Bob Carswell
Institute of Astronomy
Madingley Road
Cambridge   CB3 0HA
U.K.
 
Office: Hoyle 13

Phone:           +44.1223.337518
Switchboard: +44.1223.337548
Email:  rfc (at ast.cam.ac.uk)

The main use for this page is to provide links various versions of a Voigt profile fitting program. The code is now fairly stable, though there are probably bugs in the more obscure corners of it. The downloadable gzipped tarfile also includes another program, rdgen, which may be used to set up files for vpfit, and generally looking at spectroscopic data.

The most recent version is on Google drive, VPFIT12.4 (here as a zipped tarfile). It has passed the standard tests so should generally be OK. The direct link to the filespace on the Cambridge system no longer works, so any older versions are available only on request.

For those using Overleaf the most up-to-date version of the VPFIT documentation may be found at https://www.overleaf.com/read/vbxkcfnfgksr.

VPFIT12.3 and higher include the option to use the Kramers-Heisenberg profile which is appropriate for high very high HI column densities (it was incorrectly implemented in version 12.0). For details see Lee, Webb and Carswell, MNRAS, 449, 5555, 2020. Improvements include the implementation of a hybrid optimisation technique which is described in Webb, Carswell and Lee, MNRAS 508, 3620, 2021. Version 12.4 uses fits to the Voigt profile derivatives rather than the finite differences to estimate them in earlier versions, so should be more robust.

A somewhat dated collection of data showing the redshift evolution of the Lyman alpha forest, covering redshifts up to z=6.3.

Other links

Last update: 25 June 2024
by rfc