Independent Component Analysis for Dimension Reduction Classification: Hough Transform and Mixture Modeling
Asis Kumar Chattopadhyay1, Tanuka Chattopadhyay2, Tuli Ghosh1, Saptarshi Mondal1
1Statistics, Calcutta University, Kolkata, West Bengal, India; 2Applied Mathematics, Calcutta University, Kolkata, West Bengal, India

The galaxies with low luminosities, low metallicities having smaller sizes are termed as 'dwarf galaxies'. The distinguishing criteria between 'giants' and 'dwarfs are generally absolute V magnitude (Mv ≤ -18) or mass (∼ 1/10 or 1/100 of M*). But masses are not known for most of the dwarf galaxies, so luminosity criterion is widely used for differentiating 'dwarfs' from 'giant galaxies'. Study of dwarf galaxies is important from the aspect of evolution of early Universe as they are considered as the counterparts of early galaxy forming fragments – especially low mass dwarfs which have few star formation episodes compared to more massive systems.

Globular clusters (GCs) are touchstones of astrophysics. Their study addresses many important issues ranging from stellar evolution to the formation of galaxies and cosmology. However, their origin and formation history, which are obviously linked to that of their parent galaxy, are still poorly understood.

For clustering and classification the primary task is to select the appropriate variables which significantly responsible for the variation. Principal Component Analysis method suffers from different limitations. Independent Component Analysis for dimension reduction is an appropriate method. For classification and clustering we are interested in a global correlation clustering based on the Hough transform.

Keywords: Independent component analysis; Robust clustering; Galaxies; Globular clusters

Biography: Prof. Asis Kumar Chattopadhyay is a Professor of Statistics from Calcutta University, India. He is a Visiting Associate of Inter University Centre for Astronomy and Astrophysics (IUCAA) Pune, India and also the Coordinator of IUCAA Resource Centre at Kolkata. He has actively participated in the development of Virtual Observatory, India.