DRAFT
2026-05-07 16:30:23
Type: Announcement-Data Release
Bibcode: 2026TNSAN.128....1C
Updated Version of NED-LVS Galaxies (April 2026)
Authors: David Cook (Caltech/IPAC), Joseph Mazzarella (Caltech/IPAC), George Helou (Caltech/IPAC), Alexis Alcala (Caltech/IPAC), Ben Chan (Caltech/IPAC), Rick Ebert (Caltech/IPAC), Cren Frayer (Caltech/IPAC), Joyce Kim (Caltech/IPAC), Tak Lo (Caltech/IPAC), Marion Schmitz (Caltech/IPAC), Shin-Ywan Wang (Caltech/IPAC), Xiuqin Wu (Caltech/IPAC)
Keywords: Catalogs, Astronomical Databases, Galaxy, Gravitational Waves
Abstract:
We announce an update to the NASA/IPAC Extragalactic Database Local Volume sample (NED-LVS). The April 2026 version of NED-LVS has the same composition as that of the June 2025 version, but now has galaxy angular diameters. Observed angular sizes, or diameters, are fundamental measurements of galaxies that provide a means to understand galaxy evolution, and can be critical in Time Domain and Multi-Messenger (TDAMM) astronomy to help identify the hosts of transient events.

The NED Local Volume Sample (NED-LVS; Cook et al. 2023) is a subset of NED that contains over 2 million objects with distances out to 1000 Mpc. The distances selected for NED-LVS are based on both redshifts (~99%) and redshift-independent distances integrated from the literature and large surveys. The data in NED are updated regularly, and new versions of NED-LVS are extracted periodically. Consequently, NED-LVS will continue to provide an increasingly complete sample of galaxies for a multitude of astrophysical research areas (star formation, galaxy evolution, large scale structure, galaxy environments, and searches for the electromagnetic counterparts to gravitational wave events) for years to come. For more information and to download the latest version go to https://ned.ipac.caltech.edu/NED::LVS/  

NED-LVS is utilized by the NED Gravitational Wave Follow-up (NED-GWF) service, which provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert issued by the International Gravitational Wave Network (IGWN), these products are automatically generated and made available within minutes to expedite efficient electromagnetic follow-up observations. The galaxy lists produced by NED-GWF also provide several pre-computed prioritization metrics (i.e., stellar mass, star formation rate, and specific star formation rate, etc.), which are available by downloading the entire galaxy list inside an event's probability volume. For more information on NED-GWF and the API, go to https://ned.ipac.caltech.edu/NED::GWFoverview/.

Since no current survey provides uniform sizes for all NED-LVS galaxies, the new diameters were constructed by combining measurements across different surveys, diameter definitions, and filters into a fiducial quantity that represents statistically similar values. The new fiducial diameters in NED-LVS are selected from 4 sources (in priority order):

  • the 2020 version of Siena Galaxy Atlas (SGA; Moustakas et. al 2023) isophotal D25 SGA in the r-band, which are measured on the relatively deep optical DESI Legacy Imaging Surveys (Dey et al. 2019)
  • the Sloan Digital Sky Survey (SDSS; York et al. 2000) isophotal D25 SDSS in the r-band
  • the Two Micron All Sky Survey (2MASS; Skrutskie et al. 2006) "total" aperture diameter (Dtot) in the Ks-band
  • those from older photographic plate surveys (e.g., RC3; de Vaucouleurs et al. 1991) isophotal D25 PLATE in the B-band. 

We find that the median diameter ratios relative to SGA are 0.9, 1.0, and 0.75 for SDSS, 2MASS, and PLATE surveys, respectively, with 10-30% scatter. Over 80% of NED-LVS objects have been assigned a fiducial angular diameter, where 15.7% are from SGA, 35.1% are from SDSS, 29.9% are from 2MASS, 0.1% (N~2,100) are from PLATE surveys. For more details, see the “Documentation for data added after NED-LVS paper" section on the NED-LVS website. 

 

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