Gastaldello, Fabio4; Wik, Daniel R.8; Molendi, S.4; Westergaard, Niels Jørgen Stenfeldt1; Hornstrup, Allan1; Madejski, G.6; Ferreira, Desiree Della Monica1; Boggs, S. E.9; Christensen, Finn Erland1; Craig, W. W.9
1 National Space Institute, Technical University of Denmark2 Astrophysics, National Space Institute, Technical University of Denmark3 IT-Department, National Space Institute, Technical University of Denmark4 National Institute for Astrophysics5 NASA Goddard Space Flight Center6 SLAC National Accelerator Laboratory7 University of California at Berkeley8 NASA Goddard Space Flight Center9 University of California at Berkeley
We present the results of a 55 ks NuSTAR observation of the core of the Coma Cluster. The global spectrum can be explained by thermal gas emission, with a conservative 90% upper limit to non-thermal inverse Compton (IC) emission of 5.1 × 10-12 erg cm-2 s-1 in a 12' × 12' field of view. The brightness of the thermal component in this central region does not allow more stringent upper limits on the IC component when compared with non-imaging instruments with much larger fields of view where claims of detections have been made. Future mosaic NuSTAR observations of Coma will further address this issue. The temperature map shows a relatively uniform temperature distribution with a gradient from the hot northwest side to the cooler southeast, in agreement with previous measurements. The temperature determination is robust given the flat effective area and low background in the 3-20 keV band, making NuSTAR an ideal instrument to measure high temperatures in the intracluster medium.