Asada24

class eazy.igm.Asada24(sigmoid_params=(3.5918, 1.8414, 18.001), scale_tau=1.0, add_cgm=True, **kwargs)

Bases: object

Compute IGM+CGM transmission from Asada et al. 2024, in prep. The IGM model is from Inoue+ (2014).

Parameters:

sigmoid_params3-tuple of float

Parameters that controll the redshift evolution of the CGM HI gas column density. The defaul values are from Asada et al. (2024).

scale_taufloat

Scalar multiplied to tau_igm

add_cgmbool

Add the additional LyA damping absorption at z>6 as described in Asada+24. If False, the transmission will be identical to Inoue+2014

.. plot::

include-source:

# Compare two IGM transmissions

import numpy as np import matplotlib.pyplot as plt from eazy import igm as igm_module

igm_A24 = igm_module.Asada24() igm_I14 = igm_module.Inoue14()

redshifts = [6., 7., 8., 9., 10.] colors = [‘b’, ‘c’, ‘purple’, ‘orange’, ‘red’]

wave = np.linspace(100,2000,1901) ## wavelength array in the rest-frame lyman = wave < 2000

fig = plt.figure(figsize=(6,5)) for z, c in zip(redshifts, colors):

igmz_A24 = wave*0.+1 igmz_A24[lyman] = igm_A24.full_IGM(z, (wave*(1+z))[lyman])

igmz_I14 = wave*0.+1 igmz_I14[lyman] = igm_I14.full_IGM(z, (wave*(1+z))[lyman])

plt.plot(wave*(1+z), igmz_I14, color=c, ls=’dashed’) plt.plot(wave*(1+z), igmz_A24, color=c, label=r’$z={}$’.format(int(z)))

plt.xlabel(‘Observed wavelength [A]’) plt.ylabel(‘Transmission’)

plt.legend()

plt.xlim(5000,17000)

Attributes Summary

NA	Number of Lyman-series lines
max_fuv_wave	Maximum FUV wavelength (Angstroms) where IGM model will have an effect

Methods Summary

full_IGM(z, lobs)	Get full IGM+CGM absorption
lgNHI_z(z)	HI column density as a function of redshift, calibrated in Asada+ 2024.
tLCDLA(zS, lobs)	Lyman continuum, DLA
tLCLAF(zS, lobs)	Lyman continuum, LAF
tLSDLA(zS, lobs)	Lyman Series, DLA
tLSLAF(zS, lobs)	Lyman series, Lyman-alpha forest
tau_cgm(N_HI, lam, z)	CGM optical depth given by Totani+06, eqn (1)

Attributes Documentation

NA

Number of Lyman-series lines

max_fuv_wave

Maximum FUV wavelength (Angstroms) where IGM model will have an effect

Methods Documentation

full_IGM(z, lobs)

Get full IGM+CGM absorption

Parameters:

zfloat

Redshift to evaluate IGM absorption

lobsarray-like

Observed-frame wavelength(s) in Angstroms.

Returns:

absarray-like

IGM+CGM transmission factor

lgNHI_z(z)

HI column density as a function of redshift, calibrated in Asada+ 2024. Only valid at z>=6

Parameters:

zfloat

Redshift of the source

Returns:

log10(HI column density [cm-2])

tLCDLA(zS, lobs)

Lyman continuum, DLA

tLCLAF(zS, lobs)

Lyman continuum, LAF

tLSDLA(zS, lobs)

Lyman Series, DLA

tLSLAF(zS, lobs)

Lyman series, Lyman-alpha forest

tau_cgm(N_HI, lam, z)

CGM optical depth given by Totani+06, eqn (1)

Parameters:

N_HIfloat

HI column density [cm-2]

lam1D array

wavelength array in the observed frame [AA]

zfloat

Redshift of the source

Returns:

1D array of tau_CGM