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- Jan 25, 2019, 9:15:41 AM (7 years ago)
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trunk/doc/release.2015/ps1.analysis/analysis.tex (modified) (12 diffs)
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trunk/doc/release.2015/ps1.analysis/analysis.tex
r40609 r40610 116 116 % * real example of oversubtracted galaxy 117 117 % \end{verbatim} 118 119 \note{define psfQF, psfQFperfect}120 \note{identify when each PM\_SOURCE\_MODE bit is raised}121 \note{map PM\_SOURCE\_MODE bits from this paper to PSPS paper}122 118 123 119 The 1.8m Pan-STARRS\,1 telescope is located on the summit of Haleakala … … 543 539 {\bf Flag Name} & {\bf Flag Value} & {\bf Description} \\ 544 540 \hline 545 * PM\_SOURCE\_MODE\_PSFMODEL& 0x00000001 & Source fitted with a psf model (linear or non-linear) \\546 * PM\_SOURCE\_MODE\_EXTMODEL& 0x00000002 & Source fitted with an extended-source model \\547 * PM\_SOURCE\_MODE\_FITTED& 0x00000004 & Source fitted with non-linear model (PSF or EXT; good or bad) \\548 * PM\_SOURCE\_MODE\_FAIL& 0x00000008 & Fit (non-linear) failed (non-converge, off-edge, run to zero) \\549 * PM\_SOURCE\_MODE\_POOR& 0x00000010 & Fit succeeds, but low-SN, high-Chisq, or large (for PSF -- drop?) \\550 * PM\_SOURCE\_MODE\_PAIR& 0x00000020 & Source fitted with a double psf \\551 * PM\_SOURCE\_MODE\_PSFSTAR& 0x00000040 & Source used to define PSF model \\552 * PM\_SOURCE\_MODE\_SATSTAR& 0x00000080 & Source model peak is above saturation \\553 * PM\_SOURCE\_MODE\_BLEND& 0x00000100 & Source is a blend with other sources$^1$ \\554 * PM\_SOURCE\_MODE\_EXTERNAL& 0x00000200 & Source based on supplied input position \\555 * PM\_SOURCE\_MODE\_BADPSF& 0x00000400 & Failed to get good estimate of object's PSF \\556 * PM\_SOURCE\_MODE\_DEFECT& 0x00000800 & Source is thought to be a defect \\557 * PM\_SOURCE\_MODE\_SATURATED& 0x00001000 & Source is thought to be saturated pixels (bleed trail) \\558 *PM\_SOURCE\_MODE\_CR\_LIMIT & 0x00002000 & Source has crNsigma above limit \\559 *PM\_SOURCE\_MODE\_EXT\_LIMIT & 0x00004000 & Source has extNsigma above limit \\560 *PM\_SOURCE\_MODE\_MOMENTS\_FAILURE & 0x00008000 & could not measure the moments \\561 *PM\_SOURCE\_MODE\_SKY\_FAILURE & 0x00010000 & could not measure the local sky \\562 *PM\_SOURCE\_MODE\_SKYVAR\_FAILURE & 0x00020000 & could not measure the local sky variance \\563 xPM\_SOURCE\_MODE\_BELOW\_MOMENTS\_SN & 0x00040000 & moments not measured due to low S/N.$^1$ \\564 *PM\_SOURCE\_MODE\_BIG\_RADIUS & 0x00100000 & poor moments for small radius, try large radius \\565 *PM\_SOURCE\_MODE\_AP\_MAGS & 0x00200000 & source has an aperture magnitude \\566 *PM\_SOURCE\_MODE\_BLEND\_FIT & 0x00400000 & source was fitted as a blend \\567 *PM\_SOURCE\_MODE\_EXTENDED\_FIT & 0x00800000 & full extended fit was used \\568 *PM\_SOURCE\_MODE\_EXTENDED\_STATS & 0x01000000 & extended aperture stats calculated \\569 *PM\_SOURCE\_MODE\_LINEAR\_FIT & 0x02000000 & source fitted with the linear fit \\570 *PM\_SOURCE\_MODE\_NONLINEAR\_FIT & 0x04000000 & source fitted with the non-linear fit \\571 *PM\_SOURCE\_MODE\_RADIAL\_FLUX & 0x08000000 & radial flux measurements calculated \\572 x PM\_SOURCE\_MODE\_SIZE\_SKIPPED & 0x10000000 & size could not be determined$^2$ \\573 574 575 541 PM\_SOURCE\_MODE\_PSFMODEL & 0x00000001 & Source fitted with a psf model (linear or non-linear) \\ 542 PM\_SOURCE\_MODE\_EXTMODEL & 0x00000002 & Source fitted with an extended-source model \\ 543 PM\_SOURCE\_MODE\_FITTED & 0x00000004 & Source fitted with non-linear model (PSF or EXT; good or bad) \\ 544 PM\_SOURCE\_MODE\_FAIL & 0x00000008 & Fit (non-linear) failed (non-converge, off-edge, run to zero) \\ 545 PM\_SOURCE\_MODE\_POOR & 0x00000010 & Fit succeeds, but low-SN, high-Chisq, or large (for PSF -- drop?) \\ 546 PM\_SOURCE\_MODE\_PAIR & 0x00000020 & Source fitted with a double psf \\ 547 PM\_SOURCE\_MODE\_PSFSTAR & 0x00000040 & Source used to define PSF model \\ 548 PM\_SOURCE\_MODE\_SATSTAR & 0x00000080 & Source model peak is above saturation \\ 549 PM\_SOURCE\_MODE\_BLEND & 0x00000100 & Source is a blend with other sources$^1$ \\ 550 PM\_SOURCE\_MODE\_EXTERNAL & 0x00000200 & Source based on supplied input position \\ 551 PM\_SOURCE\_MODE\_BADPSF & 0x00000400 & Failed to get good estimate of object's PSF \\ 552 PM\_SOURCE\_MODE\_DEFECT & 0x00000800 & Source is thought to be a defect \\ 553 PM\_SOURCE\_MODE\_SATURATED & 0x00001000 & Source is thought to be saturated pixels (bleed trail) \\ 554 PM\_SOURCE\_MODE\_CR\_LIMIT & 0x00002000 & Source has crNsigma above limit \\ 555 PM\_SOURCE\_MODE\_EXT\_LIMIT & 0x00004000 & Source has extNsigma above limit \\ 556 PM\_SOURCE\_MODE\_MOMENTS\_FAILURE & 0x00008000 & could not measure the moments \\ 557 PM\_SOURCE\_MODE\_SKY\_FAILURE & 0x00010000 & could not measure the local sky \\ 558 PM\_SOURCE\_MODE\_SKYVAR\_FAILURE & 0x00020000 & could not measure the local sky variance \\ 559 PM\_SOURCE\_MODE\_BELOW\_MOMENTS\_SN & 0x00040000 & moments not measured due to low S/N.$^1$ \\ 560 PM\_SOURCE\_MODE\_BIG\_RADIUS & 0x00100000 & poor moments for small radius, try large radius \\ 561 PM\_SOURCE\_MODE\_AP\_MAGS & 0x00200000 & source has an aperture magnitude \\ 562 PM\_SOURCE\_MODE\_BLEND\_FIT & 0x00400000 & source was fitted as a blend \\ 563 PM\_SOURCE\_MODE\_EXTENDED\_FIT & 0x00800000 & full extended fit was used \\ 564 PM\_SOURCE\_MODE\_EXTENDED\_STATS & 0x01000000 & extended aperture stats calculated \\ 565 PM\_SOURCE\_MODE\_LINEAR\_FIT & 0x02000000 & source fitted with the linear fit \\ 566 PM\_SOURCE\_MODE\_NONLINEAR\_FIT & 0x04000000 & source fitted with the non-linear fit \\ 567 PM\_SOURCE\_MODE\_RADIAL\_FLUX & 0x08000000 & radial flux measurements calculated \\ 568 PM\_SOURCE\_MODE\_SIZE\_SKIPPED & 0x10000000 & size could not be determined$^1$ \\ 569 PM\_SOURCE\_MODE\_ON\_SPIKE & 0x20000000 & peak lands on diffraction spike \\ 570 PM\_SOURCE\_MODE\_ON\_GHOST & 0x40000000 & peak lands on ghost or glint \\ 571 PM\_SOURCE\_MODE\_OFF\_CHIP & 0x80000000 & peak lands off edge of chip \\ 576 572 \hline 577 \multicolumn{3}{l}{$^1$ not used for DR1 or DR2.} \\ 578 \multicolumn{3}{l}{$^2$ should not normally occur, does it?} \\ 573 \multicolumn{3}{l}{$^1$ Not used for DR1 or DR2.