Table of Contents
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Space-Based
G alaxy
S urvey
E xposure
T ime
C alculator
User
M anual
&
C ode
D escription
1.
OVERVIEW......................................................................................................................................................2
2.
COMPILING
T HE
C ODE ...............................................................................................................................3
3.
RUNNING
T HE
C ODE ...................................................................................................................................5
4.
CODE
O UTPUTS:
W L
E TC ........................................................................................................................ 15
5.
CODE
O UTPUTS:
B AO
E TC ...................................................................................................................... 17
6.
CODE
O UTPUTS:
P ZCAL
E TC.................................................................................................................. 18
7.
DETAILED
M ETHODOLOGY
A ND
A SSUMPTIONS............................................................................ 19
D.
L
INE SENSITIVITY AND EFFECTIVE SOLID ANGLE
E
.
XPECTED VS
OBSERVED
............................................................. 24
I.
8.
DATA
S TRUCTURES
A ND
F UNCTIONS ................................................................................................ 33
Version
1 0
Point
o f
C ontact:
Christopher
M .
H irata
Caltech
M /C
3 50-17,
P asadena,
C A
9 1125,
U SA
chirata@tapir.caltech.edu
March
2 8,
2 012
Table
o f
C ontents
.......................................................... 3
....................................................... 10
...................................................... 12
.................................................... 15
..................................................... 19
.......................................................... 19
...................................................... 20
SNR................................................. 22
.................................................. 27
......................................................... 29
.................................................... 29
................................................... 32
......................................................... 33
...................................................... 34
........................................................ 34
.......................................... 35
........................................ 5
.......................................... 7
.................................... 20
....................................... 35
1
..................... 8
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Summary of Contents for Caltech Spice-Based Galaxy Calculator
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Page 1: Table Of Contents
Point o f C ontact: Christopher M . H irata Caltech M /C 3 50-17, P asadena, C A 9 1125, U SA chirata@tapir.caltech.edu March 2 8, 2 012 ... -
Page 2: Overview
(MTF) ...... 35 OUTINES TO COMPUTE THE MODULATION TRANSFER FUNCTION ........35 OUTINES TO COMPUTE GALAXY IMAGE PROPERTIES ........37 OUTINES TO COMPUTE COSMOLOGICAL INFORMATION ....37 OUTINES TO COMPUTE PROPERTIES OF THE GALAXY DISTRIBUTION ... -
Page 3: Compiling The Code
data such as background levels and counts per exposure from objects of various magnitudes s o t hat t he u ser c an d iagnose t his s ituation s hould i t o ccur. Suggestions for improvement, or additional effects that should be included, can be ... - Page 4 Switches the BAO SNR computations from a cut on observed SNR to a cut on expected SNR. In v10 and later, the cut on SNRo is default and this option makes SNRe available. ...
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Page 5: Running The Code
-DNO_OBJ_CONTINUUM Turns off the source continuum contribution to the noise model (usually a minor effect, o f o rder ~ 1% s ince i n w ide-‐bandwidth s litless s pectroscopy t he g alaxy c ontinuum i s almost ... - Page 6 ./baoetc.exe Enter telescope configuration [0=generic, 1=from file]: 0 Enter aperture outer diameter (meters): 1.5 Enter central obscuration (fractional - linear): 0.5 Enter pixel scale (arcsec): 0.37 Enter throughput (total, all orders): 0.6 Enter throughput (1st order): 0.6 The a perture o uter d iameter D s hould b e t hat o f t he l imiting a perture. I n c ases w ith an ...
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Page 7: Telescope Configuration File Format
• The ETC does not currently include the production of multiple charges per photon, which m ay b e s ignificant a t v ery b lue w avelengths. T his s hould n ot b e s ignificant i n the ... -
Page 8: Specifying The Observing Strategy And Detector Characteristics
and t he n umber o f g rid p oints N a t w hich t he t hroughput c urve i s d efined. F ollowing t his i s a ... - Page 9 Enter single exposure time (s): 150 Enter read noise floor (effective e- rms per pixel): 5 Enter dark current (e-/pix/sec): 0.05 Enter ecliptic latitude (degrees): 45 Enter Galactic reddening, E(B-V) (magnitudes): 0.05 Enter number of exposures: 6 The c urrently a vailable d etector t ypes ( and t he i ndex f or i nputting t hem) a re: ...
