Changeset 41310 for trunk/doc/release.2015/ps1.analysis/analysis.tex
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- Mar 19, 2020, 6:20:43 AM (6 years ago)
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trunk/doc/release.2015/ps1.analysis/analysis.tex (modified) (4 diffs)
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trunk/doc/release.2015/ps1.analysis/analysis.tex
r41307 r41310 2699 2699 \label{sec:fixed.aperture.photom} 2700 2700 2701 %% some notes: 2702 %% PV3 3pi used the STACK_THREEPI recipe for ppStack 2703 %% this set (PSF.INPUT.MAX = 10.0) 2704 2701 2705 For some science goals, a well-measured color of a galaxy is more 2702 2706 important than an accurate total magnitude. In the case of PS1, the image … … 2726 2730 to smooth the model to the effective FWHM of the convolved image. The 2727 2731 entire procedure is then repeated with a target FWHM of 8 pixels 2728 (2\arcsec). 2732 (2\arcsec). \textadd{Note that we do not attempt to restrict the 2733 stack image quality to match these convolution targets. If the 2734 stack has an effective FWHM larger than either the 6 or 8 pixel 2735 targets, the convolution does not take place and the resulting 2736 analysis is performed on the raw stack. In such cases, the smallest 2737 apertures are sensitive to seeing variations and should be avoided. 2738 Of the individual images, the fraction with FWHM large than 8 2739 pixels is (\grizy) = (9.8\%, 5.1\%, 4.9\%, 3.4\%, 3.7\%), and the 2740 fraction of stacks with an effective FWHM larger than this limit will 2741 be much smaller.} 2742 2743 %% filter : fraction with FWHM < the given value: 2744 %% 2 arcsec (7.78 pix) : 10 pixels 2745 %% g : 0.902134021127 0.976721262999 2746 %% r : 0.949197642856 0.988031447337 2747 %% i : 0.950975372093 0.987227497659 2748 %% z : 0.965690586534 0.992015231573 2749 %% y : 0.963653738055 0.990022484542 2729 2750 2730 2751 For the PV3 analysis of the $3\pi$ survey data, the fluxes are … … 2740 2761 least the smallest 4 apertures. Sources for which photometry in these 2741 2762 fixed aperture are calculated have the flag bit 2742 \code{PM_SOURCE_MODE_RADIAL_FLUX} set. 2763 \code{PM_SOURCE_MODE_RADIAL_FLUX} set. \textadd{Although these aperture are 2764 chosen to match the SDSS apertures, the SDSS images are measured on 2765 unconvolved images. Since the median seeing for the SDSS images is 2766 $\sim 1.4$ arcseconds in $r$-band \citep{2007ApJS..172..634A}, our 1.5 2767 arcsecond aperture photometry should generally compare well to the 2768 SDSS aperture magnitudes.} 2769 2770 \note{test this?} 2743 2771 2744 2772 % at least out to aperture # RADIAL_AP_MIN (= 4), but no further than … … 2775 2803 aspect ratios are randomly chosen in a range from 0.25 to 1.0. The 2776 2804 position angles are set by the sequence in the image and allowed to 2777 vary from 0 to 180 degrees. The images are then convolved with a PSF 2778 model using the \code{PS1_V1} profile ($\kappa = 0.2$) and noise is 2779 added using Poisson statistics for the detected photons. 2805 vary from 0 to 180 degrees. The images are then convolved with a 2806 circular PSF model using the \code{PS1_V1} profile (\textadd{FWHM = 1.0 2807 arcseconds, }$\kappa = 0.2$) and noise is added using Poisson 2808 statistics for the detected photons. 2780 2809 2781 2810 For the figures below, we present results as a function of the (input)
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