We aim to summarize the current state of knowledge regarding Galactic Faraday rotation in an all-sky map of the Galactic Faraday depth. For this we have assembled the most extensive catalog of Faraday rotation data of compact extragalactic polarized radio sources to date. In the map-making procedure we used a recently developed algorithm that reconstructs the map and the power spectrum of a statistically isotropic and homogeneous field while taking into account uncertainties in the noise statistics. This procedure is able to identify some rotation angles that are offset by an integer multiple of π. The resulting map can be seen as an improved version of earlier such maps and is made publicly available, along with a map of its uncertainty. For the angular power spectrum we find a power law behavior C l ∞ l -2.17 for a Faraday sky where an overall variance profile as a function of Galactic latitude has been removed, in agreement with earlier work. We show that this is in accordance with a 3D Fourier power spectrum P(k) ∞ k -2.17 of the underlying field n e B r under simplifying geometrical and statistical assumptions. © 2012 ESO.
An improved map of the Galactic Faraday sky / Oppermann, N.*; Junklewitz, H.; Robbers, G.; Bell, M.R.; Enßlin, T.A.; Bonafede, A.; Braun, R.; Brown, J.C.; Clarke, T.E.; Feain, I.J.; Gaensler, B.M.; Hammond, A.; Harvey-Smith, L.; Heald, G.; Johnston-Hollitt, M.; Klein, U.; Kronberg, P.P.; Mao, S.A.; McClure-Griffiths, N.M.; O'Sullivan, S.P.; Pratley, L.; Robishaw, T.; Roy, S.; Schnitzeler, D.H.F.M.; Sotomayor-Beltran, C.; Stevens, J.; Stil, J.M.; Sunstrum, C.; Tanna, A.; Taylor, A.R.; Van Eck, C.L.. - In: ASTRONOMY & ASTROPHYSICS. - ISSN 0004-6361. - ELETTRONICO. - 542:(2012), pp. A93.A93-A93.106. [10.1051/0004-6361/201118526]
An improved map of the Galactic Faraday sky
Bonafede, A.;Johnston-Hollitt, M.;
2012
Abstract
We aim to summarize the current state of knowledge regarding Galactic Faraday rotation in an all-sky map of the Galactic Faraday depth. For this we have assembled the most extensive catalog of Faraday rotation data of compact extragalactic polarized radio sources to date. In the map-making procedure we used a recently developed algorithm that reconstructs the map and the power spectrum of a statistically isotropic and homogeneous field while taking into account uncertainties in the noise statistics. This procedure is able to identify some rotation angles that are offset by an integer multiple of π. The resulting map can be seen as an improved version of earlier such maps and is made publicly available, along with a map of its uncertainty. For the angular power spectrum we find a power law behavior C l ∞ l -2.17 for a Faraday sky where an overall variance profile as a function of Galactic latitude has been removed, in agreement with earlier work. We show that this is in accordance with a 3D Fourier power spectrum P(k) ∞ k -2.17 of the underlying field n e B r under simplifying geometrical and statistical assumptions. © 2012 ESO.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
