1. Data Flow and Automatic photometry Pipeline 陳炳志 章展誥 成功大學物理系

2. Data Flow Calibration Calibration Bias Bias Dark Dark Flat Field Flat Field Automatic photometry pipeline Automatic photometry pipeline Object matching and light curve generation Object matching and light curve generation — IRAF — IDL & XMgr

3. Automatic photometry pipeline 架構在 IRAF/DAOphot package 上 (Stetson, 1987, PASP) 架構在 IRAF/DAOphot package 上 (Stetson, 1987, PASP) 減少 Coding 的時間 減少 Coding 的時間 減少犯錯的機會 減少犯錯的機會 參數越少越好 參數越少越好 減少人為判斷的錯誤或差異 減少人為判斷的錯誤或差異

4. DAOPhot (Crowd field photometry) Daofind Daofind Locate stellar-like objects in the field Locate stellar-like objects in the field Key parameters ： std. deviation of background, FWHM, detection threshold, data maximum Key parameters ： std. deviation of background, FWHM, detection threshold, data maximum Phot Phot Aperture photometry Aperture photometry Derive the magnitude as an initial value of PSF fitting Derive the magnitude as an initial value of PSF fitting Key parameters ： aperture radius, inner sky radius, annulus width of the sky, centering box size Key parameters ： aperture radius, inner sky radius, annulus width of the sky, centering box size

5. DAOPhot (Crowd field photometry) Pstselect Pstselect Select candidate PSF stars Select candidate PSF stars Key parameters: psf radius Key parameters: psf radius Criteria: recruit by the order of magnitude and no other stars or image edges falling into psf radius Criteria: recruit by the order of magnitude and no other stars or image edges falling into psf radius Psf Psf Construct analytic form of PSF Construct analytic form of PSF Key parameters: psf radius, fit radius, match radius, psf form Key parameters: psf radius, fit radius, match radius, psf form 6 analytic function form: gaussian, lorentz, moffat15, moffat25, penny1, penny2 6 analytic function form: gaussian, lorentz, moffat15, moffat25, penny1, penny2

6. DAOPhot (Crowd field photometry) Manual operation → Select/reject candidate stars recruited by pstselect Manual operation → Select/reject candidate stars recruited by pstselect Bad candidate stars often selected by pstselect Bad candidate stars often selected by pstselect Faint objects which is not detected by daofind falling into fwhm radius Faint objects which is not detected by daofind falling into fwhm radius Saturated stars or nearby objects Saturated stars or nearby objects Objects which is not saturated but become non-linear in the core region Objects which is not saturated but become non-linear in the core region Allstar Allstar Solve the stellar photometry by psf fitting Solve the stellar photometry by psf fitting Check the data quality by the subtracted image Check the data quality by the subtracted image

7. DAOPhot (Crowd field photometry) Parameters Parameters 可以分為幾類： 可以分為幾類： 與望遠鏡 /CCD 相關的參數： data maximum 與望遠鏡 /CCD 相關的參數： data maximum 和觀測環境有關參數： FWHM, sky deviation 和觀測環境有關參數： FWHM, sky deviation 可以由上面參數導出的參數： centering box size, aperture radius, inner sky radius …… 可以由上面參數導出的參數： centering box size, aperture radius, inner sky radius …… KEY PARAMETER → FWHM, sky deviation KEY PARAMETER → FWHM, sky deviation Sky deviation 可以藉由 recursive 3-σ rejection 的方 式得到 → 僅剩下 FWHM 需要量測輸入 Sky deviation 可以藉由 recursive 3-σ rejection 的方 式得到 → 僅剩下 FWHM 需要量測輸入

8. Parameters Data maximum = 50000 Data maximum = 50000 Detection threadhold = 3.5 Detection threadhold = 3.5 S=0.4246 * fwhm S=0.4246 * fwhm Centering box size = 2.0*fwhm Centering box size = 2.0*fwhm Max shift = 2.0 Max shift = 2.0 Aperture radius = 5*S Aperture radius = 5*S Inner sky radius = 6*S Inner sky radius = 6*S Annulus width of the sky: minimum 2 and consist of at least 100 pixel in the annulus Annulus width of the sky: minimum 2 and consist of at least 100 pixel in the annulus Fit radius = int(fwhm+0.75) (minimum 3) Mating radius = int(fwhm+0.75) (minimum 3) Psf radius = 4*fit radius – 1.0 (minimum 11)

9. PSF selection Construct an algorithm to perform precise candidate star recruitment before pstselect Construct an algorithm to perform precise candidate star recruitment before pstselect 1 st pass: 1 st pass: –Magnitude: brighter than a pre-calculated magnitude –Magnitude error : less than 0.1 –# of sky rejection pixel : less than 10 –Centering error : less than 1.0 pixel 2 nd pass: 2 nd pass: –Select stars from allstar output –Magnitude error : less than 0.07