diff options
| -rw-r--r-- | fg21sim/utils/convert.py | 35 |
1 files changed, 34 insertions, 1 deletions
diff --git a/fg21sim/utils/convert.py b/fg21sim/utils/convert.py index 0fd08b4..85240f8 100644 --- a/fg21sim/utils/convert.py +++ b/fg21sim/utils/convert.py @@ -1,11 +1,14 @@ -# Copyright (c) 2016-2017 Weitian LI <weitian@aaronly.me> +# Copyright (c) 2016-2018 Weitian LI <weitian@aaronly.me> # MIT license """ Utilities for conversion among common astronomical quantities. """ +import numpy as np + from .units import (UnitConversions as AUC, Constants as AC) +from ..share import COSMO def Sb_to_Tb(Sb, freq): @@ -108,3 +111,33 @@ def JyPerPix_to_K(freq, pixelsize): """ factor = Fnu_to_Tb(Fnu=1.0, omega=pixelsize**2, freq=freq) return factor + + +def flux_to_power(flux, z, index=1.0): + """ + Calculate the (spectral) power from the measured flux density at + the same frequency with K-correction taking into account, if the + spectral index is given. + + Parameters + ---------- + flux : float + The measured flux density at a frequency. + Unit: [mJy] + z : float + The redshift to the source. + index : float, optional + The spectral index (α) of the source flux: S(ν) ∝ ν^(-α) + If given, the K-correction is taken into account. + + Returns + ------- + power : float + The calculated (spectral) power at the same frequency as + the flux density measured. + Unit: [W/Hz] + """ + flux *= 1e-29 # [mJy] -> [W/Hz/m^2] + DL = COSMO.DL(z) * AUC.Mpc2m # [m] + power = 4*np.pi * DL**2 * (1+z)**(index-1) * flux # [W/Hz] + return power |