Index: trunk/doc/release.2015/ps1.analysis/analysis.tex =================================================================== --- trunk/doc/release.2015/ps1.analysis/analysis.tex (revision 40591) +++ trunk/doc/release.2015/ps1.analysis/analysis.tex (revision 40592) @@ -623,5 +623,5 @@ \label{sec:peaks} -\note{add a ref to the Kaiser paper} +%% is there a ref I can use for the optimal detection? see SDSS docs? The sources are initially detected by finding the location of local @@ -1276,4 +1276,5 @@ \subsubsection{Radial Profile Wings} +\label{sec:radial.profile} We attempt to measure the radial profile of sources in order to find @@ -1335,5 +1336,5 @@ neighbors. -\note{give a test example} +% \note{give a test example} \subsubsection{Source Size Assessment} @@ -1379,6 +1380,4 @@ \subsubsection{Full PSF Model Fitting} - -% \note{review the discussion below} % gaussSigma = MOMENTS_GAUSS_SIGMA from recipe (initially) @@ -1609,6 +1608,5 @@ %% In order for a source to be included in the extended source %% analysis, it much have been detected in the 'bright source' analysis -%% step ($S/N > 20$, Section~\ref{sec:xxxx}). \note{is this restriction -%% more or less severe than the mag limits?} +%% step ($S/N > 20$, Section~\ref{sec:xxxx}). The extended source analysis is not applied to all object which may be @@ -1800,7 +1798,5 @@ in][regarding the masking of saturated pixels]{waters2017}. -% \note{need a discussion of the detector saturation behavior - -% \note{more detail below?} +% \note{need a discussion of the detector saturation behavior?} Before the non-linear fitting may be performed, it is necessary to @@ -1899,5 +1895,5 @@ using an FFT-based convolution. -\note{examples? show timing comparisons?} +% \note{examples? show timing comparisons?} For the Exponential and DeVaucouleur fits, all parameters are fitted @@ -1978,36 +1974,41 @@ minimize the impact of the stack image quality variations. -In \code{psphotStack}, the stack analysis version of \code{psphot}, the 5 filter -images are processed together. After the PSF models have been fitted -and a best set of galaxy models have been determined, three sets of -radial apertures are measured. In the first set, the fluxes in the -radial apertures are measured using the raw stack images. The centers -of the apertures for each source across the 5 filters are fixed so -that the pixels represent the equivalent portions of the same galaxy -for all 5 filters. In this analysis, the best model for each source -is subtracted from the image pixels for all sources excluding the -source in consideration. The 'best model' is determined based on the -minimum $\chi^2$ value for the model fits. +In \code{psphotStack}, the stack analysis version of \code{psphot}, +the 5 filter images are processed together. After the PSF models have +been fitted and a best set of galaxy models have been determined, +three sets of fixed circular apertures are measured. In the first +set, the fluxes in the apertures are measured using the raw stack +images. The centers of the apertures for each source across the 5 +filters are fixed so that the pixels represent the equivalent portions +of the same galaxy for all 5 filters. In this analysis, the best +model for each source is subtracted from the image pixels for all +sources excluding the source in consideration. The 'best model' is +determined based on the minimum $\chi^2$ value for the model fits. + +In addition to the raw fixed circular apertures, the stack images are +each convolved with a circular Gaussian with $\sigma$ chosen to yield +an image with a typical FWHM of 6 pixels (1.5\arcsec). The full set +of circular apertures are again measured on these convolved images. +Again, the best source models are subtracted from the image for +sources not being measured. This subtraction includes the convolution +to smooth the model to the effective FWHM of the convolved image. The +entire procedure is then repeated with a target FWHM of 8 pixels +(2\arcsec). For the PV3 analysis of the $3\pi$ survey data, the fluxes are -measured for a set of 9 circular apertures with sizes chosen to match -the similar circular apertures measured by the SDSS analysis. are measured +measured for a set of up to 9 circular apertures with sizes chosen to +match the similar circular apertures measured by the SDSS analysis. +These apertures have radii of (4.16, 7.04, 12.0, 18.56, 29.76, 45.68, +72.80, 112.80, 176.88) pixels = (1.04, 1.76, 3.00, 4.64, 7.44, 11.42, +18.20, 28.20, 44.22) arcseconds. If the object is too faint, the +larger apertures will be largely noise and the computation is +wasteful. We only calculate the circular apertures out to the second +aperture larger than the ``sky radius'' (defined in +Section~\label{sec:radial.profile}), but we calculate photometry for +at least