The Neil Gehrels Swift Observatory

Known Bugs in the UVOT software

See also: UVOT Digest for discussion of open issues with UVOT software.

Swift users are encouraged to submit bug reports to swifthelp via our Feedback form, so they can be tracked and added to this list.

Priority code used in list, below: Yellow (3) = minor, Orange (2) = important, Red (1) = urgent. Green (:)) = fixed and will be available in the next build.

Date Tool Priority Symptom
2008-06-27 uvotevgrism 1 This tool is currently untested and we do not recommend using it. Instead, we advise users covert any grism event data to image files, and then run uvotimgrism.
2011-07-11 uvotdetect 1 There is a known issue in HEASOFT 6.11 that causes uvotdetect to return AB magnitudes instead of Vega magnitudes. For details on this problem, and instructions on how to fix it, please see The HEASoft Known Issues in v6.11 page in the "Swift/UVOT" section.
2007-04-26 uvotdetect 2 Current version gives unreliable results when given an exposure map. We recommend not using an exposure map when working with unsummed images. When working with summed images, we recommend setting "expopt=ALPHA".
2011-02-18 uvotimage 3 Uvotimage does not correctly set the OBS_MODE FITS keyword for settling data.
2008-06-27 uvotapercorr 3 Uvotapercorr assumes that the white PSF is the same as the B-band PSF.
2010-09-09 uvotimsum :) Old versions do not include the image binning keywords. The software defaults to the coarsest binning of the input images, but allows arbitrary binning. This has been corrected in the current version. A previous bug involving uvotsim adding two exposures that have different time frames has been fixed. As of HEASoft 6.5, uvotimsum will check that frame times match by default.
2010-09-09 uvotevtlc :) Uvotevtlc does not do aperture corrections, or large-scale sensitivity corrections when it extracts count rates from UVOT SKY images. This has been corrected in the current version of the software.
2008-06-27 uvotflatfield :) Users should use uvotlss to apply large-scale sensitivity corrections to UVOT images, not uvotflatfield.
2008-06-27 uvotmag :) Uvotmag has been depreciated. Users should use uvotflux instead.
2008-06-27 uvotexpcorr :) The functionality of this tool has been mostly superceded by routines in uvot2fits to identify and correct problems with onboard shift and add that result in lower exposure time. We recommend that this tool no longer be used.
2008-06-27 uvotexpmap :) Previous version(s) did not identify exposure time variations near the edges due to the shift and add algorithm used to correct for attitude changes. As of HEASoft 6.5 there is good support for shift and add.
2008-04-17 uvotmaghist :) The time columns (TIME and MET) in the 6.3.1 release were inadvertently changed to report the start rather than the mid-time of the exposure. As of HEASoft 6.4, they again report the mid-time of the exposure. Note that the TIMEPIXR keyword is set to 0.0 when start times are used, and to 0.5 when mid-times are used.