Swift UVOT grism spectral extraction code
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The UVOTPY code provides software to extract wavelength 
and flux calibrated spectra from Swift Ultraviolet and 
Optical Grism images. The software has been tested on 
Mac and Linux.

The Swift UVOT grism calibration has been described in 

Calibration of the Swift-UVOT ultraviolet and visible grisms 
N. P. M. Kuin; W. Landsman; A. A. Breeveld; M. J. Page; H. Lamoureux; 
C. James; M. Mehdipour; M. Still; V. Yershov; P. J. Brown; M. Carter; 
K. O. Mason; T. Kennedy; F. Marshall; P. W. A. Roming; M. Siegel; 
S. Oates; P. J. Smith; M. De Pasquale
Monthly Notices of the Royal Astronomical Society 2015 449 (3): 2514-2538
doi: 10.1093/mnras/stv408

Recent calibration observations show additional loss of sensitivity below 1800A 
(that is 12 years into the mission.) Currently, 1%/year is assumed and consistent
with the red part of the spectrum. A preliminary correction for the 
UV clocked mode in the range 1700-3000A has been implemented (2017/12/30).

A (pr)eprint is also available: http://arxiv.org/abs/1501.02433

For detailed documentation including software setup, visit the grism calibration 
website available from: 

   http://www.mssl.ucl.ac.uk/www_astro/uvot/ 

In the current release of the software, the grism 
calibration files are included in the package, but 
require the definition of an environment variable, 

setenv UVOTPY <installation directory>

so that $UVOTPY/calfiles/ which contains the calibration 
files can be found by the software.

Swift UVOT readout streak photometry
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Revised modules have been included to also enable the extraction of UVOT photometry 
for brighter objects, roughly in the 12th to 9th magnitude range, using the method
described in Page, M.J.  et al. (2013) MNRAS 436, 1684. This also requires the 
Swift UVOT CALDB calibration database installed and updated. If the source 
position is given and the raw and sky files are available the result is
obtained automatically. If that is not possible, an interactive source position 
needs to be provided. 



This software is subject to a 3-clause BSD licence.  

Please reference this UVOTPY code as follows:

Kuin, N.P.M., 2014, Astrophysics Source Code Library, record ascl:1410.004.