Edge of Cell Roll Off check

The edge rolloff was checked for a variety of science and flat field input exposures selected with observation dates after 2009-12-09. The rolloff was checked on all sides of cell xy53 on chip XY21. The main points are:

• Although all sides appear to have some degree of rolloff in the raw exposures, the flat fielding corrects the effect for the right and left sides. This is consistent with the magic results, in which the new streaks were oriented horizontally.
• The level of the rolloff scales with the background level, as can be seen in the clear ordering in the raw image profiles. This is true for both the science and flat input images.
• The rolloff on the top is generally well corrected. Two science exposures have upturns in the flat corrected profile. One has a star in the profile box (exp_name = o5180g0252o), and the other has a substantially higher background level than the others (exp_name = o5192g0138o). PNG images of these cells are at the bottom. The flat input exposure with an upturn (exp_name = o5195g0002f) does not have a significantly different background that the other flat exposures, but does show an odd defect towards the top of the cell.
• The rolloff at the bottom is the likely cause of the majority of the magic detections. The science exposures have an upturn in the bottom few rows that does not appear in the flat field exposures. This upturn carries through to the flat corrected profiles, causing a 5-10% spike for these rows.

Science exposures studied:

exp_id	exp_name	raw background level
113830	o5189g0311o	7665.45
111709	o5180g0252o	7964.01
111713	o5180g0257o	8140.44
112597	o5183g0010o	8403.45
113896	o5189g0377o	9206.13
111720	o5180g0261o	13431.88
114762	o5192g0138o	42120.74

	Raw image	Dark corrected image	Flat corrected image
Top of cell
Right of cell
Bottom of cell
Left of cell

Flat exposures studied:

exp_id	exp_name	raw background level
117099	o5197g0001f	24884.11
113067	o5187g0008f	25077.79
113522	o5189g0003f	25125.63
114670	o5192g0046f	25155.90
113974	o5190g0014f	25275.45
116145	o5195g0002f	25397.96
117941	o5199g0001f	26487.14

	Raw image	Dark corrected image	Flat corrected image
Top of cell
Right of cell
Bottom of cell
Left of cell

exp_id	exp_name	flat corrected image with regions
116145	o5195g0002f
114762	o5192g0138o
111709	o5180g0252o