Milky Way galaxy-analogs and isolated galaxies with bars: environmental density in the Local Volume

Abstract

The environmental density of galaxies within the cosmic web constrains their 3D locations in filaments, voids, groups, and clusters. It traces the distribution of baryons and the influence of dark-matter halos on galaxy evolution, and helps diagnose external processes such as supernova and AGN feedback, tidal interactions, ram-pressure stripping, and large-scale flows. We focus on isolated barred galaxies, the parent population that includes Milky Way analogs. To measure local environmental density and verify isolation (|Delta v| <= 500 km s^-1), we built a Python pipeline that works in two redshift regimes: low (z0 < 0.02) and high (z0 >= 0.02). Densities were estimated with k-nearest neighbors and Voronoi tessellations and classified as void (Sigma < 0.05), filament (0.05 <= Sigma < 0.5), group (0.5 <= Sigma < 2.0), and cluster (Sigma >= 2.0). Our northern-sky sample contains 311 isolated barred galaxies from 2MIG plus Milky Way analog systems (z < 0.07). We find 157 void, 84 filament, 27 group, and 11 cluster galaxies; 30 have no detected neighbors. Sixty-seven lie in extremely low-density regions (Sigma_3D < 0.01 gal Mpc^-3), and 22 have the nearest companion beyond 5 Mpc, indicating residence in extended voids. The Milky Way (Sigma_5NN ~ 0.13 gal Mpc^-3, R ~ 2.1 Mpc) and its close analog NGC 3521 both lie in filamentary environments at the edge of a nearby void. For z > 0.02 we identify three additional Milky Way analog candidates from the density metrics: CGCG 208-043 (3D Voronoi) and NGC 5231 and CGCG 047-026 (5th-nearest neighbor). These results show that local environmental density is an effective, physically motivated criterion for selecting Milky Way analogs.

20 pages, 6 figures. Paper submited to Space Science and Technology

References in corpus (22)

• HyperLEDA. III. The catalogue of extragalactic distances
• The Abundance Properties of Nearby Late-Type Galaxies.I. The Data
• Reconstructing the Last Major Merger of the Milky Way with the H3 Survey
• The relation between star formation, morphology and local density in high redshift clusters and groups
• A Comparative Study of Density Field Estimation for Galaxies: New Insights into the Evolution of Galaxies with Environment in COSMOS out to z~3
• From voids to filaments: environmental transformations of galaxies in the SDSS
• Triggering optical AGN: the need for cold gas, and the indirect roles of galaxy environment and interactions
• The Araucaria Project: Distance to the Local Group Galaxy NGC 3109 from Near-Infrared Photometry of Cepheids
• A Council of Giants
• Catalog of Isolated Galaxies Selected from the 2MASS Survey
• A simultaneous solution to the Hubble tension and observed bulk flow within 250 $h^{-1}$ Mpc
• Evidence of Bar-induced Secular Evolution in the Inner Regions of Stellar Discs in Galaxies: What Shapes Disc Galaxies?
• High-order 3D Voronoi tessellation for identifying Isolated galaxies, Pairs and Triplets
• The AMIGA sample of isolated galaxies. VII. Far-infrared and radio continuum study of nuclear activity
• Looking for a needle in a haystack: Measuring the length of a stellar bar
• Searching for Milky Way twins: Radial abundance distribution as a strict criterion
• A robust determination of halo environment in the cosmic field
• Machine learning technique for morphological classification of galaxies from the SDSS. III. Image-based inference of detailed features
• Machine learning technique for morphological classification of galaxies from SDSS. II. The image-based morphological catalogs of galaxies at 0.02<z<0.1
• Discovery of the Polar Ring Galaxies with deep learning
• A Bayesian catalog of 100 high-significance voids in the Local Universe
• NGC3521 as the Milky Way analogue: spectral energy distributon from UV to Radio and photometric variability