1. Primary results of polarization survey of large-SNRs at 6cm Li Xiao, XiaoHui Sun, Chen Wang, WeiBin Shi, Wolfgang Reich, JinLin Han Partner Group of MPIfR at NAOC

2. outlines System parameter of Urumqi 25m telescope How we choose the observation target? The large-SNRs observation list preliminary results The future work

3. System parameters/Calibrators Central frequency: 4800 MHz 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 time Primary Calibrator: 3C286 –Intensity: 7.5 Jy, –Polarization Angle: 33 deg, –Polarization Percent: 11.3%

4. How we choose the observation target? Urumqi 25m telescope observation condition: DEC>-30 deg 111 SNRs at dec >-30 deg (D.A.Green cataloge) Object scale : X>80’ or X+Y>120’, Our target is 19 large-SNRs (15 already observed)

5. the large-SNRs observation list Name Size Scan size obs.times G28.8+1.5 100 3*3 0 G39.7-2.0(W50, SS433) 120*60 3*3 0 G65.1+0.690*50 3*3 1 G69.0+2.7(CTB80) 80 3*3 2 G74.0-8.5(Cygnus loop) 230*160 4.2*4.8 5 G82.2+5.3(W63) 95*65 4.2*4.24 G89.0+4.7(HB21) 120*90 3*36 G93.7-0.2(CTB104A, DA551)80 3*36 G114.3+0.3 90*55 3*34 G116.5+1.1 80*60 3*34 G119.5+10.2(CTA1) 90 3*37 G126.2+1.6 & G127.1+0.5 70 4*4 4 G132.7+1.3(HB3) 80 5*54 G156.2+5.7 110 3*3 8 G160.9+2.6(HB9) 140*120 4*46 G166.2+2.5OA184 90*70 5*5 4 G180-1.7(S147)180 5*52 G205.5+0.5220 5*50

6. Preliminary result W63 HB21 HB9 G156.2+5.7 G114.3+0.3 G116.5+1.1 10 good maps reduced in all CTB104A (G93.7+0.2) Cygnus loop(G74.0-8.5) G126.2+1.6 & G127.1+0.5 CTA1 (G119.5+10.2)

7. Previous Observations: –Radio: the remnant locates in the Cygnus X complex. It displays a non-circular,elliptical shape in radio map –Optical: in complex region, but spectra indicate SNR filaments –X-rays: Einstein and ROSAT detected Our Observation –3 coverages –Flux density: 46 +/- 5 Jy –First complete map at highest frequency up to data W63 (G82.5+5.3) Size: 95’X65’; Type:S; Dist:1.3~1.9 kpc

8. ROSAT image (soft X-ray) + radio contours(326Mhz) 5Ghz (Angerhofer et al. 1977) Effelsberg 100m 2.7Mhz (Reich et al. 2003) 326Mhz (Rengelink et al. 1997)

9. Previous observation: –Radio : distorted shell; 4C50.52, an extragalactic double within the boundary of the remnants –Optical: filaments possibly associated –X-rays : Centrally brightended Our observation: –4 coverages –Flux density:114 +/- 11 Jy –First Total Intensity and Polarization observation at highest frequency up to data HB21 (G89.0+4.7) Size: 120’ X 90’; Type: S; Distance: 0.8 kpc;

10. ROSAT image (leahy et al. 1996) 11cm (haslam et al. 1975) 35cm (Reich et al. 2003) 408Mhz (Tatematsu et al. 1990)

11. Previous Observations: –Radio: large, filamentary shell; Pulsar within boundary of the remnant, plus several nearby compact sources –Optical: incomplete shell –X-rays: Centrally brightened Our Observation –4 coverages –Flux density: 35 +/- 4 Jy –First Polarization observation at highest frequency up to data HB9 (G160.9+2.6) Size: 140’X120’; Type: S; Dist: 4kpc

12. 4.7Ghz (leahy et al. 1998) 863Mhz (Reich et al. 2003) 151Mhz (leahy et al. 1998) ROSAT image (leahy et al. 1995)

13. Previous Observations: –Radio: faint shell, distorted with many protrusions, radio source in north is SNR 3C434.1, in south is HII region –X-rays: no detected Our Observation: –3 coverages –Flux density: 26 +/- 3 Jy; –The sensitivity 10 times larger than the previous observation at 4.75Ghz CTB104A (G93.7+0.2) Size: 80’; Type: S; Dist: 1.5kpc

