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.