Abstract Details

Name: Surajit Paul
Affiliation: Department of Physics, SP Pune University
Conference ID: ASI2017_762
Title : Possible discovery of multiple shock structures and filamentary inroads to massive galaxy clusters by uGMRT and SKA
Authors and Co-Authors : 1. Prateek Gupta, Dept. of Physics, SP Pune University 2. Reju Sam John, PEC, Pondichery 3. Abhirup Datta, Centre for Astronomy, IIT Indore 4. Siddharth Malu, Centre for Astronomy, IIT Indore
Abstract Type : Oral
Abstract Category : General Relativity and Cosmology
Abstract : The structures at Large-Scales ( > few tens of Mpc) in the Universe comprises of complex filamentary network of matters surrounding the large voids and they connect the massive Galaxy Clusters. Massive objects like galaxy clusters become very interesting, especially when in a merging state. Such events has been detected and studied in plenty in the last decades. But there are more interesting components that are yet to be detected in radio waves. This vital component of cosmological structures are the main channels through which dark matter and baryons drains from voids and reach the nodes where the Clusters are formed. As most of the matters are processed for the first time at the filamentary surfaces and the accretion zones of Galaxy Clusters, these are the region that contain a wealth of information about the structure formation energetics. Both the mergers shocks and baroclinic instability at the entry of filaments to the Galaxy clusters generate a significant turbulence and high degree of magnetic fields are amplified. Charged particles are accelerated in this structures through shocks and turbulence. As a result such objects then expected to produce significant amount of synchrotron radio emission due to the motion of accelerated charge particles in the enhanced magnetic field and helps in tracing back the dynamical history of these structures. In this work, we have simulated many high resolution (~15 kpc) realisations of 128^3 Mpc h^{-1} cosmological volume using ENZO hydrodynamic code. We have then formulated and implemented Diffusive Shock Acceleration and Turbulent re-acceleration models to compute the possible radio emission from the galaxy clusters and outskirts. Our modelled predictions revealed an unique structure at the filamentary entry. These filamentary inroads are expected to be observed as long trails of parallel, linear and radial radio structures in the cluster periphery. Most surprisingly these structures that are beyond the virial radius, have radio emission power only an order lower than the usual radio halos making it possible to detect with even uGMRT. Our study also reveal the possible multiple shock structures including multiple merger shocks and virial shocks. Though the virial shock is at the level of sub micro Jy in 610 GHz band, which is quite difficult to observe, an intermediate merger shocks at 2-3 Mpc away from the centre and the filamentary inroads have few 10s of $\mu$J of radio power and very much possible that SKA will detect such structures easily. These detections not only will reveal the actual extent of the galaxy clusters, it will also give us an idea about the missing baryons and WHIMs present in the filaments.