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2006/4/17-20 Extended 17 th SOT meeting M. Kubo (JAXA/ISAS), K. Ichimito, Y. Katsukawa (NAOJ), and SOT-team Comparison of FG and SP data from Sun test.

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Presentation on theme: "2006/4/17-20 Extended 17 th SOT meeting M. Kubo (JAXA/ISAS), K. Ichimito, Y. Katsukawa (NAOJ), and SOT-team Comparison of FG and SP data from Sun test."— Presentation transcript:

1 2006/4/17-20 Extended 17 th SOT meeting M. Kubo (JAXA/ISAS), K. Ichimito, Y. Katsukawa (NAOJ), and SOT-team Comparison of FG and SP data from Sun test

2 2006/4/17-20 Extended 17 th SOT meeting Simultaneous observation with FG and SP We simultaneously observe a sunspot with FG Shutterless IQUV and SP profiles in Sun light test at NAOJ. Filtergraph (FG Shutterless IQUV) - 2004/08/20 01:01:29 - 01:02:31UT - wavelength range: Fe I 6302.5ű240mÅ - wavelength sampling: 40mÅ step Spectro-polarimeter(SP) - 2004/08/20 00:56:19 - 01:17:46UT (20 minutes for obtaining one map) - spectral profile of Fe I 6302.5Å (and Fe I 6301.5Å ) - wavelength sampling (1pixel): 21.5mÅ FG (-240mÅ) SP (-240mÅ) 20 min Time of FG observation (13 wavelengths)

3 2006/4/17-20 Extended 17 th SOT meeting Data processing for FG and SP 1. Polarization calibration for FG and SP - X-matrices of FG and SP are presented in previous talks. - We do not calibrate polarization induced by optics outside SOT. 2. Determination of an absolute wavelength of SP profiles from the telluric line (6302.0Å) (FG wavelengths are referred to fits header values.) 3. Convolution of SP profiles with a transmission profile of FG Tunable Filter  SP profiles are modified to the profiles observed with FG. 4. Image co-alignment between FG - SP and between FG images with various wavelengths using image cross-correlation Fe I 6301.5Å telluric lines Stokes I (SP data) wavelength [pixel] (1pixel=21.5mÅ) Fe I 6302.5Å

4 2006/4/17-20 Extended 17 th SOT meeting Spatial distribution of IQUV at each wavelength 0+240-240mÅ+120-120 FG SP Stokes I At first, we compare FG IQUV images with SP maps at each wavelength same as the FG images.

5 2006/4/17-20 Extended 17 th SOT meeting Spatial distribution of IQUV at each wavelength 0+240-240mÅ+120-120 FG SP Stokes V Line center of V profile ( zero-cross ) for FG is shifted about -40mÅ to the line center of SP (absolute wavelength). Stokes V images of FG and SP have similar patterns.

6 2006/4/17-20 Extended 17 th SOT meeting Spatial distribution of IQUV at each wavelength 0+240-240mÅ+120-120 FG SP Stokes Q Stokes Q and U images of FG also have similar patterns of SP maps.

7 2006/4/17-20 Extended 17 th SOT meeting Spatial distribution of IQUV at each wavelength 0+240-240mÅ+120-120 FG SP Stokes U Stokes Q and U images of FG also have similar patterns of SP maps.

8 2006/4/17-20 Extended 17 th SOT meeting Comparison of FG and SP profiles FG (-240mÅ) SP (-240mÅ) We compare FG and SP profiles for umbra, penumbra, and quiet region. FG and SP profiles are averaged over the sky blue boxes to reduce influence on image motion due to seeing and alignment error Line centers of FG and SP are determined by second-order polynomial fitting. FG profiles are shifted to align the line centers of SP. quiet region penumbra umbra alignment result Stokes I ◇: FG - : SP Wavelength [mÅ]

9 2006/4/17-20 Extended 17 th SOT meeting FG and SP profiles (penumbra) FG and SP IQUV profiles are rough agreement as a whole, but their difference is large at some points. The difference of I is larger than Q, U, and V. This would be due to variation of light level during the observation. IQ UV ◇: shifted FG profile, -: SP profile Red : normalized by red wing Blue : normalized by blue wing

10 2006/4/17-20 Extended 17 th SOT meeting FG and SP profiles (quiet region) FG IQUV data also have similar shapes to SP profiles in the quiet region. Q, U, and V profiles of SP and FG are well fitted although degree of polarization is very small in the quiet region. IQ UV ◇: shifted FG profile, -: SP profile Red : normalized by red wing Blue : normalized by blue wing

11 2006/4/17-20 Extended 17 th SOT meeting FG and SP profiles (umbra) FG IQUV data also have similar shapes to SP profiles in the umbra. A scatter of FG data is larger than that in the penumbra or the quiet region. The umbral profiles are easy to be affected by surroundings because the umbra is darker than the surroundings. The deviation of I is large on red-side. However the absolute deviation is small, because the profiles are normalized by dark local continuum. IQ UV ◇: shifted FG profile, -: SP profile Red : normalized by red wing Blue : normalized by blue wing

12 2006/4/17-20 Extended 17 th SOT meeting Summary Stokes IQUV profiles of FG have rough agreement to SP IQUV profiles in umbra, penumbra, and quiet region. But their deviation is large at some points. The deviation of I is larger than that of Q, U, and V. The difference between FG and SP profiles would be due to - false modulation signal caused by a poor seeing condition - variation of light level seeing condition, intensity ripple of FG tunable filter (Removal of the intensity ripple were represented by Katsukawa-san.) - time difference - alignment error


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