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Page 10: Wl-Specific Inputs
The position of the observation on the sky is required in order to calculate the zodiacal foreground radiation. This in principle requires the ecliptic latitude β and the difference in ecliptic longitudes of the observation and the Sun, λ−λ... - Page 11 Even if a galaxy is well-‐resolved, it will not be usable for WL if its SNR is too low to recover a shape. For this reason, we include a maximum ellipticity error σ . ...
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Page 12: Bao-Specific Inputs
The galaxy catalog CMC1.dat is used for most analyses is extracted from the CMC (taking r >0 a nd z >0 o bjects). I t i s b ased o n t he ( non-‐randomized) m agnitudes f or a s uite of ... - Page 13 used b ased o n t he o riginal v ersion o f t he C MC. T his o lder m odel i s s till a vailable b y s etting j = ...
- Page 14 Table 1 : T he S chechter f unction p arameters o f t he S obral e t a l ( 2012) H αLF ( model i = 3 ), and ...
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Page 15: Pzcal-Specific Inputs
⎛ ⎞ ⎟ ± 0.2 . H α = −0.62 + 0.25 19 + log ⎜ arcsec ⎝ ⎠ F. PZCAL-specific inputs There a re n o i nputs u nique t o t he P ZCAL m ode. I n g eneral t he i nputs a re i dentical t o €... - Page 16 However, t he E TC d oes n ot p enalize s urveys w ith i nadequate s ampling. I t i s t he u ser’s responsibility ...
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Page 17: Code Outputs: Bao Etc
= 0.2, up to a maximum of z = 3) and total surface density are returned. There are two columns, distinguished by N versus N . ... -
Page 18: Code Outputs: Pzcal Etc
The w avelength λ ( in μ m) a t w hich H α i s o bserved. iii. The E E50 r adius o f t he P SF ( in a rcsec). The ... -
Page 19: Detailed Methodology And Assumptions
Limiting fluxes in W/m2 vs wavelength and galaxy size lambda| 0.0" 0.1" 0.2" |…| 1.0" |…| 0.6000 1.71123E-19 2.15580E-19 2.97796E-19 … 1.08921E-18 0.6500 1.56623E-19 1.97578E-19 2.72938E-19 … 9.95079E-19 0.7000 1.34458E-19 1.69790E-19 2.34528E-19 … 8.52248E-19 0.7500 1.16880E-19 1.47663E-19 2.03902E-19 … 7.38483E-19 0.8000 1.04460E-19 1.32026E-19 1.82229E-19 …... -
Page 20: Galactic Extinction
λ−λ . T he b rightness I a t λ = 0 .5 μ m w as i nterpolated f rom T able 1 7 o f L einert e t a l. ... - Page 21 The effective noise for a galaxy in the absence of source continuum is computed using: Ω σ , Noise where is the effective noise variance per pixel per exposure; Ω...
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Page 22: Snr
where the centroiding integral is . This is used in the routine ˜ Π (u) ∫ 2 π u get_gal_centroid_integral, b ut i s n ot u sed f or a ny c ode o utputs a t p resent. E. - Page 23 . SNRo = t( λ ) t( λ ) + ε t( λ ) λ As long as the maximum is near λ (i.e. for correctly identified lines), we may Taylor-‐ expand ...
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Page 24: Noise Model
where x is the value of SNRe satisfying − Z = 0 (to second order in the SNRe + SNRe noise: ), Θ i s t he H eaviside s tep f unction, a nd δ i s t he D irac i mpulse f unction. ... - Page 25 Here I i s t he s ky b rightness i n u nits o f p ower p er u nit a rea p er u nit s olid a ngle p er u nit λ,sky wavelength; and f (λ) is the all-‐order throughput, i.e. the fraction of the photons entering ...
- Page 26 , ∫ ν ) = f Π( ʹ′ x )d ʹ′ x σ eff,src θ where F is the source continuum flux (in W m Hz ), D ...
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Page 27: Thermal Background Model
G. Thermal background model Thermal emission from the telescope may be a significant noise contribution for WFIRST. I t c an c ome f rom s everal s ources, i ncluding: ... - Page 28 π ) (2 ε − ε )(1 − υ Ω (where υ i s t he l inear c entral o bscuration) f or c ases w ith a p upil m ask, a nd ...
