Abstract Details
| Name: Lijo Thomas George Affiliation: Raman Research Institute Conference ID: ASI2016_744 Title : Low Frequency Study of Merging Galaxy Clusters using the MWA Authors and Co-Authors : K. S. Dwarakanath (RRI), M. Johnston-Hollitt (VWU), H. Intema (Leiden), N. Hurley-Walker (Curtin), L. Pratley (VWU) et al. Abstract Type : Oral Abstract Category : Extragalactic astronomy Abstract : Diffuse radio emission from galaxy clusters is seen in the form of central halos or peripheral arc-like relics. Clusters that exhibit signs of merging activity are more likely to host these halos and relics than those that don't. With a motivation to understand the formation of halos and relics in galaxy clusters we have studied 9 clusters using the data from the Murchison Widefield Array. Either double or single relics have been detected in these clusters from earlier higher radio frequency (1400 MHz) observations. In addition, radio haloes have also been detected in 4 of these clusters at 1400 MHz. We have analysed the images of these clusters from the GaLactic and Extragalactic All-sky MWA (GLEAM) Survey at 5 frequencies (88, 118, 154, 188 and 215 MHz). Furthermore, we have made a detailed comparison of the MWA images of these clusters at 154 MHz with those created by us from archival data of the 150 MHz GMRT Sky Survey (TGSS). We have estimated the spectra of all the relics in the frequency range 80--1400 MHz and are exploring the implications to the synchrotron lifetimes of the relics and to the dynamical timescales of the cluster merger. We have also detected the known halo emission in 4 of these clusters and established their spectra over the range 80--1400 MHz. Additionally, we have obtained stringent upper limits to the halo emission in the remaining clusters. We discuss these preliminary results and the implications of the spectra of the relics and the limits on the halo emission for cluster formation and merger history. |