Bases: astropy.modeling.Fittable1DModel
One dimensional Sersic surface brightness profile.
Parameters: | amplitude : float
r_eff : float
n : float
|
---|---|
Other Parameters: | |
fixed : a dict
tied : dict
bounds : dict eqcons : list
ineqcons : list
|
See also
Notes
Model formula:
I(r)=I_e exp\left[-b_n\left(\frac{r}{r_{e}}\right)^{(1/n)}-1\right]
The constant b_n is defined such that r_e contains half the total luminosity, and can be solved for numerically.
\Gamma(2n) = 2\gamma (b_n,2n)
References
[R7] | http://ned.ipac.caltech.edu/level5/March05/Graham/Graham2.html |
Examples
import numpy as np
from astropy.modeling.models import Sersic1D
import matplotlib.pyplot as plt
plt.figure()
plt.subplot(111, xscale='log', yscale='log')
s1 = Sersic1D(amplitude=1, r_eff=5)
r=np.arange(0, 100, .01)
for n in range(1, 10):
s1.n = n
plt.plot(r, s1(r), color=str(float(n) / 15))
plt.axis([1e-1, 30, 1e-2, 1e3])
plt.xlabel('log Radius')
plt.ylabel('log Surface Brightness')
plt.text(.25, 1.5, 'n=1')
plt.text(.25, 300, 'n=10')
plt.xticks([])
plt.yticks([])
plt.show()
(Source code, png, hires.png, pdf)
Attributes Summary
amplitude | |
n | |
param_names | |
r_eff |
Methods Summary
evaluate(r, amplitude, r_eff, n) | One dimensional Sersic profile function. |
Attributes Documentation
Methods Documentation
One dimensional Sersic profile function.