Analyzing the cosmic architecture in the vicinity of Grand-design and Flocculent spiral galaxies with Local Geometric Index

Suman Sarkar, Ganesh Narayanan, Arunima Banerjee

Published 2023-02-16Version 1

We explore the environment of 351 Grand-design and 541 Flocculent spiral galaxies recently identified employing machine learning techniques from the $17^{th}$ data release of Sloan Digital Sky Survey. We introduce a novel estimator called the Local Geometric Index to quantify the morphology of the local environment of these 892 galaxies. Based on the Local Geometric Index of the galaxies, we identify their local environments to be void, sheet, filament or cluster. We find that the Grand-designs are mostly located in dense environments like clusters and filaments, whereas the Flocculents lie in sparse environments in voids and sheets. A $p$-value $<$ $10 ^{-10}$ from a Kolmogorov-Smirnov test indicates that our results are statistically significant at $99.9\%$ confidence level. Further, we note that dense environments with large tidal flows are dominated by the Grand-designs. Metal-poor environments, such as sheets and voids, with a high abundance of gas clouds, on the other hand, are mostly populated by the Flocculents.