} \\ 579 574 \hline 580 575 \end{tabular} … … 591 586 {\bf Flag Name} & {\bf Flag Value} & {\bf Description} \\ 592 587 \hline 593 PM\_SOURCE\_MODE2\_DIFF\_WITH\_SINGLE & 0x00000001 & diff source matched to a single positive detection \\ 594 PM\_SOURCE\_MODE2\_DIFF\_WITH\_DOUBLE & 0x00000002 & diff source matched to positive detections in both images \\ 595 PM\_SOURCE\_MODE2\_MATCHED & 0x00000004 & source generated based on another image \\ 596 PM\_SOURCE\_MODE2\_ON\_SPIKE & 0x00000008 & $> 25\%$ of (PSF-weighted) pixels land on diffraction spike \\ 597 PM\_SOURCE\_MODE2\_ON\_STARCORE & 0x00000010 & $> 25\%$ of (PSF-weighted) pixels land on starcore \\ 598 PM\_SOURCE\_MODE2\_ON\_BURNTOOL & 0x00000020 & $> 25\%$ of (PSF-weighted) pixels land on burntool \\ 599 PM\_SOURCE\_MODE2\_ON\_CONVPOOR & 0x00000040 & $> 25\%$ of (PSF-weighted) pixels land on convpoor \\ 600 PM\_SOURCE\_MODE2\_PASS1\_SRC & 0x00000080 & source detected in first pass analysis \\ 601 PM\_SOURCE\_MODE2\_HAS\_BRIGHTER\_NEIGHBOR & 0x00000100 & peak is not the brightest in its footprint \\ 602 PM\_SOURCE\_MODE2\_BRIGHT\_NEIGHBOR\_1 & 0x00000200 & $flux_{\rm n} / (r^2 flux_{\rm p}) > 1$ \\ 603 PM\_SOURCE\_MODE2\_BRIGHT\_NEIGHBOR\_10 & 0x00000400 & $flux_{\rm n} / (r^2 flux_{\rm p}) > 10$ \\ 604 PM\_SOURCE\_MODE2\_DIFF\_SELF\_MATCH & 0x00000800 & positive detection match is probably this source \\ 605 PM\_SOURCE\_MODE2\_SATSTAR\_PROFILE & 0x00001000 & saturated source is modeled with a radial profile \\ 606 PM\_SOURCE\_MODE2\_ECONTOUR\_FEW\_PTS & 0x00002000 & too few points to measure the elliptical contour \\ 607 PM\_SOURCE\_MODE2\_RADBIN\_NAN\_CENTER & 0x00004000 & radial bins failed with too many NaN center bin \\ 608 PM\_SOURCE\_MODE2\_PETRO\_NAN\_CENTER & 0x00008000 & petrosian radial bins failed with too many NaN center bin \\ 609 PM\_SOURCE\_MODE2\_PETRO\_NO\_PROFILE & 0x00010000 & petrosian not build because radial bins missing \\ 610 PM\_SOURCE\_MODE2\_PETRO\_INSIG\_RATIO & 0x00020000 & insignificant measurement of petrosian ratio \\ 611 PM\_SOURCE\_MODE2\_PETRO\_RATIO\_ZEROBIN & 0x00040000 & petrosian ratio in the 0th bin (likely bad) \\ 612 PM\_SOURCE\_MODE2\_EXT\_FITS\_RUN & 0x00080000 & we attempted to run extended fits on this source \\ 613 PM\_SOURCE\_MODE2\_EXT\_FITS\_FAIL & 0x00100000 & at least one of the model fits failed \\ 614 PM\_SOURCE\_MODE2\_EXT\_FITS\_RETRY & 0x00200000 & one of the model fits was re-tried with new window \\ 615 PM\_SOURCE\_MODE2\_EXT\_FITS\_NONE & 0x00400000 & ALL of the model fits failed \\ 588 PM\_SOURCE\_MODE2\_DIFF\_WITH\_SINGLE & 0x00000001 & diff source matched to a single positive detection \\ 589 PM\_SOURCE\_MODE2\_DIFF\_WITH\_DOUBLE & 0x00000002 & diff source matched to positive detections in both images \\ 590 PM\_SOURCE\_MODE2\_MATCHED & 0x00000004 & source generated based on another image \\ 591 PM\_SOURCE\_MODE2\_ON\_SPIKE & 0x00000008 & $> 25\%$ of (PSF-weighted) pixels land on diffraction spike \\ 592 PM\_SOURCE\_MODE2\_ON\_STARCORE & 0x00000010 & $> 25\%$ of (PSF-weighted) pixels land on starcore \\ 593 PM\_SOURCE\_MODE2\_ON\_BURNTOOL & 0x00000020 & $> 25\%$ of (PSF-weighted) pixels land on burntool \\ 594 PM\_SOURCE\_MODE2\_ON\_CONVPOOR & 0x00000040 & $> 25\%$ of (PSF-weighted) pixels land on convpoor \\ 595 PM\_SOURCE\_MODE2\_PASS1\_SRC & 0x00000080 & source detected in first pass analysis \\ 596 PM\_SOURCE\_MODE2\_HAS\_BRIGHTER\_NEIGHBOR & 0x00000100 & peak is not the brightest in its footprint \\ 597 PM\_SOURCE\_MODE2\_BRIGHT\_NEIGHBOR\_1 & 0x00000200 & $flux_{\rm n} / (r^2 flux_{\rm