<p><a href="https://academic.oup.com/mnras/article/519/3/4082/6986240" rel="nofollow noreferrer">This paper</a> describes a method to estimate the reddening of AGN using various methods, mostly to do with the intensity ratios of different absorption lines. It also mentions the Chołoniewski method, which is used to describe the luminosity function:</p>
<blockquote>
<p>Chołoniewski (1981) made the important discovery that if the
apparent brightnesses of an AGN in different passbands – for
example, the fluxes FB and FV in the Johnson B and V bands
are plotted against each other as fluxes rather than as magnitudes,
the curvature seen when plotting in magnitudes disappears.</p>
</blockquote>
<p>Reading the <a href="https://ui.adsabs.harvard.edu/abs/1981AcA....31..293C/abstract" rel="nofollow noreferrer">original paper</a> doesn't enlighten me as to what the Chołoniewski method actually is, or why it's important. Can someone please help me understand the method?</p>
<p>EDIT: it makes a lot more sense now that I'm looking at the right paper! Thanks Peter Erwin (comments).</p>

CC BY-SA 4.0
2023-02-01T20:37:31.523Z
You're looking at the wrong paper by Chołoniewski. The references to "the Chołoniewski method" in Gaskell et al. (2023) is to [Chołoniewski 1981](https://ui.adsabs.harvard.edu/abs/1981AcA....31..293C/abstract), not the 1986 paper you've linked to.
Peter Erwin
CC BY-SA 4.0
2023-02-02T03:15:59.980Z
Thanks! Edited.
Jim421616
<galaxy><magnitude><active-galaxy><flux>
What is the Chołoniewski method of estimating galaxy luminosity functions?
Jim421616
# What is the Chołoniewski method of estimating galaxy luminosity functions?

(Asked by: username_0 on 2023-01-30)

[This paper](https://academic.oup.com/mnras/article/519/3/4082/6986240) describes a method to estimate the reddening of AGN using various methods, mostly to do with the intensity ratios of different absorption lines. It also mentions the Chołoniewski method, which is used to describe the luminosity function:

> Chołoniewski (1981) made the important discovery that if the
> apparent brightnesses of an AGN in different passbands – for
> example, the fluxes FB and FV in the Johnson B and V bands
> are plotted against each other as fluxes rather than as magnitudes,
> the curvature seen when plotting in magnitudes disappears.

Reading the [original paper](https://ui.adsabs.harvard.edu/abs/1981AcA....31..293C/abstract) doesn't enlighten me as to what the Chołoniewski method actually is, or why it's important. Can someone please help me understand the method?

EDIT: it makes a lot more sense now that I'm looking at the right paper! Thanks Peter Erwin (comments).

**Tags:** galaxy, magnitude, active-galaxy, flux
> **Comments:**
> **username_1**: You're looking at the wrong paper by Chołoniewski. The references to "the Chołoniewski method" in Gaskell et al. (2023) is to [Chołoniewski 1981](https://ui.adsabs.harvard.edu/abs/1981AcA....31..293C/abstract), not the 1986 paper you've linked to.  
> **username_0**: Thanks! Edited.  

---

## 0 answers

