mgcamb¶
Modified Gravity Boltzmann and background integrator for BG, CMB, and matter power
File |
boltzmann/mgcamb/camb.so |
Attribution |
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G.B. Zhao |
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Antony Lewis |
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Anthony Challinor |
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URL |
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Citations |
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See the CAMB module for a general introduction to CAMB.
MGCAMB is a modified version of CAMB in which the linearized Einstein equations of General Relativity (GR) are modified.
It implements several different parameterizations, which are described on this page: http://www.sfu.ca/~aha25/Models.html and referred to here as:
model 0 : default GR
model 1 : BZ(mu,gamma) ( introduced in arXiv:0801.2431)
model 2 : (Q,R) ( introduced in arXiv:1002.4197 )
model 3 : (Q0,R0,s)( introduced in arXiv:1002.4197 )
model 4 : f(R) ( introduced in arXiv:0909.2045 )
model 5 : Chameleon ( introduced in arXiv:0909.2045 )
model 6 : Linder’s gamma (introduced in arXiv:0507263 )
Assumptions¶
One of several modification ansatzes specifying changes from GR
wCDM background evolution
Other camb assumptions
Setup Parameters¶
Name |
Type |
Default |
Description |
---|---|---|---|
mode |
str |
Choose from Background, thermal, cmb, or all. In background mode only the expansion history is calculated. In thermal mode the recombination history is computed and rs_zdrag and related quantities also. In cmb mode the CMB power spectra are also calculated. In all mode the matter power spectrum at low redshift and sigma8 are also calculated. |
|
mg_model |
int |
From 0-6, choice of MG model to use |
|
lmax |
int |
Only if mode!=background, default 1200 - the max ell to use for cmb calculation |
|
feedback |
int |
Amount of output to print. 0 for no feedback. 1 for basic, 2 for extended. |
|
use_tabulated_w |
bool |
False |
Set to true to load w(z) from previous module |
k_eta_max_scalar |
int |
Maximum value of (k eta) to evolve for scalars. (default 2*lmax) |
|
do_tensors |
bool |
False |
Include tensor modes |
zmin |
real |
0.0 |
Min value to save P(k,z) |
zmax |
real |
4.0 |
Max value to save P(k,z) |
nz |
int |
401 |
Number of z values to save P(k,z) (default gives dz=0.01) |
do_nonlinear |
bool |
False |
Apply non-linear halofit corrections to matter-power. Relevant only for lensing right now |
do_lensing |
bool |
False |
Include lensing of CMB, and save C_ell phi-phi |
high_ell_template |
str |
Required for lensing - set to the file included in the camb dir |
Input values¶
Section |
Name |
Type |
Default |
Description |
---|---|---|---|---|
modified_gravity |
grtrans |
real |
Scale factor of transition from GR |
|
b1 |
real |
Model 1, beta 1 in mu(a,k) |
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b2 |
real |
Model 1, beta 2 in gamma(a,k) |
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lambda1_2 |
real |
Model 1, lambda_1^2 in mu(a,k) |
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lambda2_2 |
real |
Model 1, lambda_2^2 in gamma(a,k) |
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ss |
real |
Model 1, scale factor power index in mu and gamma |
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MGQfix |
real |
Model 2, Constant Q value |
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MGRfix |
real |
Model 2, Constant R value |
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Qnot |
real |
Model 3, Q_0 term in Q(k,a) |
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Rnot |
real |
Model 3, R_0 term in R(k,a) |
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sss |
real |
Model 3, scale factor power index for Q and R |
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b0 |
real |
Models 4 & 5, B_0 term that goes into lambda_1^2 in mu(a,k) |
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beta1 |
real |
Model 5, beta_1 term that goes into lambda_2^2 term in mu(a,k) |
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s |
real |
Model 5 scale factor power index for mu |
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linder_gamma |
real |
Model 6, gamma_L power law in Omega_M for growth rate |
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cosmological_parameters |
omega_b |
real |
Baryon density fraction today |
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omega_c |
real |
CDM density fraction today |
