Infrared imaging and polarimetric observations of the pulsar wind nebula in SNR G21.5-0.9

¹ Department of Astrophysics, N. Copernicus Astronomical Center, ul. Rabiańska 8, 87-100 Toruń Poland
e-mail: zajczyk@ncac.torun.pl
² LUPM, Université Montpellier 2, CNRS/IN2P3, place E. Bataillon, 34095 Montpellier, France
³ Center for Astrophysics (CfA), 60 Garden Street, Cambridge, MA 02138, USA
⁴ North Carolina State University Physics Dept., Box 8202, Raleigh, NC 27695-8202, USA
⁵ INAF – Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
⁶ Service d’Astrophysique, CEA-Saclay, 91191 Gif-sur-Yvette Cedex, France
⁷ ESO, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany

Received: 5 May 2011
Accepted: 17 April 2012

Abstract

We present infrared observations of the supernova remnant G21.5-0.9 with the Very Large Telescope, the Canada-France-Hawaii Telescope and the Spitzer Space Telescope. Using the VLT/ISAAC camera equipped with a narrow-band [Fe II] 1.64 μm filter the entire pulsar wind nebula in SNR G21.5-0.9 was imaged. This led to detection of iron line-emitting material in the shape of a broken ring-like structure following the nebula’s edge. The detected emission is limb-brightened. We also detect the compact nebula surrounding PSR J1833-1034, both through imaging with the CFHT/AOB-KIR instrument (K′ band) and the IRAC camera (all bands) and also through polarimetric observations performed with VLT/ISAAC (K_s band). The emission from the compact nebula is highly polarised with an average value of the linear polarisation fraction , and the swing of the electric vector across the nebula can be observed. The infrared spectrum of the compact nebula can be described as a power law of index α_IR = 0.7 ± 0.3, and suggests that the spectrum flattens between the infrared and X-ray bands.