calc_zmax

zdm.vvmax.calc_zmax(s0, z0, DM0, DMcosmic0, w0, freq, tsamp, Macquartz, MacquartDM, alpha)

Routine which calculates the maximum redshift at which an FRB could have been detected.

We begin with the ratio s0, which is SNR(det)/SNR(thresh) This tells us how much fluence we can lose as a function of redshift

We then account for luminosity distance, and changing efficiency with distance

‘0’ properties indicate those at detection

Macquartz and MacquartDM are pre-computed values of Macquart relation

We must have values of z which span the range from the minimum z at which the FRB lies, to the maximum z at which it could be detected E.g. at S/N of 1000, that’s a factor of ~10 for SNRthresh=10

INPUTS:

s0 [float]: measured SNR/SNRthresh of detected FRB z0 [float]: measured FRB redshift DM0 [float]: measured FRB total dispersion measures [pc cm^-3] DMcosmic0: estimated FRB cosmic dispersion measures [pc cm^-3] w0 [float]: measured FRB width [ms] freq [float]: frequency of detection [MHz] tsamp [float]: integration time of data [ms] Macquartz [float]: redshift estimated from the Macquart relation MacquartDM [float]: cosmic dispersion measure estimated from the Macquart relation alpha [float]: frequency dependence of FRBs - Fnu ~ nu^lpha

Returns:

maximum redshift that the FRB could have been detected at