# potfile

Under this identifier are defined the default parameters for all the galaxy scale mass components that account for perturbations to the cluster potential by the galaxies. By default, the mass distribution model for the galaxies is [PIEMD]().



## filein int filename
[//]: {#filein-potfile}

If `int = 1` or `3` the galaxy catalog format is $\rm (id\, x_c \,y_c \,a \,b\, \theta\, mag\, lum)$.
If `int = 3`, $x_c$ and $y_c$ are given in degrees in the equatorial coordinates.
If `int = 1`, $x_c$ and $y_c$ are given in arcseconds relative to the reference point given in the [runmode]() section. 
Note that the keyword `#REFERENCE` in the header of the catalog overrides this behavior in all cases.

If `int = 2`, the galaxy catalog format is $\rm (ftype\, x_c\, y_c\, \epsilon\, \theta\, r_{core}(kpc)\, r_{cut}(kpc)\, \sigma(km/s)\, z)$.

The [ellipticity]() $\epsilon$ parameter is linked to $a$ and $b$ by : $\epsilon = (a^2-b^2)/(a ^2 +b ^2)$ . The ellipticity ε of the galaxies is then computed again according to their potential type ([type]).



## type int

All the galaxies have the same mass profile set by `int`. Default value is `81`, i.e. [PIEMD]() potential. 
In the current version, the last column in the catalog (Luminosity) is not used. The dynamical parameters $(r_{core},\, r_{cut},\,\sigma)$ of the potfile galaxies are scaled with the scaling relations described below.


## mag0 float

`float` is the $m^*$ parameter of the reference galaxy for the scaling relations below. It can be in absolute or in relative magnitudes according to the magnitude you give in your potfile. $m^*$ default value is 17 mag.

## zlens float

All the galaxies with no specified redshift (Catalog format 3) have the same redshift `float`. This is used to compute the  diameter angular distance.



## sigma int float1 float2


float1 is $\sigma^*$  in km/s. The velocity dispersion of the galaxies is given by $\sigma = \sigma^*\, \left( \frac{L}{L^*} \right)^{\frac{1}{\rm vdslope}}$

In the inverse 3 bayesian optimisation method, int can be either 1 or 3 for the uniform or Gaussian prior respectively. 
If `int = 1`, `float1` and `float2` are the min and max limits respectively. 
If `int = 3`, `float1` and `float2` are the mean and stddev parameters of the Gaussian pdf. 

In the inverse 2 optimisation mode (deprecated), int sets the number of bins for the potfile optimisation in the range (min,max) = (float1, float2).

## core float

float is $r_c^*$ in arc seconds. It is used to compute the core radius of the galaxies using the scaling relation $r_c= r_c^*\ \left( \frac{L}{L^{\star}} \right)^{\frac{1}{2}}$. 

## corekpc float

`float` is $r_c$ in kpc. It is used to compute the core radius in kpc of the galaxies. The cosmological parameters defined in the [cosmologie]() Section are used to convert from kpc to arc seconds. [core]() parameter defined in arc second takes precedence over [corekpc]().
$$
r_{core} {\rm ('') \ } = \frac{1}{D_{OL}} \frac{c}{H_0} r_{core} \rm(kpc) 
$$

## cut int float1 float2
 
`float1` is $r_{\rm cut}^{\star}$ in arc seconds. The cut radius in arc seconds of a galaxy is $r_{\rm cut} = r_{\rm cut}^{\star} 10^{ 0.4 \frac{2 (m_{\star} - mag)}{\rm slope} } = r_{\rm cut}^{\star} \left( \frac{L}{L^{\star}} \right)^{\frac{2}{\rm slope}}$.

`int` and `float2` are used for the potfile optimisation. (see [sigma]() keyword and [inverse]() section).

## cutkpc int float1 float2

`float1` is $r_{cut}^{\star}$ in kpc and is used to compute the cut radius of the galaxies in kpc. The cosmological parameters defined in the [`cosmologie`]() section are then used to convert from kpc to arc seconds. Arguments `int`, `float1` and `float2` work in the same way as for the [`cut`]() parameter. [`cut`]() parameter defined in arc second takes precedence over [`cutkpc`]().

## slope int float1 float2

`float1` is the slope value used in the cut radius computation. int and float2 are used in the potfile optimisation.  Slope default value is 4, i.e. a constant M/L ratio. To reproduce the fundamental plane, you need to set slope to 2.5.

## vdslope int float1 float2

`float1` is the velocity dispersion slope value used in the σ computation (see [sigma]() parameter). `int` and `float2` are used in the potfile optimisation. vdslope default value is 4.