the smallest 4 apertures. % at least out to aperture # RADIAL_AP_MIN (= 4), but no further than % the aperture with radius > skyRadius % last bin is first with inner radius >= skyRadius - -% \note{more discussion of the selection of the best model}. - -In addition to the raw radial apertures, the stack images are each -convolved with a circular Gaussian with $\sigma$ chosen to yield an -image with a typical FWHM of 6\arcsec. The full set of radial -apertures are again measured on these convolved images. Again, the -best source models are subtracted from the image for sources not being -measured. This subtraction includes the convolution to smooth the -model to the effective FWHM of the convolved image. The entire -procedure is then repeated with a target FWHM of 8\arcsec. - -% \note{is the first convolution done with the Alard-Lupton technique?} \subsection{Aperture Correction and Total Aperture Fluxes} @@ -2186,5 +2187,5 @@ \end{table*} -\subsection{Output Formats} +% \subsection{Output Formats} \section{Forced Photometry Modes} @@ -2370,5 +2371,5 @@ types of sources. This model is fitted in the same portion of the code which performs the unconvolved galaxy model analysis. -\note{describe the trailed analytical model}. +% \note{describe the trailed analytical model}. In some cases, the stars in the two images may be somewhat offset. @@ -2381,10 +2382,50 @@ negative images will have stellar profiles, but they will be offset and will not subtract well. The two components may not have the same -amplitude. In theory, a PSF-dipole model could be used to fit these types of -sources, with free parameters of the two centroids and the two -fluxes. In practice in \ippprog{psphot}, we use a number of non-parametric -pixel-level statistics in an attempt to detect these cases. - -\note{list the parameters} +amplitude. In theory, a PSF-dipole model could be used to fit these +types of sources, with free parameters of the two centroids and the +two fluxes. In practice in \ippprog{psphot}, we use a number of +non-parametric pixel-level statistics in an attempt to detect these +cases. + +For the difference images, we measure the following quantities for +each of the detections, using only pixels within the photometry +aperture. First, we count the number of masked pixels (\code{nMask}), +the number of pixels with positive flux (\code{nGood}), and the number +of pixels with negative flux (\code{nBad}). We also add the total +flux in positive pixels (\code{fGood}) and total absolute value of the +flux in negative pixels (\code{fBad}). Using these values, We report +the following quantities: +\begin{itemize} +\item \code{nGood} +\item \code{fRatio} = \code{fGood} / (\code{fGood} + \code{fBad}) +\item \code{nRatioBad} = \code{nGood} / (\code{nGood} + \code{nBad}) +\item \code{nRatioMask} = \code{nGood} / (\code{nGood} + \code{nMask}) +\item \code{nRatioAll} = \code{nGood} / (\code{nGood} + \code{nMask} + \code{nBad}) +\end{itemize} + +We also attempt to place the difference image detections in the +context of the input images, both the positive (subtrahend) and +negative (minuend) images. We identify the closest source in both the +postive and negative images to the detection in the difference image, +out to a maximum of \code{INPUT.MATCH.RADIUS} (= 50 pixels), but only +if the source in those images has a signal-to-noise greater than +\code{INPUT.MATCH.MIN.SN} (= 10). If there is a close neighbor in the +positive image, and the difference in the magnitudes of the source in +that image and the source in the difference image is less than 5 +$\sigma$, then the bit \code{PM_SOURCE_MODE2_DIFF_SELF_MATCH = + 0x00000800} is raised in \code{mask2} as these two detections are +likely the same flux (\ie, detection of an isolated source). + +If the difference image detection is matched to a nearby source in the +positive image, then the signal-to-noise of the neighbor is saved as +\code{DIFF_SN_P} and the distance in pixels between the difference +detection and positive detection is saved as \code{DIFF_R_P}. +Similarly, for a neighbor in the negative image, these values are +saved as \code{DIFF_SN_M} and \code{DIFF_R_M}. Additional +\code{mask2} bits are also raised: if the difference detection is only +associated with one of the two input images, then the bit +\code{PM_SOURCE_MODE2_DIFF_WITH_SINGLE = 0x00000001} is raised, while +a difference detection which has a match in both input images has +\code{PM_SOURCE_MODE2_DIFF_WITH_DOUBLE = 0x00000002} raised. Comets appear in the difference images as a non-PSF sources. Their @@ -2436,10 +2477,4 @@ \end{document} -\subsection{Output Options} - -% \note{need to discuss tests} - -% \note{need to discuss failings and holes} - \begin{verbatim} Configuration variables affecting the peak detection process: