This page describes the ultraviolet version of the code. To see the optical version (HII-CHI-mistry) click here.


HII-CHI-mistry_UV is a python program that calculates for gaseous nebulae ionised by massive stars the oxygen abundance in terms of 12+log(O/H), the carbon-to-oxygen ratio as log(C/O) and the ionisation parameter, as log U, from a set of emission-line UV and optical intensities consistently with the direct method.
The methodology and the results are described in Pérez-Montero & Amorín (2017)..


Each compressed file contains the python file of the code, the libraries of the models and a file with instructions. -

 Version 3.0 (2017/09)
The errors of the intensity lines are now considered to take them into account in the calculation of the errors of the chemical abundances and log U using an iterative Monte-Carlo simulation.

- Version 2.0 (2017/01)


HII-CHI-mistry_UV has been written in python. It requires the library numpy. It also needs the files of the emission
line fluxes predicted by the models, assuming a different
set of input conditions, including:


representing the whole set of models, the models with constrained values of O/H as a function of log U, and the models with constrained values of O/H as a function of C/O, respectively.

All were calculated with Cloudy v.13 and a POPSTAR SED with an age of 1Myr and using an IMF of Chabrier.

To run the program, just type for version 3.0

> python HCm_UV_v3.0.py

The program will ask for the input file


It must be written in text format with six columns (twelve for v3.0 to include the line errors) containing in each row the fluxes in arbitrary units of the following emission linesfor single gaseous nebula or a position of it:

Lya HI 1216
CIV    1549
OIII]  1665
CIII   1909
Hb HI  4861
[OIII] 5007

all of them reddening corrected. If no information exists about a certain line it must typed as zero. Notice that contrary to
HII-CHI-mistry for the optical the lines do not have to be relative to Hbeta flux.


If the input file is correctly introduced, the program will calculate therequired quantities and their corresponding errors.
The information will be displayed in the screen for each object, along with the ratio of completeness of the task. It will be also added an index saying what grid was used, where

1: the complete grid is used (only if [OIII] 1665/5007 can be used).
2: the log U limited grid is used (when [OIII] 1665/5007 is not available)
3: the log U and C/O limited grid is used
(if, besides, CIII/OIII] cannot be obtained).

In addition the results will be saved in a file called output.dat.The first six (12 for v3.0) columns of this file will be the input emission lines and it will add the following seven columns:

grid index
error of 12+log(O/H)
log(C/O) (-10 if grid 3 is used)
error of log(N/O)
log U
error of log(U) (tak

Enrique Pérez-Montero. IAA-CSIC
Last update: 2017, September

This program has been made thanks to the financial support from Spanish AYA project Estallidos