Grid Files

Due to their large size and gradually evolving content (as improvements are made), HDF5 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.

File

Resolution

\(\lambda\) Range

Atmospheric Parameters

sg-OSTAR2002-low.h5 (50MB)

\(\mathcal{R}=1000\)

\([880\,\angstrom, 5.0\,\um]\)

Teff, log(g), Z/Zo

sg-OSTAR2002-medium.h5 (447MB)

\(\mathcal{R}=10000\)

\([880\,\angstrom, 5.0\,\um]\)

Teff, log(g), Z/Zo

sg-OSTAR2002-high.h5 (4.2GB)

\(\mathcal{R}=100000\)

\([880\,\angstrom, 5.0\,\um]\)

Teff, log(g), Z/Zo

The definitions and ranges of the atmospheric 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.

File

Resolution

\(\lambda\) Range

Atmospheric Parameters

sg-BSTAR2006-low.h5 (77MB)

\(\mathcal{R}=1000\)

\([880\,\angstrom, 5\,\um]\)

Teff, log(g), Z/Zo

sg-BSTAR2006-medium.h5 (693MB)

\(\mathcal{R}=10000\)

\([880\,\angstrom, 5\,\um]\)

Teff, log(g), Z/Zo

sg-BSTAR2006-high.h5 (6.5GB)

\(\mathcal{R}=100000\)

\([880\,\angstrom, 5\,\um]\)

Teff, log(g), Z/Zo

The definitions and ranges of the atmospheric parameters are as follows:

  • effective temperature Teff \(= \Teff/\kelvin \in [15000, 30000]\)

  • surface gravity log(g) \(= \log_{10} (g/\cm\,\second^{-2}) \in [1.753.00, 4.75]\)

  • 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.

File

Resolution

\(\lambda\) Range

Atmospheric Parameters

sg-CAP18-large.h5 (73GB)

\(\mathcal{R}=10000\)

\([1300\,\angstrom, 6.5\,\um]\)

Teff, log(g), [Fe/H], [alpha/Fe], log(xi)

sg-CAP18-coarse.h5 (339MB)

\(\mathcal{R}=10000\)

\([1300\,\angstrom, 6.5\,\um]\)

Teff, log(g), [Fe/H]

sg-CAP18-high.h5 (2.9GB)

\(\mathcal{R}=100000\)

\([1300\,\angstrom, 6.5\,\um]\)

Teff, log(g), [Fe/H]

sg-CAP18-ultra.h5 (5.2GB)

\(\mathcal{R}=300000\)

\([1300\,\angstrom, 6.5\,\um]\)

Teff, log(g), [Fe/H]

The definitions and ranges of the atmospheric parameters are as follows:

  • effective temperature Teff \(= \Teff/\kelvin \in [27500, 55000]\)

  • surface gravity log(g) \(= \log_{10} (g/\cm\,\second^{-2}) \in [3.0, 4.5]\)

  • metallicity [Fe/H] \(= \log_{10}[ (\mathrm{Fe}/\mathrm{H}) / (\mathrm{Fe}/\mathrm{H})_{\odot} ] \in [-5.0, 0.5]\)

  • alpha enhancement [alpha/Fe] \(= \log_{10}[ (\alpha/\mathrm{Fe}) / (\alpha/\mathrm{Fe})_{\odot} ] \in [-5.0, 0.5]\)

  • 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.

File

Resolution

\(\lambda\) Range

Atmospheric Parameters

sg-Goettingen-HiRes.h5 (116GB)

variable

\([500\,\angstrom, 5.5\um]\)

Teff, log(g), [Fe/H], [alpha/Fe]

sg-Goettingen-MedRes-A.h5 (6.0GB)

\(\Delta \lambda = 1\,\angstrom\)
(\(10\times\) oversampled)

\([3000\,\angstrom, 1.0\um]\)

Teff, log(g), [Fe/H], [alpha/Fe]

sg-Goettingen-MedRes-R.h5 (18GB)

\(\mathcal{R}=10,000\)
(\(10\times\) oversampled)

\([3000\,\angstrom, 2.5\,\um]\)

Teff, log(g), [Fe/H], [alpha/Fe]

The definitions and ranges of the atmospheric 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] \(= \log_{10}[ (\alpha/\mathrm{Fe}) / (\alpha/\mathrm{Fe})_{\odot} ] \in [-0.2,1.2]\)