observations of snr g156.2+5.7 at 6cm
DESCRIPTION
Observations of SNR G156.2+5.7 at 6cm. JianWen Xu, Li Xiao, XiaoHui Sun, Chen Wang, Wolfgang Reich, JinLin Han Partner Group of MPIfR at NAOC. System parameters/Calibrators. Central frequency: 4.8 GHz Bandwidth: 600 MHz System temperature: 22-25 K HPBW: 9.5 arcmin - PowerPoint PPT PresentationTRANSCRIPT
Observations of SNR G156.2+5.7 at 6cm
JianWen Xu, Li Xiao, XiaoHui Sun, Chen Wang,
Wolfgang Reich, JinLin Han
Partner Group of MPIfR at NAOC
System parameters/Calibrators• Central frequency: 4.8 GHz• Bandwidth: 600 MHz• System temperature: 22-25 K• HPBW: 9.5 arcmin• Aperture efficiency: 62%• Beam efficiency: 67%• Conversion factor: 0.164 K/Jy• r.m.s: 1.5 mK for 1s integration tim• Primary Calibrator: 3C138
– Intensity: 3.64 Jy, – Polarization Angle: 169 deg, – Polarization Percent: 11.7%
Properties of SNR G156.2+5.7
• Identified firstly by the ROSAT observatory in the all-sky survey for X-ray sources
• Among the 10 brightest X-ray Galactic SNRs
• The lowest radio surface brightness among all known SNRs
• Common magnetic field strength & therefore a low electron density
Some Parameters of SNR G156.2+5.7
• Spectral index = 0.50.15 (Reich et al. 1992)
• A distance of d 3kpc (Pfeffermann et al. 1991)
• A diameter of 108’, or 95pc (Pfeffermann et al. 1991)
• Type I progenitor SN of E0 = 1051erg (Reich et al. 1992)
• An age of 2.6104yr (Pfeffermann et al. 1991)
• r.m.s: 1.0 mK in I
• Flux density:2.2+/-0.6Jy
• polarization percentage :
Left:<= 40%,
Right:<=70%
G156.2+5.7
• one of the most weak SNRs • The red source in the southwest with strongest radio emission is probably an extragalactic one
Total intensity (image)
• r.m.s: 1.0 mK in I
• Flux density:2.2+/-0.6Jy
• polarization percentage :
Left:<= 40%,
Right:<=70%
G156.2+5.7
Total intensity (image+contours)
• one of the most weak SNRs • The red source in the southwest with strongest radio emission is probably an extragalactic one
• r.m.s: 1.0 mK in I
• Flux density:2.2+/-0.6Jy
• polarization percentage :
Left:<= 40%,
Right:<=70%
G156.2+5.7
Intensity (image) + B (bars) + Polarization Intensity (contours)
• one of the most weak SNRs • small patchy of polarization in the center
---probably local structure
• r.m.s: 0.25 K TB in I
• Flux density:4.2+/-1.0Jy
• polarization percentage :
unavailable
G156.2+5.7
Intensity (image+contours) (Reich et al. 1992)
• one of the most weak SNRs • The source in the southwest with strongest radio emission is probably an extragalactic one
• r.m.s: unavailable
• Flux density:3.0+/-1.0Jy
• polarization percentage :
Left:<= 75%,
Right:<=50%
G156.2+5.7
Intensity (image) + B (bars) + Polarization Intensity (contours)(Reich et al. 1992)
• one of the most weak SNRs • small patchy of polarization in the center ---probably local structure
• r.m.s: 0.5 mK in PI
• Flux density:2.2+/-0.6Jy
• Polarization percentage :
Left:<= 40%,
Right:<=70%
G156.2+5.7
Polarization Intensity (contours)
• one of the most weak SNRs
• small patchy of polarization in the center ---probably local structure
• r.m.s: 0.5 mK in PI
• Flux density:2.2+/-0.6Jy
• polarization percentage :
Left:<= 40%,
Right:<=70%
G156.2+5.7
Polarization Intensity (contours) + B (bars)
• one of the most weak SNRs • small patchy of polarization in the center ---probably local structure
• r.m.s: unavailable
• Flux density:3.0+/-1.0Jy
• polarization percentage :
Left:<= 75%,
Right:<=50%
G156.2+5.7
Polarization Intensity (contours) + B (bars) (Reich et al. 1992)
• one of the most weak SNRs • small patchy of polarization in the center ---probably local structure
• r.m.s: 1.0 mK in I, 0.5 mK in PI• Flux density:2.2+/-0.6Jy• polarization percentage : Left:<
= 40%, Right:<=70%
G156.2+5.7
Polarization Percentage (contours)
• one of the most weak SNRs • small patchy of polarization in the center ---probably local structure
Integrated flux densities
--by open circle
(derived from our observations)
--by filled circle
(taken from Reich et al. 1992)
G156.2+5.7
Radio spectrum at 4.8 GHz
Spectral index
= 0.540.06
Summary
• Total flux density is 2.2 0.6 Jy at 4.8GHz
• Spectral index is = 0.540.06
• Surface brightness = 2.910-22 W m-2 Hz-1 sr-1
at 4.8GHz
Thank You