Data Reduction Frequently Asked Questions

How can we reach tenth of a magnitude accuracy in photometry?



This new HAWK-I pipeline ( photometrically calibrates its science exposures using 2MASS stars in the field.   For 1.5 x 106 sources in all 11 HAWK-I filters, we find 81% of all matched sources have magnitudes accurate to better than 0.1 magnitudes.


Figure 1: A magnitude – Δmagnitude density plot showing the photometric quality of the HAWK-I source catalogues. The data is derived from sources in all 11 filters from reprocessed HAWK-I tiles matched with 2MASS catalogue stars. The standard deviation of the magnitude difference distribution is 0.2 magnitudes, with 80.8% of sources having  |Δm| < 0.1 magnitudes and 92.0% of sources having |Δm| < 0.2 magnitudes.