p}) > 1$ \\ 598 PM\_SOURCE\_MODE2\_BRIGHT\_NEIGHBOR\_10 & 0x00000400 & $flux_{\rm n} / (r^2 flux_{\rm p}) > 10$ \\ 599 PM\_SOURCE\_MODE2\_DIFF\_SELF\_MATCH & 0x00000800 & positive detection match is probably this source \\ 600 PM\_SOURCE\_MODE2\_SATSTAR\_PROFILE & 0x00001000 & saturated source is modeled with a radial profile \\ 601 PM\_SOURCE\_MODE2\_ECONTOUR\_FEW\_PTS & 0x00002000 & too few points to measure the elliptical contour \\ 602 PM\_SOURCE\_MODE2\_RADBIN\_NAN\_CENTER & 0x00004000 & radial bins failed with too many NaN center bin \\ 603 PM\_SOURCE\_MODE2\_PETRO\_NAN\_CENTER & 0x00008000 & petrosian radial bins failed with too many NaN center bin$^1$ \\ 604 PM\_SOURCE\_MODE2\_PETRO\_NO\_PROFILE & 0x00010000 & petrosian not build because radial bins missing \\ 605 PM\_SOURCE\_MODE2\_PETRO\_INSIG\_RATIO & 0x00020000 & insignificant measurement of petrosian ratio \\ 606 PM\_SOURCE\_MODE2\_PETRO\_RATIO\_ZEROBIN & 0x00040000 & petrosian ratio in the 0th bin (likely bad) \\ 607 PM\_SOURCE\_MODE2\_EXT\_FITS\_RUN & 0x00080000 & we attempted to run extended fits on this source \\ 608 PM\_SOURCE\_MODE2\_EXT\_FITS\_FAIL & 0x00100000 & at least one of the model fits failed \\ 609 PM\_SOURCE\_MODE2\_EXT\_FITS\_RETRY & 0x00200000 & trailed asteroid model fit was re-tried with new window \\ 610 PM\_SOURCE\_MODE2\_EXT\_FITS\_NONE & 0x00400000 & ALL of the model fits failed \\ 611 \hline 612 \multicolumn{3}{l}{$^1$ Not used for DR1 or DR2.} \\ 616 613 \hline 617 614 \end{tabular} … … 915 912 as locally insignificant. 916 913 914 Sometimes it is useful to know if a source has a near neighbor which 915 may be affecting the photometry. Three flag bits are used to identify 916 such possible situations. Peaks which are {\em not} the brightest peak 917 within a single footprint have the flag bit 918 \code{PM_SOURCE_MODE2_HAS_BRIGHTER_NEIGHBOR} set. This is a fairly 919 common situation. We also define the following ratio to compare the 920 flux of the bright source to the flux of a neighbor scaled by 921 intervening area: $R = \frac{f_{\rm n}}{r^2 f_{\rm p}}$ where $f_{\rm 922 n}$ is the flux of the brightest neighbor in the footprint, $f_{\rm 923 p}$ is the flux of the source of interest, and $r$ is the separation 924 between the two sources. If $R > 1$, the flag bit 925 \code{PM_SOURCE_MODE2_HAS_BRIGHT_NEIGHBOR_1} is set. If $R > 10$, the flag bit 926 \code{PM_SOURCE_MODE2_HAS_BRIGHT_NEIGHBOR_10} is set. 927 917 928 \subsubsection{Centroid and Higher-Order Moments} 918 929 \label{sec:moments} … … 1420 1431 values (see Section~\ref{sec:image.preparation}). 1421 1432 1433 Several flag bits are raised based on statistics which are similar to 1434 the \code{PSF_QF} measurement. First, \ippprog{psphot} calculates the 1435 normalized, PSF-weighted fraction of pixels which are masked due to 1436 one of the following four causes: a diffraction spike (\code{SPIKE}), 1437 the core of a saturated star (\code{CORE}), burntool-subtracted region 1438 (\code{BURNTOOL}), or a pixel for which, due to interpolation or 1439 convolution, a significant fraction of the pixel flux comes from a 1440 masked pixel. These masking conditions are all treated as ``suspect'' 1441 by \ippprog{psphot}, which means they are {\em included} in the analysis of 1442 the source