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Page 29: Galaxy Profiles
• Temperatures f or t elescope a nd a ft o ptics: T = T = 2 30 K . • Cold p upil m ask n ot i ncluded, ρ = 1 .05. •... - Page 30 2 π d ϕ . ∫ f (u) = ˜ G (ucos ϕ ,usin ϕ ) 2 π For this reason, we compare to the “noise-‐effective MTF” ; in each of the ˜ G −1/ 2 (u) = [ f (u)] cases ...
- Page 31 The small variations with source color must be considered in data analysis, but will not have a s ignificant e ffect o n t he e xposure t ime c alculation. The ...
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Page 32: Ellipticity Uncertainty
aberrations: defocus, astigmatism, coma, and trefoil; and cases with 25:75, 50:50, and 75:25 mixtures o f d efocus w ith t he o ther t hree a berrations. Figure 2: The rms MTF for an unobstructed aperture with aberrations, relative to the unaberrated case at RMSWFE = 0.2λ. The solid curve is the fitting formula used in the ETC. ... -
Page 33: Data Structures And Functions
Ω ; eff,s Ω the f ormula f or t he e llipticity e rror t hen r eads σ = 2 f /SNR. T he p enalty f actor i s 1 f or a well-‐resolved ... -
Page 34: Interface Functions
#define N_THROUGHPUT_MAX 512 typedef struct { int N; /* Number of points in interpolation grid */ double lambda[N_THROUGHPUT_MAX]; /* Wavelengths (in microns) of nodes */ double throughput[N_THROUGHPUT_MAX]; /* Throughput values */ THROUGHPUT_DATA; The t hroughput c urve i s d efined b y l inear i nterpolation t hrough N p oints s pecified b y t heir wavelength ... -
Page 35: Routines To Set Up Detector Parameters
D. Routines to set up detector parameters void ConfigDetector(int det_type); This routine assigns values to the global variables describing the detectors: PIXSIZE_PHYS, PIX_CD, and (for NIR detectors) T_FRAME and VAR_READ_FRAME. It takes ... - Page 36 double get_gal_Omeff(double reff, PSF_DATA *psf); Returns the effective solid angle Ω of an exponential profile galaxy with effective radius c onvolved w ith p sf. A ll r adii a re i n a rcsec, a nd t he s olid a ngle i s i n a rcsec . ...
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Page 37: Routines To Compute Cosmological Information
Returns t he l imiting A B m agnitude f or s hape m easurements, a s a f unction o f r ( in a rcsec; assumes ... -
Page 38: Routines To Compute Densities Of Observable Galaxies: Wl
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 e ither t he e xpected o r o bserved S NR a s r equested b y t he u ser.) ... -
Page 39: Routines To Compute Noise And Related Quantities
double get_zodi_bkgnd(double ecl_lat, double ecl_dlon, double lambda_min, double lambda_max, THROUGHPUT_DATA *T); The zodiacal light intensity in photons/m /s/arcsec between λ and λ , observed through the throughput curve T. The ecliptic latitude β (ecl_lat) and longitude relative to ... - Page 40 double getThermalBkgndTot(THROUGHPUT_DATA *Thr, double lambda_min, double lambda_max, double filter_throughput, double fratio, double centobs, THERMAL_DATA *thermal, int component); This routine computes the total thermal background in the detector from all three sources (telescope; aft optics upstream of the filter; and the filter and downstream components). The ...
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Page 41: I/Oand Associated Routines
N. I/O and associated routines void error_check_thermal(THERMAL_DATA *thermal); This r outine c hecks a T HERMAL_DATA s tructure f or u nusual o r i llegal v alues. T he p rogram exits ... -
Page 42: Acknowledgements
Included c ode t o c atch i ncompatible c ompilation o ptions. Introduced - DOUT_WL_CAT a nd - DWFE_OVERRIDE o ptions. Added i ndependent S NR c ut f or W L s ource g alaxies. Added ... -
Page 43: Acronyms
11. Acronyms BAO Baryon A coustic O scillations CCD Charge C oupled D evice CDS Correlated D ouble S ample CMC COSMOS ...
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