MIPS Enhancer MIPS_Enhancer Overview MIPS Data Processing and Calibration Workshop April 12, 2004

How to Run MIPS_ENHANCER Command line options –mips_enhancer –f filename.fits (40+ options) Namelist options –mips_enhancer –n namelist.in

What have we learned since launch ? Need to make MIPS_enhancer more efficient in terms of: –Memory –Speed Improve method of combing surface bright nesses.

Memory and Speed Tiling –-x #, -y # –Only operating on tile sub-pixels Do not hold mosaic in memory –-m Memory limited to current tile Write tiles out Stitch mosaic from tiles –Necessary to change format of mosaic to limit memory needed. Primary header (history, information from first DCE) Extensions: surface brightness, uncertainty, pixel flag, overlap coverage)

Conserving Surface Brightness Improvements in: –Outlier rejection algorithm –Weighting overlapping pixels in mosaic

Outlier Rejection Algorithm For each sub- pixel there is a stack of overlapping BCD pixels.

Sub-Pixel Outlier Rejection N BCD overlapping pixel values Start Iteration i = 1. Find the median value: Median org Find Standard Deviation: STDEV org Find N differences: |(Median org – flux k )| Sort differences Withhold 10% largest differences (minimum 1) Find new median and standard deviation of remaining points: Median i, STDEV i Test Most deviant point: –(Flux most deviant point – Median i )/STDEV i > Sigma Clipping (SC) –If reject – iterate

Outlier Rejection cont. Continue iterating until: –Remain points < Minimum Points (SP) –Iteration # > Maximum # iterations (SM) –((STDEV org – STDEV new )/STDEV org )*100 > Sigma Tolerance (ST)

Variation on Outlier Rejection Option: SK Test Most deviant point: (Flux most deviant point – Median i )/STDEV i > Sigma Clipping (SC) Option: SU Instead of using the standard deviation of stack: STDEV i Combine in quadrature: uncertainty of BCD pixel and standard deviation of Median

Obsolete Outlier Rejection options Obsolete Outlier Rejection options Quartiles May retire thresholding (t) –(Flux i /Median Flux) > t continue rejecting –(Flux i /Median Flux) < t stop rejection

Conserving Surface Brightness For each sub-pixel we have N BCD pixels overlapping –Surface Brightness of BCD –Uncertainty associated with surface brightness –Overlap Area How do we combine information to conserve surface brightness in mosaic ?

Distortions

Weighting Methods Most probable value is a weighted average of points:  w i x i /  w i W 1 = overlap area, uncertainties W 2 =overlap area W 3 =overlap area, S/N (SB/uncertainty) W 4 =overlap area, SQRT(S/N) W 5 =overlap area, SQRT(S)

Useful Options for MIPS_enhancer -f filename (-i list of files) -o output_name -RR (remove rotation) -s # (scale factor, recommended = 0.25 ) dy (correct for distortion, default) -x #, -y #, -m (memory & speed options) -r # (70 microns, # BCDs to reject after stim, recommened 1) -IB (ignore bias boost, 24 microns, default) -W2 (W1,W3,W4,W5) Weight options -SC #, ST #, SP #, SM # SK, SU (outlier rejection options Recommened:SC 4, ST 10, SP 3, SM 30, SK) -FM (FD) sub-pixel flux weighted mean (median) -D, -C, -FL (sets other appropriate options)

Near Term Improvements SED mode Distortion (verify or tweak distortion coefficients produced from CODE-V) Study on surface brightness conservation –Add weighting which only uses the number of reads that went into the slope determination. –Develop testing routine to see how well we have Use simulating routine (Emeric) to add sources to cal file. Move on to 160 micron data Start enhancing framework

Suggestions ?