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Diagnostic capability of FG/SP

Diagnostic capability of FG/SP. Kiyoshi Ichimoto NAOJ. Hinode workshop , 2007.12.8-10, Beijing. Contents: Spectral windows of SOT Available spectral lines and their Zeeman properties Detection limit for the magnetic field w/ polarization sensitivity of SOT

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Diagnostic capability of FG/SP

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  1. Diagnostic capability of FG/SP Kiyoshi Ichimoto NAOJ Hinode workshop, 2007.12.8-10, Beijing

  2. Contents: • Spectral windows of SOT • Available spectral lines and their Zeeman properties • Detection limit for the magnetic field • w/ polarization sensitivity of SOT • - Retrievability of magnetic field from NFI observables

  3. Field of view 218" × 109" (full FOV) CCD 4k × 2k pixel (full FOV), shared with the NFI Spatial Sampling 0.0541 arcsec/pixel (full resolution) Spectral coverage Center (nm) Width (nm) Line of interest Purpose 388.35 0.7 CN I Magnetic network imaging 396.85 0.3 Ca II H Chromospheric heating 430.50 0.8 CH I Magnetic elements 450.45 0.4 Blue continuum Temperature 555.05 0.4 Green continuum Temperature 668.40 0.4 Red continuum Temperature Exposure time 0.03 - 0.8 sec (typical) SOT broadband filters

  4. BFI

  5. BFI

  6. BFI

  7. Contribution function of BFI continuum log(t5000)

  8. Response function of BFI intensity from DT/T courtesy Dr. Mats Carlsson

  9. CH3883, CN4305 (G-band) formation height Quiet region S. V. Berdyugina etal., 2003, A&A 412, 513–527 sunspot

  10. Field of view 328"×164" (unvignetted 264"×164") CCD 4k×2k pixel (full FOV), shared with BFI Spatial sampling 0.08 arcsec/pixel (full resolution) Spectral resolution 0.009nm (90mÅ) at 630nm Spectral windows (nm) and lines of interest Center l-range Lines geff Purpose 517.2 0.6 Mg I b 517.27 1.75 Dopplergrams and magnetograms 525.0 0.6 Fe I 524.71 2.00 Photospheric magnetograms Fe I 525.02 3.00 Fe I 525.06 1.50 557.6 0.6 Fe I 557.61 0.00 Photospheric Dopplergrams 589.6 0.6 Na I D 589.6 1.33 Very weak fields (scattering polarization)Chromospheric fields 630.0 0.6 Fe I 630.15 1.67 Photospheric magnetograms Fe I 630.25 2.50 Ti I 630.38 0.92 Umbral magnetograms 656.3 0.6 H I 656.28 ~1.3? Chromosphreic structure Exposure time 0.1 - 1.6 sec (typical) SOT narrowband filter

  11. NFI 517.27 (Mg b2)

  12. NFI 525.02

  13. NFI557.60

  14. NFI589.60 Na D1 D2 D1

  15. NFI630.25

  16. NFI656.27 Ha

  17. Zeeman patterns of NFI lines MG1 5172.680 3P1 - 3S1 2.700 -.3800WI 1259.0 b2 FE1 6302.503 5P1 - 5D0 3.686 -.6100CW 83.0 FE1 5250.207 5D0 - 7D1 .121 -4.4600CW 62.0 NA1 5895.920 2S0.5 - 2P0.5 .000 -.1840MS 564.0* H 1 6562.740 1 2S 0.5 2P 0.5 10.199 -.0606WI 4020.0

  18. Time res. # of wavelength (reliability) 1sec 64 10sec 16 1min 10min 4 2 1hr 1 1day FOV 10” 100” 1000” Spatial res. 1” 0.4” 0.2” 0.1” 1min 1% 1hr 0.1% 1day 1week 0.01% Random noise (detection limit) Time span SOT performance SOT/NFI full image Ground SP Ground FG magnetograph SOT/SP full scan Resolution for energy element　～　e (Dx)2

  19. Detection limit and accuracy of magnetic field measurements -- rough comparison with ground-based observations -- Photon noise limited, FeI6302A line SOTセミナー＠花山　2004.12.7

  20. polarimeter response matrix CCD gain/dark I’’ = a I’+b ST Incident to polarimeter Polarization modulation S Incident Stokes vector I” CCD output I’ modulated intensity Telescope ST = TS I’ = W ST on-board demodulation Sraw SOT raw data Measurement error: DS S’ SOT product S” reduced Stokes vector dark/gain correction Polarimeter response matrix X : true matrix Xr: matrix used in calibration Ground calibration Xr-1S’ S” S’ = XS X : polarimeter response matrix

