Detection of a radio bridge in Abell 3667
Abstract
We have detected a radio bridge of unpolarized synchrotron emission connecting the NW relic of the galaxy cluster Abell 3667 to its central regions. We used data at 2.3 GHz from the S-band Polarization All Sky Survey (S-PASS) and at 3.3 GHz from a follow up observation, both conducted with the Parkes Radio Telescope. This emission is further aligned with a diffuse X-ray tail, and represents the most compelling evidence for an association between intracluster medium turbulence and diffuse synchrotron emission. This is the first clear detection of a bridge associated both with an outlying cluster relic and X-ray diffuse emission. All the indicators point toward the synchrotron bridge being related to the post-shock turbulent wake trailing the shock front generated by a major merger in a massive cluster. Although predicted by simulations, this is the first time such emission is detected with high significance and clearly associated with the path of a confirmed shock. Although the origin of the relativistic electrons is still unknown, the turbulent re-acceleration model provides a natural explanation for the large-scale emission. The equipartition magnetic field intensity of the bridge is B_eq = 2.2 +/- 0.3 \mu G. We further detect diffuse emission coincident with the central regions of the cluster for the first time.
Keywords
Cite
@article{arxiv.1205.1082,
title = {Detection of a radio bridge in Abell 3667},
author = {E. Carretti and S. Brown and L. Staveley-Smith and J. M. Malarecki and G. Bernardi and B. M. Gaensler and M. Haverkorn and M. J. Kesteven and S. Poppi},
journal= {arXiv preprint arXiv:1205.1082},
year = {2015}
}
Comments
10 pages, 16 figures, accepted for publication on MNRAS. Replaced with the version accepted for publication: also the 3.3 GHz image cleaned from compact sources; 8 more figures; details on data reduction and compact source cleaning added; new estimate of the magnetic field. Some figures at resolution lower than the original ones