main.evolve

main.evolve(in_spec_elec=None, in_spec_phot=None, rate_func_N=None, rate_func_eng=None, DM_process=None, mDM=None, sigmav=None, lifetime=None, primary=None, struct_boost=None, start_rs=None, end_rs=4, helium_TLA=False, reion_switch=False, reion_rs=None, reion_method='Puchwein', heat_switch=False, DeltaT=0, alpha_bk=0.5, photoion_rate_func=None, photoheat_rate_func=None, xe_reion_func=None, init_cond=None, coarsen_factor=1, backreaction=True, compute_fs_method='no_He', mxstep=1000, rtol=0.0001, use_tqdm=True, cross_check=False)

Main function computing histories and spectra.

Parameters:

in_spec_elec : Spectrum, optional

Spectrum per injection event into electrons. in_spec_elec.rs of the Spectrum must be the initial redshift.

in_spec_phot : Spectrum, optional

Spectrum per injection event into photons. in_spec_phot.rs of the Spectrum must be the initial redshift.

rate_func_N : function, optional

Function returning number of injection events per volume per time, with redshift \((1+z)\) as an input.

rate_func_eng : function, optional

Function returning energy injected per volume per time, with redshift \((1+z)\) as an input.

DM_process : {‘swave’, ‘decay’}, optional

Dark matter process to use.

sigmav : float, optional

Thermally averaged cross section for dark matter annihilation.

lifetime : float, optional

Decay lifetime for dark matter decay.

primary : string, optional

Primary channel of annihilation/decay. See get_pppc_spec() for complete list. Use ‘elec_delta’ or ‘phot_delta’ for delta function injections of a pair of photons/an electron-positron pair.

struct_boost : function, optional

Energy injection boost factor due to structure formation.

start_rs : float, optional

Starting redshift \((1+z)\) to evolve from. Default is \((1+z)\) = 3000. Specify only for use with DM_process. Otherwise, initialize in_spec_elec.rs and/or in_spec_phot.rs directly.

end_rs : float, optional

Final redshift \((1+z)\) to evolve to. Default is 1+z = 4.

reion_switch : bool

Reionization model included if True, default is False.

helium_TLA : bool

If True, the TLA is solved with helium. Default is False.

reion_rs : float, optional

Redshift \((1+z)\) at which reionization effects turn on.

photoion_rate_func : tuple of functions, optional

Functions take redshift \(1+z\) as input, return the photoionization rate in s^-1 of HI, HeI and HeII respectively. If not specified, defaults to photoion_rate().

photoheat_rate_func : tuple of functions, optional

Functions take redshift \(1+z\) as input, return the photoheating rate in s^-1 of HI, HeI and HeII respectively. If not specified, defaults to photoheat_rate().

xe_reion_func : function, optional

Specifies a fixed ionization history after reion_rs.

init_cond : tuple of floats

Specifies the initial (xH, xHe, Tm). Defaults to Tm_std(), xHII_std() and xHeII_std() at the start_rs.

coarsen_factor : int

Coarsening to apply to the transfer function matrix. Default is 1.

backreaction : bool

If False, uses the baseline TLA solution to calculate \(f_c(z)\). Default is True.

compute_fs_method : {‘no_He’, ‘He_recomb’, ‘He’, ‘HeII’}

Method for evaluating helium ionization.

• ‘no_He’ – all ionization assigned to hydrogen;
• ‘He_recomb’ – all photoionized helium atoms recombine; and
• ‘He’ – all photoionized helium atoms do not recombine;
• ‘HeII’ – all ionization assigned to HeII.

Default is ‘no_He’.

mxstep : int, optional

The maximum number of steps allowed for each integration point. See scipy.integrate.odeint() for more information. Default is 1000.

rtol : float, optional

The relative error of the solution. See scipy.integrate.odeint() for more information. Default is 1e-4.

use_tqdm : bool, optional

Uses tqdm if True. Default is True.

cross_check : bool, optional

If True, compare against 1604.02457 by using original MEDEA files, turning off partial binning, etc. Default is False.

See also

get_pppc_spec(), struct_boost_func(), photoion_rate(), photoheat_rate(), Tm_std(), xHII_std()

Examples

1. Dark matter annihilation – dark matter mass of 50 GeV, annihilation cross section \(2 \times 10^{-26}\) cm³ s^-1, annihilating to \(b \bar{b}\), solved without backreaction, a coarsening factor of 32 and the default structure formation boost:

   import darkhistory.physics as phys
   
   out = evolve(
       DM_process='swave', mDM=50e9, sigmav=2e-26, 
       primary='b', start_rs=3000., 
       backreaction=False,
       struct_boost=phys.struct_boost_func()
   )
   

2. Dark matter decay – dark matter mass of 100 GeV, decay lifetime \(3 \times 10^{25}\) s, decaying to a pair of \(e^+e^-\), solved with backreaction, a coarsening factor of 16:

   out = evolve(
       DM_process='decay', mDM=1e8, lifetime=3e25,
       primary='elec_delta', start_rs=3000.,
       backreaction=True
   )