  21. ＳＯＴ polarization calibration before launch 2005.6 @Mitaka Heliostat mask window (I,Q,U,V) Sheet polarizer FPP Using well-calibrated sheet polarizers (linear & circular), the polarimeter response matrices, X, of SP and all wavelength of NFI were determined with an accuracy below. Accuracy: - 0.3333 0.3333 0.2500 0.0010 0.0500 0.0067 0.0050 0.0010 0.0067 0.0500 0.0050 0.0010 0.0067 0.0067 0.0500 DX < SOT is cross-talk free at e ~ 10-3 level Diagonal elements tell about the sensitivity of the SOT to Q,U,V

  22. SP x matrices at scan center; CCD image each element is scaled to median + tolerance, x00 (=1) is replaced by I-image Median Mueller matrix Left 1.0000 0.2205 0.0187 -0.0047 0.0012 0.4813 0.0652 -0.0014 0.0001 0.0513 -0.4803 -0.0057 -0.0025 0.0032 -0.0046 0.5256 Right 1.0000 -0.2112 -0.0170 -0.0051 -0.0025 -0.4875 -0.0560 0.0022 -0.0001 -0.0426 0.4907 0.0060 0.0027 -0.0008 0.0042 -0.5301 The x matrix can be regarded as constant in the CCD.

  23. Example of FG/NFI X matrix over the CCD, 5172 80x1024 left: theta= -1.571deg. 1.0000 -0.2994 -0.0336 -0.0435 0.0009 -0.4544 0.0208 0.0045 -0.0009 0.0287 0.4478 0.0068 -0.0085 0.0318 -0.0134 0.5774 right: theta= -4.441deg. 1.0000 -0.2871 -0.0305 -0.0434 -0.0003 -0.4473 0.0653 0.0038 -0.0007 0.0738 0.4435 0.0061 -0.0077 0.0310 -0.0150 0.5718

  24. Detection limit of NFI for weak fields 1) Detection limit for circular and linear polarizations e is the photometric accuracy x33and x11 are diagonal elements of X 2) Polarization signals by Zeeman effect in a weak field Line profile convoluted with the tunable filter profile Difference of 2nd moments of s and p-components 3) Thus detection limit for magnetic fields are given by

  25. SOT modulation profiles from the measured PMU retardance 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Q V U

  26. Detection limit of FG for the weak magnetic fields, e = 0.001

  27. Choice of a NFI line

  28. How well can we retrieve the magnetic field from the products (IQUV) of the NFI? • NFI observables -- I(li), Q(li), U(li), V(li), i = 1,,, N • Physical quantities derived from the observables • -- B field strength (G), • g inclination (deg.), • c azimuth (deg), • S Doppler shift (mA) • fill factor =1 • Other quantities responsible for line formation are assumed to • be those in typical quiet sun. • An algorithm to derive the magnetic field from the NFI observables is tested. • The algorithm is based on the least square using model Stokes profiles calculated beforehand

  29. I,Q,V Zeeman profiles against B Polarization degree Vpeak （g =0゜） I Qpeak （g =90゜） Q Peak wavelength V データ解析ワークショップ　2004.12.20-23

  30. The method to derive the magnetic field vector from the NFI observables depends on the number of observed wavelength points. N = 1: 1-dimensional LUT for V/IBl, Q/I Bt individually N = 2: Rotate the frame to make U=0 (ignore MO effect) + search for the best fitting to model observable in (B, g, S) space N> 3: Initial guess with cos-fit algorithm + rotate the frame to make U~0 + search for the best fitting to model observable in (B, g, S) sub space • To test the performance of the algorithm, numerical simulations are made using ‘artificial sample observables’ (1000 sets) calculated with an atmospheric model with random physical parameters in a range of • 0 < B < 3000 G • 0 <g< 180 deg. • -90 <c< +90 deg. • -90 < S < +90 mA

  31. N = 1 at dl = -80mA, Simulation result No Doppler info. Sample observable, 1000points

  32. N = 2 at dl = [-80, 80] mA, simulation result alternative method: - ignoring MO effect - search entire (S, B, g ) space

  33. N = 4 at dl = [-110, -70, 70,110] mA, simulation result Non-uniform wavelength sampling

  34. Diagnostics using SP data slit Obtain magnetic field vectors and motions in solar atmosphere. Zeeman effect produces polarization in spectral lines

  35. Stokes profiles fitting program - Milen-Eddington fitting for Hinode SP  Data analysis session.. - SIR fitting programs SP data contains much more information on the structures of the solar atmosphere..

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