Grid Files
Due to their large size and gradually evolving content (as
improvements are made), specgrid files are
not shipped as part of the rhdtownsend/msg git repository; they
must be downloaded separately (the sole exception is the demo grid,
$MSG_DIR/data/grids/sg-demo.h5
). This chapter describes the
various grids currently available.
OSTAR2002 Grids
The OSTAR2002 grids are based on the line-blanketed O-star model atmospheres published in Lanz & Hubeny (2003). Spectra are calculated from these atmospheres using SYNSPEC, and their angle dependence parameterized with the CLARET limb-darkening law.
Specgrid File |
Resolution |
\(\lambda\) Range |
Photospheric Parameters |
---|---|---|---|
sg-OSTAR2002-low.h5 (50MB) |
\(\mathcal{R}=1000\) |
\([880\,\angstrom, 5.0\,\um]\) |
|
sg-OSTAR2002-medium.h5 (447MB) |
\(\mathcal{R}=10000\) |
\([880\,\angstrom, 5.0\,\um]\) |
|
sg-OSTAR2002-high.h5 (4.2GB) |
\(\mathcal{R}=100000\) |
\([880\,\angstrom, 5.0\,\um]\) |
|
The definitions and ranges of the photospheric parameters are as follows:
effective temperature
Teff
\(= \Teff/\kelvin \in [27500, 55000]\)surface gravity
log(g)
\(= \log_{10} (g/\cm\,\second^{-2}) \in [3.0, 4.75]\)metallicity
Z/Zo
\(= Z/Z_{\odot} \in [0.02, 2]\)
BSTAR2006 Grids
The BSTAR2006 grids are based on the line-blanketed B-star model atmospheres published in Lanz & Hubeny (2007). Spectra are calculated from these atmospheres using SYNSPEC, and their angle dependence parameterized with the CLARET limb-darkening law.
Specgrid File |
Resolution |
\(\lambda\) Range |
Photospheric Parameters |
---|---|---|---|
sg-BSTAR2006-low.h5 (77MB) |
\(\mathcal{R}=1000\) |
\([880\,\angstrom, 5\,\um]\) |
|
sg-BSTAR2006-medium.h5 (693MB) |
\(\mathcal{R}=10000\) |
\([880\,\angstrom, 5\,\um]\) |
|
sg-BSTAR2006-high.h5 (6.5GB) |
\(\mathcal{R}=100000\) |
\([880\,\angstrom, 5\,\um]\) |
|
The definitions and ranges of the photospheric parameters are as follows:
effective temperature
Teff
\(= \Teff/\kelvin \in [15000, 30000]\)surface gravity
log(g)
\(= \log_{10} (g/\cm\,\second^{-2}) \in [1.75, 4.75]\)metallicity
Z/Zo
\(= Z/Z_{\odot} \in [0, 2]\)
CAP18 Grids
The CAP18 grids are based on the data published in Allende Prieto et al. (2018) (the letters ‘CAP’ are the initials of the first author). The angle dependence of spectra is parameterized with the CONST limb-darkening law.
Specgrid File |
Resolution |
\(\lambda\) Range |
Photospheric Parameters |
---|---|---|---|
sg-CAP18-large.h5 (73GB) |
\(\mathcal{R}=10000\) |
\([1300\,\angstrom, 6.5\,\um]\) |
|
sg-CAP18-coarse.h5 (339MB) |
\(\mathcal{R}=10000\) |
\([1300\,\angstrom, 6.5\,\um]\) |
|
sg-CAP18-high.h5 (2.9GB) |
\(\mathcal{R}=100000\) |
\([1300\,\angstrom, 6.5\,\um]\) |
|
sg-CAP18-ultra.h5 (5.2GB) |
\(\mathcal{R}=300000\) |
\([1300\,\angstrom, 6.5\,\um]\) |
|
The definitions and ranges of the photospheric parameters are as follows:
effective temperature
Teff
\(= \Teff/\kelvin \in [3500, 30000]\)surface gravity
log(g)
\(= \log_{10} (g/\cm\,\second^{-2}) \in [0.0, 5.0]\)metallicity
[Fe/H]
\(= \log_{10}[ (\mathrm{Fe}/\mathrm{H}) / (\mathrm{Fe}/\mathrm{H})_{\odot} ] \in [-5.0, 0.5]\)alpha enhancement
[alpha/Fe]
\(= \log_{10}[ (\alpha/\mathrm{Fe}) / (\alpha/\mathrm{Fe})_{\odot} ] \in [-1.0, 1.0]\)microturbulent velocity
log(xi)
\(= \log_{10} (\xi/\cm\,\second^{-1}) \in [-0.301,0.903]\)
Göttingen Grids
The Göettingen grids are based on the data described in Husser et al. (2013) and available for download from phoenix.astro.physik.uni-goettingen.de. The angle dependence of spectra is parameterized with the CONST limb-darkening law.
Specgrid File |
Resolution |
\(\lambda\) Range |
Photospheric Parameters |
---|---|---|---|
sg-Goettingen-HiRes.h5 (116GB) |
variable |
\([500\,\angstrom, 5.5\um]\) |
|
sg-Goettingen-MedRes-A.h5 (6.0GB) |
\(\Delta \lambda = 1\,\angstrom\) |
\([3000\,\angstrom, 1.0\um]\) |
|
sg-Goettingen-MedRes-R.h5 (18GB) |
\(\mathcal{R}=10,000\) |
\([3000\,\angstrom, 2.5\,\um]\) |
|
The definitions and ranges of the photospheric parameters are as follows:
effective temperature
Teff
\(= \Teff/\kelvin \in [2\,300, 12\,000]\)surface gravity
log(g)
\(= \log_{10}(g/\cm\,\second^{-2}) \in [0.0, 6.0]\)metallicity
[Fe/H]
\(= \log_{10}[ (\mathrm{Fe}/\mathrm{H}) / (\mathrm{Fe}/\mathrm{H})_{\odot} ] \in [-4.0, 1.0]\)alpha enhancement
[alpha/H]
\(= \log_{10}[ (\alpha/\mathrm{Fe}) / (\alpha/\mathrm{Fe})_{\odot} ] \in [-0.2,1.2]\)