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Knowledgebase: IRAC
I need to operate with electron units on the fluxes coming from my target. How do I convert the images (in MJy/sr) to do my analysis?
Posted by Seppo Laine on 29 January 2009 12:17 PM
You need to multiply the values of the pixels by GAIN*EXPTIME/FLUXCONV to get electrons. These keywords are given in the BCD header. You should also add a term (-ZODY_EST+SKYDRKZB)/f_ext, where ZODY_EST is the estimated zodiacal background light at your observed position, found in the BCD header, and SKYDRKZB is an estimate for the zodiacal component in the skydark that was subtracted from your BCDs. f_ext is the infinite aperture correction, 0.91, 0.94, 0.71, 0.74 in channels 1-4, respectively.