An updated ultraviolet calibration for the Swift/UVOT

AA Breeveld, W Landsman, ST Holland… - AIP Conference …, 2011 - pubs.aip.org
We present an updated calibration of the Swift/UVOT broadband ultraviolet (uvw1, uvm2,
and uvw2) filters. The new calibration accounts for the∼ 1% per year decline in the UVOT
sensitivity observed in all filters, and makes use of additional calibration sources with a
wider range of colours and with HST spectrophotometry. In this paper we present the new
effective area curves and instrumental photometric zeropoints and compare with the
previous calibration.