Caltech Spice-Based Galaxy Calculator Survey - page 38
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get_n_Detectable includes a correction for the conversion from SNRe to SNRo. (That
is, get_P_Detectable always cuts on the expected SNR, but get_n_Detectable cuts
on either the expected or observed SNR as requested by the user.)
double get_n_galaxies(double z, PSF_DATA *psf, double var_1exp, double
calib_1exp, int N_exp, double significance_cut, int model, double
*stats);
This routine returns the commoving density of detectable galaxies at redshift z and flux F
Hα
would be detectable at significance_cut σ. The routine requires ancillary data: the
PSF, noise variance per exposure (in electrons
2
arcsec
−2
), and the calibration (electrons per
exposure per W m
−2
), and number of exposures. Ancillary information is returned in
*stats if this input is not NULL: stats[0] is assigned the geometric mean of F
Hα
(in W
m
−2
); stats[1] is assigned the standard deviation of ln F
Hα
; stats[2] is assigned the
skewness of ln F
Hα
; and stats[3] is assigned the kurtosis of ln F
Hα
.
K. Routines to compute densities of observable galaxies: WL
double get_dNdA_WL_gal2(double reffmin, double reffmax, double zmin,
double zmax, char GalaxyCat[], double lambda_min, double lambda_max,
PSF_DATA *psf, int N_exp, double var_1exp, double calib_1exp, double
max_ellip_err, double *dNeffdA, char OutFile[], char outmode);
double get_dNdA_WL_gal(double reffmin, double reffmax, double zmin,
double zmax, char GalaxyCat[], double lambda_min, double lambda_max,
PSF_DATA *psf, int N_exp, double var_1exp, double calib_1exp, double
max_ellip_err, double *dNeffdA);
Either of these two functions will return the number density of galaxies (per deg
2
) with
measurable shapes in the range z
min
< z < z
max
and r
eff,min
< r
eff
< r
eff,max
. The galaxies are
taken from the file name GalaxyCat. The routine requires ancillary data: the PSF, noise
variance per exposure (in electrons
2
arcsec
−2
), and the calibration (electrons per exposure
for a 0 magnitude AB source), and number of exposures. If dNeffdA is not null, the
effective number density of galaxies (per deg
2
) is returned to *dNeffdA.
The difference between these two functions is that get_dNdA_WL_gal2 outputs a
table of resolved galaxies to OutFile[] (unless it receives the null pointer, in which case
the behavior is identical to get_dNdA_WL_gal – indeed, the latter calls
get_dNdA_WL_gal2 with the null pointer). The output file is a 4-‐column list of galaxies:
each row contains the galaxy ID; the redshift; the effective radius in arcsec; and the
ellipticity uncertainty σ
e
. The output file is either written (‘w’) or appended (‘a’) depending
on outmode.
L. Routines to compute the foreground radiation and absorption
double Galactic_Alambda__EBV(double lambda);
The Galactic reddening law, A
λ
/E(B−V), given λ in μm.