Primary results of polarization survey of large-SNRs at 6cm Li Xiao, XiaoHui Sun, Chen Wang, WeiBin...
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Transcript of Primary results of polarization survey of large-SNRs at 6cm Li Xiao, XiaoHui Sun, Chen Wang, WeiBin...
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
outlines
• System parameter of Urumqi 25m telescope
• How we choose the observation target?
• The large-SNRs observation list
• preliminary results
• The future work
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%
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)
the large-SNRs observation listName 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+0.6 90*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*4.2 4• G89.0+4.7(HB21) 120*90 3*3 6• G93.7-0.2(CTB104A, DA551) 80 3*3 6• G114.3+0.3 90*55 3*3 4• G116.5+1.1 80*60 3*3 4• G119.5+10.2(CTA1) 90 3*3 7• G126.2+1.6 & G127.1+0.5 70 4*4 4• G132.7+1.3(HB3) 80 5*5 4• G156.2+5.7 110 3*3 8• G160.9+2.6(HB9) 140*120 4*4 6• G166.2+2.5OA184 90*70 5*5 4• G180-1.7(S147) 180 5*5 2• G205.5+0.5 220 5*5 0
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)
• Previous Observations:– Radio: the remnant locates in the Cygnus X complex. It displays a no
n-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
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)
• 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;
ROSAT image
(leahy et al. 1996)11cm
(haslam et al. 1975)35cm
(Reich et al. 2003)
408Mhz(Tatematsu et al. 1990)
• Previous Observations:– Radio: large, filamentary shell; Pulsar within boundary of the remnan
t, 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
4.7Ghz(leahy et al. 1998)
863Mhz(Reich et al. 2003) 151Mhz
(leahy et al. 1998)
ROSAT image(leahy et al. 1995)
• Previous Observations:– Radio: faint shell, distorted with many protrusions, radio source in no
rth 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
2.7Ghz(Velusamy & Kundu 1974)
1.7Ghz(Mantovani et al. 1982)
4.75Ghz(Mantovani et al. 1991)
1.4Ghz408Mhz
• Previous Observations:– Radio: shell, with HII region S165 within the boundary of the remnan
t. 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
• Previous Observations:– Radio: G116.5+1.1 distinct shell, with high polarization. CTB1 incompl
ete 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
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
• 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
408Mhz
(Joncas et al. 1989) 863Mhz 1.4Ghz
2.7Ghz(furst et al. 1983)
4.8Ghz(furst et al. 1984)
G127.1+0.5
• Previous Observations:– Radio: incomplete shell; typical structure of breakout; compact, centr
al 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
1.4Ghz (image) + ROSAT (contours)
1.7Ghz(Sieber et al. 1981)
2.7Ghz(Sieber et al. 1981)
151Mhz(Sieber et al. 1981)
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
• 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
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