Theoretical Physics Colloquium

How much does a galaxy know about its large-scale environment?

by Prof. Biswajit Pandey (Visva Bharati University, Bolpur)

Tuesday, August 29, 2017 from to (Asia/Kolkata)
at AG 69
Description
The small-scale environment characterized by the local density is known to play a crucial role in deciding the galaxy properties but the role of large-scale environment on galaxy formation and evolution still remains a less clear issue. We propose an information theoretic framework to investigate the influence oflarge-scale environment on galaxy properties and apply it to the data from the Galaxy Zoo project which provides the visual morphological classifications of 1 million galaxies from the Sloan Digital Sky Survey. We find a non-zero mutual information between morphology and environment which decreases with increasing length scales but persists throughout the entire length scales probed. We estimate the conditional mutual information and the interaction information between morphology and environment by conditioning the environment on different length scales and find a synergic interaction between them which operates up to at least a length scales of 30 Mpc/h. I will discuss about the possible origins of such interactions and present our conclusions on the role of large-scale environment on galaxy formation and evolution.
Material: