.. _HeIII_fraction:

Helium doubly-ionized fraction
==============================

**Field names**: 
"HeIII_fraction", "helium_ionized_fraction", "ionized_fraction_helium", "He_ion_frac", "ion_frac_He"

**Units**: 


**Remarks**: 
volume-averaged

**Required fields**: 
"redshift"


    
Data
^^^^

.. note::
    Hover on data points to visualize their coordinates and the source. Click on a legend entry to hide it, double
    click on a legend entry to hide everything else. 

    Circles indicate measurements. Upper-/lower-pointing triangles indicate upper/lower limits.

.. raw:: html
    :file: ../plots/plots/HeIII_fraction.html


`[open plot in separate tab]`_
------------------------------

.. _[open plot in separate tab]: ../plots/HeIII_fraction.html

Data sources
^^^^^^^^^^^^

.. note::
    
    Cannot find your favorite constraint? Consider :ref:`AddYourConstraint`!

* |Makan et al. 2022|

.. |Makan et al. 2022| raw:: html

   <a href="https://ui.adsabs.harvard.edu/abs/2022ApJ...927..175M/abstract" target="_blank">Makan et al. 2022</a>

* |Worseck et al. 2016|

.. |Worseck et al. 2016| raw:: html

   <a href="https://iopscience.iop.org/article/10.3847/0004-637X/825/2/144" target="_blank">Worseck et al. 2016</a>

* |Worseck et al. 2019|

.. |Worseck et al. 2019| raw:: html

   <a href="https://iopscience.iop.org/article/10.3847/1538-4357/ab0fa1" target="_blank">Worseck et al. 2019</a>