Calibration and Analysis of Ha Data to be Taken by SOT/NFI 2019-02-23 Calibration and Analysis of Ha Data to be Taken by SOT/NFI Jongchul Chae Department of Physics and Astronomy Seoul National University, Korea 2019-02-23 17th SOT meeting 17th SOT meeting

Science from Ha observations Chromosphere = a zoo of dynamic plasma features including prominences/filaments fibrils, spicules, grains surges, jets, upflow events ? Key physical processes chromospheric magnetic reconnection MHD waves Ha imaging spectroscopy 2019-02-23 17th SOT meeting

Ha absorbing/emitting features chromosphere photosphere 2019-02-23 17th SOT meeting

Contrast 2019-02-23 17th SOT meeting

Calibration Basic Processing Data Calibration Data restructuring Subtraction of dark+bias Flat fielding Data Calibration Contrast calibration Intensity calibration Wavelength calibration Data restructuring Image alignment Constructing data cube Subsonic filtering 2019-02-23 17th SOT meeting

Analysis Morphological change Brightness change Transverse velocity from tracking Cloud model analysis of contrast profile Line-of-sight velocity Optical thickness Absorption width Source function Other spectral analyses 2019-02-23 17th SOT meeting

An example: Imaging Ha spectroscopy from Ground 2019-02-23 An example: Imaging Ha spectroscopy from Ground Flat-fielding (Chae 2004, Solar Physics) Contrast & Data restructuring Cloud model fit to the contrast profile (Chae et al. 2006, Solar Physics) 2019-02-23 17th SOT meeting 17th SOT meeting

Observations 10 inch refractor at Big Bear Solar Observatory One cycle of Lyot Ha filter (0.25 A bandwidth) tuning to -0.6, -0.3, 0.0, +0.3, +0.6 A in 15 s Dalstar 1M30P Camera (12-bit, 30 fps, 20% QE, 1 pixel=0.38”). 2019-02-23 17th SOT meeting

2019-02-23 17th SOT meeting

Flat-Fielding of Solar Hα Observations Using Relatively Shifted Images (Chae 2004) 2019-02-23 17th SOT meeting

2019-02-23 17th SOT meeting

2019-02-23 17th SOT meeting

Data restructuring: Input: a sequence of two-dimensional images for each run Output: a data cube, that is, a four-dimensional array of contrast for each run 2019-02-23 17th SOT meeting

Cloud model fitting Model Inputs: Outputs: 2019-02-23 17th SOT meeting

2019-02-23 17th SOT meeting

Contrast profiles from a cube 2019-02-23 17th SOT meeting

Maps of physical parameters 2019-02-23 17th SOT meeting

Power of Ha imaging by SOT 2019-02-23 17th SOT meeting From the 1m Swedish Telescope (courtesy of O. Engvold)

Suggested SOT observing sequences 7 wavelengths at -0.9, -0.6, -0.3, 0., +0.3, +0.6, +0.9 A and a frame size of 2k by 2k. One cycling may take the duration of 33 s and the disk space of 10.5 Mb. One flat-fielding observation consists of 9 cycles with moving the telescope pointing. 2019-02-23 17th SOT meeting