Swift Diffuse Light

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1 Diffuse Background with Swift

[edit] Diffuse Background with Swift

[edit] Overview

Information about the Swift mission can be found here [[1]].

[edit] Filters

The filters used for our diffuse background work are

Useful filters for diffuse work
Filter Name	Filter Band	Calibration for diffuse sources	Dark Count (photon units)
U	3450	$4.76 \pm 1.93 \times 10^{6}$	$333 \pm 19$
B	4350	$5.31 \pm 0.578 \times 10^{6}$	$371 \pm 21.2$
V	5460	$1.13 \pm 0.06 \times 10^{7}$	$791 \pm 45.2$
UVM2	2200	$1.41 \pm 0.197 \times 10^{7}$	$987 \pm 56.4$
UVW2	1930	$1.08 \pm 0.0755 \times 10^{7}$	$756 \pm 43.2$
UVW1	2600	$8.50 \pm 0.167 \times 10^{6}$	$600 \pm 34.3$

[edit] Dark Count

The estimated dark rate is measured to be $7 \pm 0.4 \times 10^{-5} cts/pixel/s$ in orbit.

[edit] Data Format

There are several data products available from the Swift archives. We begin with the reduced data in sky units *sk.img. These are in units of counts/pixel/s and are FITS iamge format with each HDU having different exposure times and possibly slightly different pointings.

[edit] What needs to be done

Much of the image analysis will follow the GALEX data analysis (see Wiki page). Here is a step by step procedure:

Add together all the different extensions for a given observation.

Find and blank out point sources (stars).

Smooth over remainder of field.

Compare to other filters.

Compare to IR observations.

[edit] Specific Observations

[edit] 020037

Observations of GRB 060319 in the constellation of Draco through the UW2 filter. There is nothing exciting around here. The values are between 0.0003 and 0.0008 which works out to 3240 - 8640 photon units. Of this, 756 is dark count.

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