Abstract Details

Name: DEEPAK CHANDRA JOSHI
Affiliation: NATIONAL CENTRE FOR RADIO ASTROPHYSICS TATA INSTITUTE OF FUNDAMENTAL RESEARCH
Conference ID: ASI2021_409
Title : A multi-frequency study of the radio halo in the merging galaxy cluster PLCKESZ G171.94-40.65
Authors and Co-Authors : 1.DEEPAK CHNADRA JOSHI-NATIONAL CENTRE FOR RADIO ASTROPHYSICS-TIFR 2.DR. RUTA KALE-NATIONAL CENTRE FOR RADIO ASTROPHYSICS-TIFR
Abstract Type : Poster
Abstract Category : Extragalactic Astronomy
Abstract : Clusters of galaxies are the largest gravitationally bound systems in the universe that contain dark matter, galaxies and the intra-cluster medium (ICM). The ICM is mainly very hot thermal plasma (detected as X-ray emission from galaxy clusters) but also contains large scale magnetic field and cosmic rays that elude detection in most frequency bands. The relativistic electrons in presence of the magnetic field produce synchrotron emission detectable in radio bands. The extended diffuse radio sources in galaxy clusters are direct probes of the magnetic field and cosmic ray electrons. It has been observed that massive galaxy clusters (M500>5.0*10^(14)solar masses) are more likely to have this large scale diffuse radio sources spread around the centre called radio halos but their origin and evolution is still a matter of debate. One such giant radio halo was discovered in the merging galaxy cluster PLCKESZ G171.94-40.65 (Giacintucci et al 2013) using NRAO VLA Sky Survey and short GMRT observations. We present the images of this cluster with deep GMRT data at 235, 325 and 610 MHz and the VLA-C and D at 1-2 GHz. The integrated spectral index of the radio halo is -1.4 placing it on the border line between normal and ultra-steep spectrum radio halos. We also present the spectral index map of the radio halo. We will discuss the relation between the ongoing merger and the radio halo properties in the context of the theoretical models.