GALEX Grism Calibration

Four stars around 4 hours RA (November 2008):
HZ 2    0412+11  14.02   (lots of grism data, but few field stars)
GD 50   0348-00  14.05   (good field, 2.1 times brighter than HZ 2)
HZ 4    0355+09  14.45   (good field, 2.9 times fainter than HZ 2)
LB 227  0409+17  15.24   (7.7 times fainter than HZ 2)


Comparison between 2004 and 2007 calibrations: NUV 1st order ... FUV 2nd order ...

Comparison between Old ETC(<=2007) and New 2007 calibrations: NUV 1st order ... FUV 2nd order


Ground Calibration
ASCII tables of effective area:
EA_ground-nuv_1.tbl ... EA_ground-nuv_2.tbl ... EA_ground-fuv_2.tbl ... EA_ground-fuv_3.tbl
Space Calibration (as of 02 April 2004) (based on BD+33)
ASCII tables of effective area:
EA_02apr04-nuv_1.tbl ... EA_02apr04-nuv_2.tbl ... EA_02apr04-fuv_2.tbl ... EA_02apr04-fuv_3.tbl

Plots of ground vs. space calibration:
EA_nuv1-gvs.ps ... EA_nuv2-gvs.ps ... EA_fuv2-gvs.ps ... EA_fuv3-gvs.ps

Here are the current (June 2004) wavelength cutoffs used for the final reduced spectra: extraction_ranges_jun04.txt .

Plots of relative variations of response among 42 spectra of BD+33 taken at different grism angles and different detector positions:
NUV 1st order (PS) ... NUV 2nd order (PS) ... FUV 2nd order (PS) ... FUV 3rd order (PS)

Tar file of ASCII tables of flux calibration (based on BD+33). Files contain four columns of wavelength, extracted flux (pho/sec/cm^2/sec), HST calibration spectrum, and smoothed HST calibration standard. Files with the same first 5 letters were taken during the same visit with the star at different positions on the detector.


GALEX Standard Stars for Grism Calibration

GIF image (10 x 10 arcmin): BD+33d2642 HZ 44 ... ...
GRSPA table (5=best,1=worst): BD+33d2642 HZ 44 ... ...
Plot of GRSPA angles: BD+33d2642 HZ 44 ... ...
Spectral data (Flam v. Ang): BD+33d2642 HZ 44 LDS 749B G 93-48
Simulated GALEX Spectra Plots: BD+33d2642 HZ 44 ... ...
List of observations: BD+33d2642 HZ 44 LDS 749B G 93-48
Coordinate Name (2000): 1551+3256 1323+3608 2132+0015 2152+0223
RA,Dec (2000): 237.99942, +32.94856 200.897375, +36.133333 323.06563, +00.25378 328.10554, +02.39008

Simulated LDS 749b plots (with 0.65 pessimism factor):
NUV pho/sec ... FUV pho/sec ... Flux Calibrated ... S/N per second per 5 Angstrom bin .
Simulated GALEX Spectral Plots with noise (red line is calibration spectrum):
BD+33: (100 seconds) (500 seconds) (1500 seconds)
HZ 44: (100 seconds) (500 seconds) (1500 seconds)

Simulated GALEX Spectral ASCII Tables:
BD+33: (FUV) (NUV) (Flux 1500s)
HZ 44: (FUV) (NUV) (Flux 1500s)

CALSPEC (link to .stsci.edu)
CALSPEC (copy of web page with table of stars)
HST Standards (list of stars)
Spectral Plots of HST Standards (PS)
Standard Star List (.rl.ac.uk)
GRSPA Diagram (GIF)
Grism Offset vs. Wavelength (PS)
Grism Dispersion (Angstroms per Arcsecond) (PS)
Grism Resolution in Angstroms (5" PSF) (PS)
Grism Resolution in km/s (5" PSF) (PS)

First grism spectra.
Compare BD+33 Estimate with actual spectrum from Eclipse 455 on (pho/sec/arcsec vs. offset arcsecond)
Division of Actual by Estimate on arcsecond scale
Real vs. Actual on (Flux vs. Angstrom)