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J/other/JApA/32.567 Rotation measures in A2255 at 18, 21, 25, 85cm (Pizzo+ 2011)
The large scale structure: polarization aspects.
    Pizzo R.F.
   <J. Astrophys. Astron., 32, 567-576 (2011)>
   =2011JApA...32..567P
ADC_Keywords: Clusters, galaxy ; Radio sources ; Polarization

Keywords: galaxies: clusters: general -
          galaxies: clusters: individual (Abell 2255) -
          galaxies: intergalactic medium - magnetic fields - polarization

Abstract:
    Polarized radio emission is detected at various scales in the
    Universe. In this document, I will briefly review our knowledge on
    polarized radio sources in galaxy clusters and at their outskirts,
    emphasizing the crucial information provided by the polarized signal
    on the origin and evolution of such sources. Successively, I will
    focus on Abell 2255, which is known in the literature as the first
    cluster for which filamentary polarized emission associated with the
    radio halo has been detected. By using RM (plasma Rotation Measure)
    synthesis on our multi-wavelength WSRT observations, we studied the
    3-dimensional geometry of the cluster, unveiling the nature of the
    polarized filaments at the borders of the central radio halo. Our
    analysis points out that these structures are relics lying at large
    distance from the cluster center.

Description:
    After calibration, we produced Q and U channel images for each dataset
    and we inspected them to remove those affected by residual RFI (radio
    interferences) and/or problems related to specific telescopes. The
    final images were carried through for further processing in RM
    synthesis. To improve the resolution in RM space, as well as the
    sensitivity, we combined the 18, 21 and 25cm datasets, producing a
    single high-frequency RM cube. In addition, we made RM cubes at 85 
    and 200cm.
Objects:
    ----------------------------------------------
       RA   (2000)   DE       Designation(s)
    ----------------------------------------------
    17 12 50.04 +64 03 10.6   A2255 = ACO 2255
    ----------------------------------------------

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
list.dat         165        2   List of figures
fig/*              0        2   Figures (animated GIFs)


Byte-by-byte Description of file: list.dat

   Bytes Format Units   Label     Explanations

   1- 20  A20   ---     Fig       Figure name in subdirectory fig
  22- 24  F3.1  deg     FoV       Field of view (width and height)
  26- 30  I5    rad/m2  b_RM      Lower value of the rotation measure
  32- 36  I5    rad/m2  B_RM      Upper value of the rotation measure
  38- 39  I2    rad/m2  RM        Step in the rotation measure RM (10 or 4)
  41-165  A125  ---     Title     Title of the figure


Acknowledgements:
    Roberto Pizzo, pizzo(at)astron.nl
(End)                                      Patricia Vannier [CDS]    20-Mar-2012