Shared Data

GalSim includes some ancillary data along with the installed code. They are installed in the sub-directory share wherever your GalSim module is installed.

The location of these files are given by the variable

galsim.meta_data.share_dir: The installed location of your share directory.

Note

Normally, the installation process will write a file called meta_data.py which sets the above variable automatically to the installation directory on your machine.

However, if you install into a temporary location and then move the entire galsim directory to a different location, this will not have the correct location. (It will instead be set to the temporary location.) If you do this, you should define an environment variable, GALSIM_SHARE_DIR, to the correct location of the share directory. Alternatively, you can set the value of galsim.meta_data.share_dir by hand in any Python programs that might need it.

Usually, you do not need to use the galsim.meta_data.share_dir variable directly. Routines that open files that might be in the share directory will automatically prepend this directory name to the given file name when trying to open the file.

The following files are distributed in the share directory. In each case, we provide the command you would typically use to load the file with the appropriate GalSim class or function.

Shared SED files

vega.txt

Use galsim.SED('vega.txt', wave_type='nm', flux_type='flam')

Specrum of the star Vega (aka Alpha Lyra), derived from HST CALSPEC data. File taken from http://www.stsci.edu/hst/observatory/crds/calspec.html Filename: alpha_lyr_mod_001.fits Clipped on the red side at 2200 nm Units converted to nm and erg/s/cm^2/nm.

CWW_E_ext.sed

Use galsim.SED('CWW_E_ext.sed', wave_type='A', flux_type='flam')

E SED of Coleman, Wu, and Weedman (1980) Extended below 1400 A and beyond 10000 A by Bolzonella, Miralles, and Pello (2000) using evolutionary models of Bruzual and Charlot (1993)

Obtained from ZPHOT code at

http://webast.ast.obs-mip.fr/hyperz/zphot_src_1.1.tar.gz

Truncated to wavelengths less than 22050 Angstroms, and thinned by galsim.utilities.thin_tabulated_values to a relative error of 1.e-5 with fast_search=False. See devel/modules/getSEDs.py for details.

CWW_E_ext_more.sed

Use galsim.SED('CWW_E_ext_more.sed', wave_type='A', flux_type='flam')

Same as CWW_E_ext.sed, but thinned to a relative error of 1.e-3

CWW_Im_ext.sed

Use galsim.SED('CWW_Im_ext.sed', wave_type='A', flux_type='flam')

Im SED of Coleman, Wu, and Weedman (1980) Extended below 1400 A and beyond 10000 A by Bolzonella, Miralles, and Pello (2000) using evolutionary models of Bruzual and Charlot (1993)

Obtained from ZPHOT code at ‘http://webast.ast.obs-mip.fr/hyperz/zphot_src_1.1.tar.gz’

Truncated to wavelengths less than 22050 Angstroms, and thinned by galsim.utilities.thin_tabulated_values to a relative error of 1.e-5 with fast_search=False. See devel/modules/getSEDs.py for details.

CWW_Im_ext_more.sed

Use galsim.SED('CWW_Im_ext_more.sed', wave_type='A', flux_type='flam')

Same as CWW_Im_ext.sed, but thinned to a relative error of 1.e-3

CWW_Sbc_ext.sed

Use galsim.SED('CWW_Sbc_ext.sed', wave_type='A', flux_type='flam')

Sbc SED of Coleman, Wu, and Weedman (1980) Extended below 1400 A and beyond 10000 A by Bolzonella, Miralles, and Pello (2000) using evolutionary models of Bruzual and Charlot (1993)

Obtained from ZPHOT code at ‘http://webast.ast.obs-mip.fr/hyperz/zphot_src_1.1.tar.gz’

Truncated to wavelengths less than 22050 Angstroms, and thinned by galsim.utilities.thin_tabulated_values to a relative error of 1.e-5 with fast_search=False. See devel/modules/getSEDs.py for details.

CWW_Sbc_ext_more.sed

Use galsim.SED('CWW_Sbc_ext_more.sed', wave_type='A', flux_type='flam')

Same as CWW_Sbc_ext.sed, but thinned to a relative error of 1.e-3

For more details about how the above files were generated, see the script:

GalSim/devel/getSEDs.py