Polarized extended Lyα emission from a z=2.3 radio galaxy

A. Humphrey, J. Vernet, M. Villar Martín, S. Di Serego Alighieri, R. A. E. Fosbury, A. Cimatti

Abstract
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 Lyα 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 Lyα photons by HI. Not only is this the first detection of polarized Lyα around a radio-loud active galaxy, it is also the second detection to date for any kind of Lyα nebula. We also detect a pair of diametrically opposed UV continuum sources along the slit, at the outer edges of the Lyα 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.

Keywords
ISM: jets and outflows - galaxies: active - galaxies: high-redshift - galaxies: individual (TXS 0211-122)

Notes
galaxies: active - galaxies: high-redshift - galaxies: individual: TXS 0211-122 - ISM: jets and outflows

The Astrophysical Journal Letters
Volume 768, Page L3_1
May 2013

DOI: 10.1088/2041-8205/768/1/L3
ADS Bibliographic code: 2013ApJ...768L...3H