frb.dlas - Intervening Galaxies (DLAs)

Assessing impact of intervening galaxies (DLAs) on FRB measurements, based on Prochaska & Neeleman 2017.

Module for assessing impact of intervening galaxies (DLAs) on FRB measurements Based on calclations presented in Prochaska & Neeleman 2017

frb.dlas.approx_avgDM(zeval, dla_model='atan', verbose=False)[source]

Calculate the average DM from intervening galaxies This method is approximate (and fast) and accurate to better than 1% in-so-far as the analysis is correct.

From Prochaska & Neeleman 2017

Parameters:

  • zeval (float or ndarray) – Redshift(s) for evaluation

  • dla_model (str, optional)

Returns:

avgDM – Units of pc/cm**3

Return type:

Quantity (depending on type of input z)

frb.dlas.monte_DM(zeval, model='atan', nrand=100, verbose=False)[source]
Parameters:

  • zeval (float or ndarray) – Array of redshifts for evaluation

  • model

  • nrand (int, optional) – Number of samples on NHI

  • verbose (bool, optional)

Returns:

rand_DM – Random DM values Reported in pc/cm**3 (unitless array)

Return type:

ndarray

frb.dlas.monte_tau(zeval, nrand=100, nHI=0.1, avg_ne=-2.6, sigma_ne=0.5, cosmo=None, lobs=<Quantity 50. cm>, turb=None)[source]

Generate random draws of tau at a series of redshifts

Parameters:

  • zeval (ndarray) – Array of redshifts for evaluation

  • nrand (int, optional) – Number of samples on NHI

  • avg_ne (float, optional) – Average log10 electron density / cm**3

  • sigma_ne (float, optional) – Error in log10 ne

  • nHI (float, optional) – Fiducial value for n_HI; used for DL value

  • lobs (Quantity) – Wavelength for analysis

  • turb (Turbulence object, optional) – Usually defined internally and that is the highly recommended approach

  • cosmo (astropy.cosmology, optional) – Defaults to defs.frb_cosmo

Returns:

rand_tau – Random tau values reported in ms (but without explicit astropy Units)

Return type:

ndarray (nrand, nz)