nearby galaxy population, at least in the properties listed here. In terms of blue-band and near-infrared luminosity, star-formation rate, and stellar mass, HECATEv2 is among the most complete local-Universe catalogues that have spectroscopic redshifts (direct speed measurements from spectra). Compared with other wide catalogues such as GLADE+ and NED-LVS, HECATEv2 provides broader coverage in optical and infrared photometry, metallicity, and activity classifications, and comparable coverage in mid-infrared photometry, SFR, and stellar mass. The authors also supply spatial completeness maps that show how the catalogue’s coverage changes with distance and brightness across the sky.