COS Spectral Simulator

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History of Changes (Last Updated April 13, 2008)

All sensitivities have been updated to measured values of the
fully assembled flight hardware (November 16, 2005).

The BOA transmission has been reduced from 1% (predicted) to
0.4% measured (October 27, 2006).

The FUV and NUV pixel sizes (in Å) have been slightly modifed to match
2006 calibration results.

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The BOA transmission has been adjusted to a wavelength dependent form
(0.4% at 3000Å linearly increasing to 0.8% at 1100Å, April 17, 2007).

The FUV and NUV pixel sizes (in Å) have been slightly modifed to match
2006 calibration results. The pixel sizes being used are currently averages
over all modes for a given grating. An upgrade to use the actual pixel sizes
for each grating setting, segment, stripe, etc in planned over the next few weeks.

Modified the NUV and FUV wavebands to match the expected on-orbit values.
These values were obtained during ground calibration testing, whereas
previous wavebands were based upon ray-trace model predictions (Nov. 12, 2007).

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Select The Desired COS Grating:

FUV : Detector : FUV01 FUV02 (Flight Detector)

G130M : Central Wavelength = Å
G160M : Central Wavelength = Å
G140L : Central Wavelength = Å

NUV :
G185M : Central Wavelength = Å
G225M : Central Wavelength = Å
G285M : Central Wavelength = Å
G230L : Central Wavelength = Å

Select the desired COS aperture : PSA BOA*
* see notes about decreased resolution when using the BOA

Select the desired COS observing mode : Time-Tag ACCUM

Observe with TAGFLASH mode ?
No (Only option for ACCUM)
Yes (Default for Time-Tag)

FP-SPLIT* ? No 2 4 8 16 20
*Currently, the only effect of the FP-SPLIT setting is in orbit calculation.
Continuum noise and wavelength coverage are NOT affected.
Only FUV G130M and G160M can use FP-SPLIT greater than 8.

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Target :
QSO at z =
Power Law with F_λ = F₀ (λ/ Å )
Black Body with T= K
Step up down at Z= by a factor of
Uniform single line emission with radius of " at Å, and an intensity of
Rayleighs, or ergs/s/cm²/arcsec²
Kurucz Model Spectra :

Other :

User Supplied Spectrum :
I have anonymous ftp'd my two column [wave,flux] ASCII file
to arlsrv.colorado.edu as /incoming/
Pt-Ne Wavelength Calibration Lamp (typically 60 second in duration)
Pt-Cr-Ne Wavelength Test Lamp (FUV ONLY, typically 60 second in duration)
Flat Field Lamp (typically 10 seconds in duration)

Target Flux/Normalization (ignored for uniform emission, Flat Field and Platinum Lamps):

ergs/s/cm²/Å at Å (i.e, 1E-15 ergs/s/cm²/Å @ 1250Å)
Magnitude (m)=, with the target scaling as F_λ~F₀(m) (λ/ Å ) ^*
GALEX NUV Magnitude (m) =, with the target scaling as F_λ~F₀(m) (λ/ Å ) ^*
GALEX FUV Magnitude (m) =, with the target scaling as F_λ~F₀(m) (λ/ Å ) ^*
* a spectral index of -1 is a good guess for galaxies, use 0 to just scale by F₀
No Normalization

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Exposure Time : seconds

Redden spectrum ? : No
Yes, after before normalization, with E(B-V)=

Number of simulated absorption features :

Add Simulated Galactic absorption features ? Yes No

Estimate Number of Orbits ? Yes No
If Yes, then specify the absolute value of the Declination of the target :
00 - 18° 18 - 33° 33 - 43°
43 - 48° 48 - 53° 53 - 58°
58 - 63° 63 - 68° 68 - 73°
73 - 88° 88 - 90°
CVZ (Target is in the continous viewing zone)
Moving (Solar System target near ecliptic)
Shadow (25 minute orbit restricted to the Earth's shadow)

Add Geocoronal Emission ? No Daytime Nightime

Add Simulated Detector Noise ? Yes No

Add Photon Noise ? Yes No

Perform Background Subtraction ? Yes No

Color Scheme: White on Black Black on White

Output Format: PNG JPEG TEXT EPS PS

For more information on COS, visit the STSCI site here .
Comments, Questions and Feature Requests can be sent to : spenton@casa.colorado.edu