blackbody.py

# this file is for every temperature/redshift/blackbody related function

import numpy as np
import scipy.misc as spm

#accretion disk log temperature profile (R^{-3/4})
LOGSHIFT = 0.823959216501 # 3/4 log(3)
def disktemp(sqrR,logT0):
    # sqrR is an array of R^2
    # logT0 is log temperature (K) of accretion disk at ISCO

    A = logT0 + LOGSHIFT

    return A - 0.375 * np.log(sqrR)


#blackbody temperature (abs, not log) -> relative intensity (absolute, not log)
#T is an array of abs temperatures

def intensity(T):

    #this is basically planck's law integrated over the visible spectrum, which is assumed
    #infinitesimal. The actual constant could have been computed but it was safer
    #and faster to gnuplot-fit it with a gradient from http://www.vendian.org/mncharity/dir3/blackbody/intensity.html
    return 1./( np.exp(29622.4 / T.clip(1.)) - 1)


ramp = spm.imread('data/colourtemp.jpg')[0,:,:]/255.
rampsz = ramp.shape[0]


def colour(T):
    indices = np.clip( (T-1000)/29000. * rampsz,0.,rampsz-1.0001)

    return ramp[indices.astype(np.int),:]