Alma Mater Studiorum Universit`a degli Studi di Bologna ... - Inaf
Alma Mater Studiorum Universit`a degli Studi di Bologna ... - Inaf
Alma Mater Studiorum Universit`a degli Studi di Bologna ... - Inaf
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112 6. Faraday rotation in two extreme environments<br />
IMAGE: 07_PSPC_CONVL_AS_1.3_OGEOM.FITS<br />
CNTRS: 07_1.3_I_4.FITS<br />
0 0.0002 0.0004 0.0006 0.0008<br />
37 49 00<br />
50 kpc<br />
DECLINATION (J2000)<br />
37 48 00<br />
37 47 00<br />
37 46 00<br />
37 45 00<br />
07 58 40<br />
07 58 30<br />
RIGHT ASCENSION (J2000)<br />
07 58 20<br />
Figure 6.1: Overlay of the X-ray emission (ROSAT PSPC) around 0755+37 on ra<strong>di</strong>o contours at<br />
1.385 GHz at 4.0 arcsec resolution.<br />
Table 6.3: Frequencies, bandwidths and angular resolutions used in the RM and Burn law k<br />
images. Details of the 0755+37 dataset are given in the Appen<strong>di</strong>x.<br />
source ν ∆ν beam<br />
[MHz] [MHz] [arcsec]<br />
0755+37 1385.1 12.5 1.3-4.0<br />
1464.9<br />
4860.1 100<br />
M 87 4635.1 50 0.4<br />
4735.0<br />
4835.1<br />
4935.0<br />
8085.1<br />
8335.1<br />
8535.1<br />
8785.1<br />
by G.B. Taylor. The RM maps were calculated only at pixels with polarization angle uncertainties<br />
≤10 ◦ at all frequencies. The RM maps have not been corrected for the Galactic contribution. For<br />
0755+37, this is estimated to be negligible (-1±2 rad m −2 ; Simard-Norman<strong>di</strong>n et al. 1981). For<br />
M 87, the value is less well-determined, but the source is at very high Galactic latitude, and the<br />
associated RM must be very small compared with the measured values (see below). Values of<br />
σ RM integrated over the maps are not corrected for the fitting errorσ RMfit ,<br />
I produced Burn law k images at the same resolutions and using the same frequencies as the<br />
RM maps. Weighted least-squares fits were made to the fractional polarization maps ln p(λ) as a<br />
112