Query : 2007A&A...470..969X

2007A&A...470..969X - Astronomy and Astrophysics, volume 470, 969-975 (2007/8-2)

Polarization observations of SNR G156.2+5.7 at λ6 cm.


Abstract (from CDS):

G156.2+5.7 is a large supernova remnant (SNR) first discovered in the ROSAT X-ray survey due to its exceptional high X-ray brightness. Subsequently detailed X-ray, optical and Hα studies of this SNR were made, but radio observations are rare because of its low surface brightness and large size. Radio continuum and polarization images of the SNR G156.2+5.7 at λ6 cm are presented for the first time to be discussed in the context with available data to investigate its physical properties. The SNR G156.2+5.7 was observed with the Urumqi 25m telescope in radio continuum and linear polarization. The results are analyzed together with 11cm and 21cm maps previously obtained with the Effelsberg 100 m telescope and compared with a broad-band X-ray ROSAT image, 100µm infrared radiation data and a Hα emission map. We obtained an integrated flux density for G156.2+5.7 of S_6 cm_=2.5±0.5Jy. The spectral index of the integrated emission is α=-0.48±0.08 (S~να) between λ74 cm and λ6cm excluding compact radio sources. We also obtained a spectral index map, which shows little variation between the shells and the central area of the SNR. This is consistent with the constant integrated flux density spectrum. Highly polarized radio emission has been detected from the SNR shell, but also from a central patch, which probably originates in the front part of the spherical SNR shell. We derived the distribution of rotation measure from polarization data at λ11cm and λ6cm and found RM gradients of opposite direction in the SNR shell. The SNR G156.2+5.7 is unusual by its exceptionally high X-ray brightness and very low surface-brightness in the radio range. The magnetic field is very well ordered along the shell periphery as expected for a compressed ambient magnetic field. A toroidal magnetic field component is indicated by the RM distribution.

Abstract Copyright:

Journal keyword(s): ISM: supernova remnants - radio continuum: ISM - polarization - ISM: magnetic fields

Simbad objects: 7

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Number of rows : 7
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 3C 48 QSO 01 37 41.2996631208 +33 09 35.080388820   16.62 16.20     ~ 2766 2
2 NAME Per Arm PoG 03 30 +45.0           ~ 1477 0
3 3C 130 rG 04 52 52.8370360032 +52 04 47.201456604   16.5       ~ 90 1
4 SNR G156.2+05.7 SNR 04 58 51.300 +51 50 28.00           ~ 127 1
5 ICRF J052109.8+163822 Sy1 05 21 09.88596258 +16 38 22.0515459   19.37 18.84 18.480   ~ 835 1
6 SNR G295.5+09.7 SNR 12 09 40 -52 25.0           ~ 281 1
7 SNR G039.2-00.3 SNR 19 04 03.9 +05 26 56           ~ 189 1

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