We present spatially resolved spectropolarimetic measurements of the 100-kpc scale gaseous environment of the z=2.34 radio galaxy TXS 0211-122. The polarization level of the narrow Ly-alpha emission is low centrally (P<5 %), but rises to P=16.4+/-4.6 % in the Eastern part of the nebula, indicating that the nebula is at least partly powered by the scattering of Ly-alpha photons by HI. Not only is this the first detection of polarized Ly-alpha around a radio-loud active galaxy, it is also the second detection to date for any kind of Ly-alpha nebula. We also detect a pair of diametrically opposed UV continuum sources along the slit, at the outer edges of the Ly-alpha nebula, which we suggest may be the limb of a dusty shell, related to the large-scale HI absorbers often associated with high-z radio galaxies.
@article{arxiv.1302.2813,
title = {Polarized extended Ly-alpha emission from a z=2.3 radio galaxy},
author = {A. Humphrey and J. Vernet and M. Villar-Martin and S. di Serego Alighieri and R. A. E. Fosbury and A. Cimatti},
journal= {arXiv preprint arXiv:1302.2813},
year = {2015}
}
Comments
Accepted for publication in Astrophysical Journal Letters