pixels. However, since they may potentially affect the 1443 photometry (or astrometry), it is useful to note of a source has a 1444 non-trivial fraction of these poor mask pixels. If the normalized 1445 PSF-weighted fraction of pixels masked due to any of these four 1446 conditions exceeds 25\%, then one of the following bits is raised for 1447 the corresponding condition: \code{PM_SOURCE_MODE2_ON_SPIKE}, 1448 \code{PM_SOURCE_MODE2_ON_STARCORE}, 1449 \code{PM_SOURCE_MODE2_ON_BURNTOOL}, 1450 \code{PM_SOURCE_MODE2_ON_CONVPOOR}. In addition, the following flag 1451 bits may also be raised if the central pixel 1452 of a source lands on a pixel masked for a diffraction spike 1453 (\code{PM_SOURCE_MODE_ON_SPIKE}), an optical ghost 1454 (\code{PM_SOURCE_MODE_ON_GHOST}), or off the active pixels of the CCD (\code{PM_SOURCE_MODE_OFF_CHIP}). 1455 1422 1456 \subsection{Bright Source Analysis} 1423 1457 … … 1472 1506 in the central regions are largely masked, because they are 1473 1507 saturated. Thus in these cases, the psf-weighted masked fraction (see 1474 Section~\ref{XX}) is generally quite low or 0.0. 1508 Section~\ref{sec:psf.model.choice}) is generally quite low or 0.0. 1509 Sources for which this radial profile is subtracted have the flag bit 1510 \code{PM_SOURCE_MODE2_SATSTAR_PROFILE} set. 1475 1511 1476 1512 % logRdel = 0.1 … … 1877 1913 The sources which are measured in this faint-source stage are clearly 1878 1914 low significance detections. The PV3 threshold for the bright source 1879 analysis is a signal-to-noise of 20. The lower limit cutoff for the 1880 faint source analysis in PV3 is a signal-to-noise of 5.0. Sources 1881 detected in the faint source stage are fitted with the PSF model using 1882 the linear, ensemble fitting process. 1915 analysis is a signal-to-noise of 20. The flag bit 1916 \code{PM_SOURCE_MODE2_PASS1_SRC} is raised for sources detected in 1917 this initial analysis stage. The lower limit cutoff for the faint 1918 source analysis in PV3 is a signal-to-noise of 5.0. Sources detected 1919 in the faint source stage are fitted with the PSF model using the 1920 linear, ensemble fitting process. 1921 1922 In the \ippprog{psphotStack} version of the code, the 5 filter images 1923 are processed together. In this case, any source which is detected in 1924 at least two of the five filters are then also measured on the other 1925 filter images in which it was not detected above the signal-to-noise 1926 limit. The position in the other stack images is fixed based on the 1927 pixel coordinates in the images in which the source was detected. 1928 Detection in two filters is required in order to avoid excessive 1929 forced photometry of spurious detections. There is an interesting 1930 class of astronomical objects which are extremely red (\eg, brown 1931 dwarfs and high-redshift quasars). Such sources are expected to be 1932 detected only in the reddest filter (\yps). For the $3\pi$ PV3 1933 processing, we therefore also force the photometry in all filters for 1934 sources which are only detected in \yps. All sources which are forced 1935 on one image based on detections in other images have the flag bit 1936 \code{PM_SOURCE_MODE2_MATCHED} set. 1883 1937 1884 1938 \subsection{Extended Source Analysis} … … 1987 2041 of the form $f_i(r_i)$. In this case, $f_i$ is effectively the 1988 2042 surface brightness for each radius in instrumental counts per pixel. 