= psphot Extended Source Fit 20130712 tag =

This page discusses some experiments where we ran psphot on simulated images using the current ipp tag ipp-20130712

This can be compared to the results with the ipp trunk discussed [wiki:psphot_extended_source_fit here]

The 40 simulated images were provided last year by Peter Draper for use in testing the psphot kron radius and magnitude
code. They were constructed using E Bertin's SkyMaker program. 


=== Sersic Index ===
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. 

[[Image(sersic_index_20130712.jpg)]] [[Image(sersic_index_20130712_pure.jpg)]]

=== Sersic Fit Magnitudes ===

The difference between the simulated galaxies' magnitudes and the sersic fit magnitudes are shown in the following plot. 

[[Image(dmag_sersic_20130712.jpg)]]

If we consider only the pure bulge sources the fits are better. psphot under estimates the flux somewhat. If we look at pure disks we see the banding.

[[Image(dmag_sersic_bulges_20130712.jpg)]] [[Image(dmag_sersic_disks_20130712.jpg)]]

=== Radii ===


==== disks ====
The following plot compares the measured semi-major axis with the disk scale length.

[[Image(disk_widths_20130712.jpg)]] 

==== bulges ====

Here is a comparison of the measured width to the bulge effective radius.

[[Image(bulge_widths_20130712.jpg)]] 

== Exponential Model ==

=== Exponential magnitudes ===

[[Image(dmag_exp_20130712.jpg)]] [[Image(dmag_exp_disks_20130712.jpg)]]

=== Radii ===


[[Image(disks_widths_exp_20130712.jpg)]]

== de Vaucouleurs Model ==

[[Image(dmag_dev_20130712.jpg)]] [[Image(dmag_dev_bulges_20130712.jpg)]]

[[Image(bulge_widths_dev_20130712.jpg)]]