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Changes between Version 6 and Version 7 of fullforce_SAStest2


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Timestamp:
Mar 31, 2014, 2:11:11 PM (12 years ago)
Author:
bills
Comment:

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  • fullforce_SAStest2

    v6 v7  
    55
    66There we presented plots that send to indicate that the full force results provided a much
    7 better match to SDSS model fits than the psphotStack results for de Vaucouleurs models (dev) There was some scepticism that
     7better match to SDSS model fits than the psphotStack results for de Vaucouleurs models (dev model) There was some scepticism that
    88the difference was so great. In particular the validity of the [http://svn.pan-starrs.ifa.hawaii.edu/trac/ipp/attachment/wiki/fullforce_SAStest1/ddevrad_hist_comparison.jpg plot]
    99was doubted.
     
    1111It turns out that this scepticism was justified. The ddevrad values for the stack photometry were incorrect (the difference in units between the sdss value (arcseconds) and the IPP values (pixels) was not accounted for. Upon further review we discovered that the wrong stacks (label SAS.20130620) were used for that investigation rather than the SAS 32 stacks (label SAS.20130703).
    1212
    13 In order to examine the results in more detail we re-ran the full force pipeline on a subset of the SAS skycells, selecting only deV models for forced photometry. Recall that by default the "best" of the three models fit during stack photometry is used.  The skycells chosen were near the center
     13In order to examine the dev model results in more detail we re-ran the full force pipeline on a subset of the SAS skycells. To improve statistics we changed
     14the system to selecting only dev models for forced photometry rather than the usual method of choosing the best model. The skycells processed were near the center
    1415of the SAS field: 332 < ra < 336, -3 < dec < 3.
    1516
    16 Here is the difference between the SDSS model radius devRad_r*0.25 and the psphotStack and psphotFullForce values for EXT_WIDTH_MAJ for for dev galaxies
    17 (devFrac_r == 1.0).
     17Here are the difference between the SDSS model radius devRad_r*0.25 and the psphotStack and psphotFullForce values for EXT_WIDTH_MAJ for for dev galaxies
     18(devFrac_r == 1.0). Bright galaxies are SDSS r magnitude < 20.
    1819
    1920[[Image(ddevrad_stack.jpg)]] [[Image(ddevrad_forced.jpg)]]
     
    2324[[Image(ddevrad_comparison.jpg)]]
    2425
     26We find that the lowest chi squared fit is shifted slightly to the left indicating that we get a larger raidus. Interestingly this effect is larger for the bright objects.
     27
     28Here is the plot of the magnitude differences.
     29
     30[[Image(ddevmag.jpg)]]
     31
     32