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omega_k |
real |
0.0 |
Curvature density fraction today |
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omega_lambda |
real |
Dark energy density fraction today |
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hubble |
real |
Hubble parameter H0 (km/s/Mpc) |
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tau |
real |
Optical depth to last-scattering (ignored in background mode) |
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n_s |
real |
Scalar spectral index (ignored in background/thermal mode) |
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A_s |
real |
Scalar spectrum primordial amplitude (ignored in background/thermal mode) |
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k_s |
real |
Power spectrum pivot scale (default 0.05/Mpc) |
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r_t |
real |
0.0 |
Tensor to scalar ratio |
|
n_run |
real |
0.0 |
Running of scalar spectrum d n_s / d log_k |
|
n_t |
real |
0.0 |
Tensor spectral index |
|
omega_nu |
real |
0.0 |
Neutrino density fraction today |
|
massless_nu |
real |
3.046 |
Effective number of massless neutrinos |
|
massive_nu |
int |
0 |
Number of massive neutrinos |
|
sterile_neutrino |
int |
0 |
Number of sterile neutrinos |
|
delta_neff |
real |
0 |
Contribution to N_eff by sterile neutrino |
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sterile_mass_fraction |
real |
Fraction of omega_nu in sterile neutrino |
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yhe |
real |
0.24 |
Helium fraction |
|
w |
real |
-1.0 |
Equation of state of dark energy w(z=0) |
|
wa |
real |
0.0 |
Equation of state parameter in w(z) = w_0 + w_a z / (1+z) |
|
cs2_de |
real |
1.0 |
Dark energy sound speed/c |
Output values¶
Section |
Name |
Type |
Description |
---|---|---|---|
post_friedmann_parameters |
z |
real 1d |
Redshifts of samples |
k_h |
real 1d |
Wavenumber k samples in Mpc/h. |
|
D |
real 2d |
D(k,z) modification to first perturbed Einstein equation |
|
Q |
real 2d |
Q(k,z) modification to second perturbed Einstein equation |
|
cosmological_parameters |
sigma_8 |
real |
Amplitude of linear matter power at 8/h Mpc at z=0. Only calculated if mode=all |
distances |
nz |
int |
Number of z samples |
z |
real 1d |
Redshifts of samples |
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d_a |
real 1d |
Angular diameter distance in Mpc |
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d_m |
real 1d |
Co-moving distance in Mpc |
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d_l |
real 1d |
Luminosity distance in Mpc |
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mu |
real 1d |
Distance modulus |
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h |
real 1d |
Hubble parameter with in units of Mpc |
|
rho |
real 1d |
Matter density, in kg/m^3 Only if mode=all |
|
age |
real |
Age of universe in GYr |
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zdrag |
real |
Redshift where baryons no longer dragged by photons. Only if mode!=background |
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rs_zdrag |
real |
Sound horizon size at zdrag. Only if mode!=background |
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zstar |
real |
Redshift of unity optical depth. Only if mode!=background |
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theta |
real |
Angular size of sound horizon at zstar. Only if mode!=background |
|
chistar |
real |
Comoving distance to zstar. Only if mode!=background |
|
matter_power_lin |
z |
real 1d |
Redshifts of samples. Only if mode=all |
k_h |
real 1d |
K wavenumbers of samples in Mpc/h. Only if mode=all |
|
p_k |
real 2d |
Matter power spectrum at samples in (Mpc/h)^-3. Only if mode=all |
|
linear_cdm_transfer |
z |
real 1d |
Redshifts of samples. Only if mode=all |
k_h |
real 1d |
Wavenumber k of samples in Mpc/h. Only if mode=all |
|
delta_cdm |
real 2d |
Linear CDM transfer function at samples. Only if mode=all |
|
cmb_cl |
ell |
int 1d |
Angular frequencies. Only if mode=cmb or all |
tt |
real 1d |
ell * (ell+1) C_ell^TT / 2 pi in mu K^2. Only if mode=cmb or all |
|
ee |
real 1d |
ell * (ell+1) C_ell^EE / 2 pi in mu K^2. Only if mode=cmb or all |
|
bb |
real 1d |
ell * (ell+1) C_ell^BB / 2 pi in mu K^2. Only if mode=cmb or all |
|
te |
real 1d |
ell * (ell+1) C_ell^TE / 2 pi in mu K^2. Only if mode=cmb or all |
|
PhiPhi |
real 1d |
Lensing spectrum; note ell scaling: ell * (ell+1) C_ell^PhiPhi. Only if mode=cmb or all |