Astronomy and Astrophysics Seminars

Low Frequency view of merging galaxy clusters

by Dr. M. PANDEY-POMMIER (Observatoire de Lyon, France)

Friday, November 20, 2015 from to (Asia/Kolkata)
at DAA ( A269 )
Description
 Cluster of galaxies are the largest gravitationally bounded systems
in our Universe.
 They emit non-thermal emission during merger events that takes the
form of cluster wide (Mpc-size)
 radio halos, mini-halos and relics, further implying the presence of
relativistic particles
 and magnetic fields within the intracluster medium. These sources
reveal a population of
 ultra-relativistic electrons coexisting with the intracluster thermal
gas. The origin of these
 relativistic electrons is one of the most intriguing problems of
cluster astrophysics.
 Further, the radio observations also show presence of micro-Gauss
level magnetic fields
 within the galaxy clusters, with values up to tens of μG at the center of
 cooling core clusters. In this presentation, I will discuss about the
new results
 on the low frequency nature of a few galaxy clusters observed with
the GMRT and LOFAR
 as well as their statistical properties. I will also outline the
important contribution
 that are expected in this area from sophisticated radio facilities
(like LOFAR, SKA, etc.)
 as well as synergies with ongoing survey with Multi Unit
Spectroscopic Explorer (MUSE)
 and India's first dedicated multi-wavelength space observatory, ASTROSAT.