2043 If fewer than 4 radial surface-brightness values are available for the 2044 analysis, the source is skipped and the flag bit 2045 \code{PM_SOURCE_MODE2_ECONTOUR_FEW_PTS} is set. Some apparently 2046 extended sources are in fact bright stars with central saturation. 2047 These sources show up in this analysis as having many NAN-valued 2048 pixels in the central regions. During the radial profile analysis, 2049 such sources are flagged with the bit 2050 \code{PM_SOURCE_MODE2_RADBIN_NAN_CENTER} and are skipped from the rest 2051 of the analysis. 1989 2052 1990 2053 The surface brightness profiles are then used to define the azimuthal … … 2043 2106 max}$ for the annulus for which the Petrosian Ratio = 0.2, i.e., the 2044 2107 point on the galaxy radial profile at which the surface brightness is 2045 20\% of the average surface brightness at that point. 2108 20\% of the average surface brightness at that point. If the profile 2109 falls below the Petrosian ratio for the first radial bin, the flag bit 2110 \code{PM_SOURCE_MODE2_PETRO_RATIO_ZEROBIN} is set to note that the 2111 Petrosian radius may be poorly determined. 2046 2112 2047 2113 We determine the Petrosian Radius for the galaxy by quadratic … … 2054 2120 well as drops. We track the Petrosian Ratio until the value is no 2055 2121 longer significant ($\sigma_{\rm Ratio} < 2 {\rm Ratio}$). If the 2056 Petrosian Ratio drops below 0.2 for more than one radius, we choose 2057 the largest such radius. 2122 Petrosian ratio drops below 0.2 for more than one radius, we choose 2123 the largest such radius. If the Petrosian ratio does not fall below 2124 0.2 for any of the measured radii, the annulus for which the ratio 2125 falls to the lowest (yet still significant) value. In such a case, 2126 the flag bit \code{PM_SOURCE_MODE2_PETRO_INSIG_RATIO} is set. 2058 2127 2059 2128 Once the Petrosian Radius has been determined, we can now measure the … … 2064 2133 Petrosian flux is contained. Sources for which the Petrosian 2065 2134 parameters are successfully measured have the flag bit 2066 \code{PM_SOURCE_MODE_EXTENDED_STATS} set. 2135 \code{PM_SOURCE_MODE_EXTENDED_STATS} set. Sources for which the Petrosian 2136 parameters were attempted, but for which the radial profile analysis 2137 failed have the flag bit 2138 \code{PM_SOURCE_MODE2_PETRO_NO_PROFILE} set. 2067 2139 2068 2140 … … 2096 2168 (Section~\ref{sec:source.size}) or (b) the peak of the PSF profile was 2097 2169 above the saturation limit for the chip \citep[see the discussion 2098 in][regarding the masking of saturated pixels]{waters2017}. 2170 in][regarding the masking of saturated pixels]{waters2017}. All 2171 sources for which the extended source model fits were attempted the 2172 flag bit \code{PM_SOURCE_MODE2_EXT_FITS_RUN} set. If any of the 2173 attempted model fits failed, then the flag bit 2174 \code{PM_SOURCE_MODE2_EXT_FITS_FAIL} is set. If all model fits 2175 failed, then the flag bit \code{PM_SOURCE_MODE2_EXT_FITS_NONE} is 2176 set. 2099 2177 2100 2178 % \note{need a discussion of the detector saturation behavior?}
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