Changes between Version 35 and Version 36 of psphot_extended_source_fit
- Timestamp:
- Sep 12, 2013, 1:59:34 PM (13 years ago)
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psphot_extended_source_fit
v35 v36 25 25 These images were run though psphot using the STACKPHOT recipe. The parameters for the set of sources psphot selected for extended source fitting were 26 26 matched by coordinates to the list of simulated galaxies. In the following sections we examine the fits for the 3 different models. 27 We concentrate mostly on the simple galaxy models, pure disks (exponential profile) and and pure bulges (de Vaucouleur 1/4profile).27 We concentrate mostly on the simple galaxy models, pure disks (exponential profile) and and pure bulges (de Vaucouleur profile). 28 28 29 29 == Sersic Model == … … 45 45 46 46 === Sersic Index === 47 If we look at the sersic index for all galaxies we get the following histogram. The hisogram on the right shows the counts for pure disks and bulges. We see that the fits for bulges are clustered around 4 as expected while disks mostly have values near 1.47 If we look at the Sersic index for all galaxies we get the following histogram. The histogram on the right shows the counts for pure disks and bulges. We see that the fits for bulges are clustered around 4 as expected while disks mostly have values near 1. 48 48 49 49 [[Image(sersic_index.jpg)]] [[Image(sersic_index_pure.jpg)]] … … 51 51 === Sersic Fit Magnitudes === 52 52 53 The difference between the simulated galaxys' magnitudes and the sersic fit magnitudes are shown in the following plot. 91% of the sources are contained in the band near zero. The reason for the other bands needs to be investigated.53 The difference between the simulated galaxys' magnitudes and the Sersic fit magnitudes are shown in the following plot. 91% of the sources are contained in the band near zero. The reason for the other bands needs to be investigated. 54 54 55 55 [[Image(dmag_sersic.jpg)]] … … 59 59 [[Image(dmag_sersic_bulges.jpg)]] [[Image(dmag_sersic_disks.jpg)]] 60 60 61 The bands away from dmag == 0 are primarily objects with measured sersic index > 4.5 and small effective disk length.61 The bands away from dmag == 0 are primarily objects with measured Sersic index > 4.5 and small effective disk length. 62 62 63 63 [[Image(dmag_disks_v_dl.jpg)]] … … 66 66 67 67 ==== disks ==== 68 The models for disk galaxies are parametrized by disk scale length. The psphot extended source model width is scaled tothe half68 The models for disk galaxies are parametrized by disk scale length. The psphot extended source model width is the half 69 69 light radius. To convert from EXT_WIDTH_MAJ to scale length we must divide by 1.7. 70 70 … … 77 77 [[Image(ddl_v_mag_sersic.jpg)]] [[Image(ddl_v_dl_sersic.jpg)]] 78 78 79 and a histogram of the difference in scale length (pixels) 79 and a histogram of the difference in scale length (pixels). 80 80 81 81 [[Image(ddl_disks_hist_sersic.jpg)]] … … 105 105 }}} 106 106 107 Since all of the simulated galaxies in this sample have bulge inclination == 1 and disk inclination == 1,108 the major an minor axes should be equal and the angle will109 unmeasurable due to noise.110 107 111 108 === Exponential magnitudes === … … 157 154 [[Image(dr_v_br_dev.jpg)]] [[Image(dr_v_mag_dev.jpg)]] 158 155 156 And a histogram of the errors for pure bulges. 157 158 [[Image(dr_hist_dev.jpg)]]
