Abstract
A2319 is a massive, merging galaxy cluster with a previously detected radio halo that roughly follows the X-ray emitting gas. We present the results from recent observations of A2319 at~20 cm with theKarlG. JanskyVery LargeArray and a re-analysis of theX-ray observations from XMM-Newton, to investigate the interactions between the thermal and non-thermal components of the intracluster medium. We confirm previous reports of an X-ray cold front, and identify a distinct core to the radio halo, ~800 kpc in extent, that is strikingly similar in morphology to the X-ray emission, and drops sharply in brightness at the cold front. We also detect radio emission trailing off from the core that blends smoothly into the ~2 Mpc halo detected with the Green Bank Telescope (GBT). We speculate on the possible mechanisms for such a two-component radio halo, with sloshing playing a dominant role in the core. By directly comparing the X-ray and radio emission, we find that a hadronic origin for the cosmic ray electrons responsible for the radio halo would require a magnetic field and/or cosmic ray proton distribution that increases with radial distance from the cluster centre, and is therefore disfavoured.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 2495-2503 |
| Number of pages | 9 |
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 448 |
| Issue number | 3 |
| DOIs | |
| State | Published - Apr 11 2015 |
Bibliographical note
Funding Information:We thank Stefano Profumo and Elke Roediger for useful discussions. Partial support for this work at the University of Minnesota comes from grant AST-112595 from the National Science Foundation. ES acknowledges support from the Cota-Robles Fellowship. TEJ acknowledges support from the Hellman Fellows Fund. The VLA at the NRAO is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. This work is partly based on observations obtained with XMM- Newton, an ESA sciencemission with instruments and contributions directly funded by ESA Member States and the USA (NASA). The X-ray data were provided through the HEASARC XMM-Newton archive atNASA/GSFC. This research made use of theNASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract withNASA. This research made use of the software package SHERPA, provided by the Chandra X-ray Center. This research made use of ASTROPY, a community-developed core PYTHON package for astronomy (Robitaille et al. 2013).
Funding Information:
We thank Stefano Profumo and Elke Roediger for useful discussions. Partial support for this work at the University of Minnesota comes from grant AST-112595 from the National Science Foundation. ES acknowledges support from the Cota-Robles Fellowship. TEJ acknowledges support from the Hellman Fellows Fund. The VLA at the NRAO is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. This work is partly based on observations obtained with XMM– Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and the USA (NASA). The X-ray data were provided through the HEASARC XMM–Newton archive at NASA/GSFC. This research made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. This research made use of the software package SHERPA, provided by the Chandra X-ray Center. This research made use of ASTROPY, a community-developed core PYTHON package for astronomy (Robitaille et al. 2013).
Publisher Copyright:
© 2015 The Authors.
Keywords
- A2319-X-rays
- Clusters
- Clusters
- Galaxies
- Individual
- Non-thermal-galaxies
- Radiation mechanisms