The 2013 Flux Calibration used in uvotpy-1.0ΒΆ

The flux calibration consists of two components, the calibration of the coincidence loss and the effective area for each grism mode which is independent of the coincidence loss. The initial coincidence loss correction developed in 2012-2013 used an ad-hoc method and worked for sources up to a certain limit in brightness. The correction became uncertain when about half or more of the counts were lost due to coincidence loss. This method was implemented in the uvotpy-1.0 software, and thus is retained and the details can be consulted below.

In 2014 we succeeded in reformulating the coincidence loss and make it completely consistent with the accepted and successful theory used for point source and background. This is discussed in the current pages Coincidence loss in the UVOT and The effective area of the grisms. The new method has been implemented in the uvotpy-2.x software.

The following pages describe the details of the old calibration.