14. 2.7Ghz (Velusamy & Kundu 1974) 1.7Ghz (Mantovani et al. 1982) 4.75Ghz (Mantovani et al. 1991) 1.4Ghz 408Mhz

15. Previous Observations: –Radio: shell, with HII region S165 within the boundary of the remnant. Plusar 2334+61 near centre of remnant. –Optical: faint emission in centre and to S. –X-rays: no detected Our Observation: –3 coverages –flux density:7.9 +/- 1 Jy –First Polarization observation at highest frequency up to data G114.3+0.3 Size: 90’X55’; Type: S; Dist: 3.0~3.8kpc

16. 2.7Ghz (Reich et al. 1981) 4.7Ghz (condon et al. 1994) 1.4Ghz (Uraniker et al. 2004)

17. Previous Observations: –Radio: G116.5+1.1 distinct shell, with high polarization. CTB1 incomplete shell, with pulsar to NE –X-rays: ROSAT detected for CTB1 Our Observations: –4 coverages –Flux density: G116.5+1.1: 7.4 +/- 1 Jy CTB1: 5.2 +/- 1 Jy –First Total Intensity and Polarization observation at highest frequency up to data for G116.5+1.1 G116.5+1.1 Size: 80’X60’; Type: S; Dist: 3.6~5.2kpc & CTB1 Size: 34’; Type: S; Dist: 2.7kpc

18. 2.7Ghz (Reich et al. 1981) 1.4Ghz (Uraniker et al. 2004) ROSAT image of CTB1 (Craig et al. 1997) 4.8Ghz of CTB1 (Angerhofer et al. 1977) CTB1

19. Previous Observations: –Radio: G126.2+1.6 poorly defined shell; with weak polarization G127.1+0.5 distinct shell, bright central source be extragalactic active galaxy. –Optical: detected Our Observation: –4 coverages –Flux density: G126.2+1.6: 4 +/- 1Jy; G127.1+0.5: 10 +/- 1Jy –First polarization observation for G126.2+1.6 up to data G126.2+1.6 Size: 70’; Type: S?; Spectral Index: varies & G127.1+0.5 Size: 45’; Type: S; Dist: 1.2-1.3kpc

20. 408Mhz (Joncas et al. 1989) 863Mhz1.4Ghz 2.7Ghz (furst et al. 1983) 4.8Ghz (furst et al. 1984) G127.1+0.5

21. Previous Observations : –Radio: incomplete shell; typical structure of breakout; compact, central X/gamma-ray source. –Optical: faint diffuse nebulosities. –X-rays: centrally brightened Our Observation: –6 coverages –Flux density: 12 +/- 1 Jy –First Total Intensity and Polarization observation at the highest frequency up to data CTA1 (G119.5+10.2) Size: 90’; Type: S; Dist: 3.6~5.2kpc

22. 1.4Ghz (image) + ROSAT (contours) 1.7Ghz (Sieber et al. 1981) 2.7Ghz (Sieber et al. 1981) 151Mhz (Sieber et al. 1981)

23. G156.2+5.7 Size: 110’; Type: S; Spectral Index: 0.5 Previous Observations: –Radio: faint shell –X-Ray: central brightened Our Observation: –5 coverages –Flux density: 4 +/- 1 Jy –One of the most weak SNR observed

24. 1.4Ghz (Reich et al. 1992) 2.7Ghz (Reich et al. 1992) ROSAT image (Pfeffermann et al. 1991)

25. 5 coverages; r.m.s: 1.0 mK in I, 0.4 mK in PI; Flux density: 90 +/- 9 Jy  Spectral index: 0.40 polarization percentage: <= 35% Cygnus loop (G74.0-8.5) confirm the variable character of CL 4 with timescale of ~30days distorted magnetic field in the northern part indicating strong interaction between blast wave and cloud the polarization image support the two-SNR scenario

26. The future work by combing the maps at other radio bands –make the spectral index maps –calculate the RM maps –polarization and depolarization analysis by combing X-ray observation altogether by statisticing the physics properties of SNRs  Better understand the physical process  constrain the theoretical models

27. Thank you!

28. CTB104A (G93.7+0.2) coherent polarized structure extends outside SNR to the northwest

29. a new SNR candidate in the east? G126.2+1.6 & G127.1+0.5