Uvotpy

Swift UVOT grism spectral extraction code

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

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.