Mission Overview

Pure-Hydrogen White Dwarf Models ("WD-GRID")

 

Primary Investigator: Ralph Bohlin

HLSP Authors: Ralph Bohlin

Released: 2020-06-02

Updated: 2020-06-02

Primary Reference(s): Bohlin et al. 2020

DOI: 10.17909/t9-7myn-4y46

Citations: See ADS Statistics

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Change in the SED for each of the three primary flux standards and the average change due to changes in the reference models. The average exceeds 1% only longward of 10 microns and shortward of 1670 Angstroms. Because the absorption lines are masked in the flux calibration process, the illustrated sharp spikes at line centers have no effect on the results, i.e., the measured STIS flux distibutions.  From Bohlin et al. 2020.

Overview

NLTE calculations of hot white dwarf (WD) model atmospheres are the cornerstone of modern flux calibrations for the Hubble Space Telescope (HST) and for the CALSPEC database. These theoretical spectral energy distributions (SEDs) provide the relative flux vs. wavelength, and only the absolute flux level remains to be set by reconciling the measured absolute flux of Vega in the visible with the Midcourse Space Experiment (MSX) values for Sirius in the mid-IR. The most recent SEDs calculated by the tlusty and tmap NLTE model atmosphere codes for the primary WDs G191B2B, GD153, and GD71 show improved agreement to 1% from 1500 Angstroms to 30 microns, in comparison to the previous 1% consistency only from 2000 Angstroms to 5 microns. These new NLTE models of hot WDs now provide consistent flux standards from the FUV to the mid-IR.

Model grids from both the TLUSTY207 and TMAP2019 NLTE software codes are presented across a range of stellar parameters.  Both grids contain 132 models with effective temperature (T_eff) in the range 20,000 - 95,000 K and gravity (logg) between 7.0 and 9.5, with six steps of 0.5. The steps in T_eff are 2,000 K between 20,000 and 40,000 K and 5,000 K between 40,000 and 95,000 K.  The wavelengths are presented in Angstroms, measured in vaccuum.  The fluxes are Eddington fluxes, with different conversions for the two model sets to needed to convert to physical fluxes.  See the Bohlin et al. 2020 paper for important information on how to use and convert the fluxes from these models.

Data Products

The data files are sorted into directories based on the set, "tlusty207" or "tmap2019".  Both txt and FITS versions are available.

Data file naming convention for the tlusty207 set:

hlsp_wd-grid_tlusty207_nlte-model_<teffgrav>_r5000_v1_<exten>

where:

  • <teffgrav> is a string representation of the effective temperature and surface gravity of the model, in the form of "t???g???n".  The first part is the effective temperature divided by 100, the second part is the surface gravity multiplied by 100, and the 'n' specifies that these models are non-LTE.  As a specific example, the string "t950g750n" corresponds to an effective temperature of 95,000 K and a surface gravity of log(g) = 7.50.
  • <exten> can be "cont.fits", "cont.txt", "spec.fits", or "spec.txt".  The "cont" files correspond to the theoretical continuum fluxes, while the "spec" files contain the spectrum that includes all the metal lines in it.

Data file naming convention for the tmap2019 set:

hlsp_wd-grid_tmap2019_nlte-model_<teffgrav>_r50000_v1_spec.<exten>

where:

  • <teffgrav> is a string representation of the effective temperature and surface gravity of the model, in the form of "teff-logg", where <teff> is the 7-digit, zero-padded effective temperature, and <logg> is the surface gravity.  As a specific example, the string "0040000-9.50" corresponds to an effective temperature of 40,000 K and a surface gravity of log(g) = 9.50.
  • <exten> = either "fits" or "txt", depending on what data type it is.

Data file types:

_cont.fits, _cont.txt The theoretical continuum fluxes for the model (tlusty207 model set only).
_spec.fits,  _spec.txt The model spectrum including metal lines (both tlusty207 and tmap2019 model sets, but note that the available columns are different between the two).

Data Access

For important information on these models, including how to convert the fluxes to physical fluxes, consult Bohlin et al. 2020 and see the README file for the TLUSTY207 and the README file for the TMAP2019 sets.

T_eff log(g) TLUSTY207 CONT TLUSTY207 SPEC TMAP2019
20000 7.00 FITS | TXT FITS | TXT FITS | TXT
20000 7.50 FITS | TXT FITS | TXT FITS | TXT
20000 8.00 FITS | TXT FITS | TXT FITS | TXT
20000 8.50 FITS | TXT FITS | TXT FITS | TXT
20000 9.00 FITS | TXT FITS | TXT FITS | TXT
20000 9.50 FITS | TXT FITS | TXT FITS | TXT
22000 7.00 FITS | TXT FITS | TXT FITS | TXT
22000 7.50 FITS | TXT FITS | TXT FITS | TXT
22000 8.00 FITS | TXT FITS | TXT FITS | TXT
22000 8.50 FITS | TXT FITS | TXT FITS | TXT
22000 9.00 FITS | TXT FITS | TXT FITS | TXT
22000 9.50 FITS | TXT FITS | TXT FITS | TXT
24000 7.00 FITS | TXT FITS | TXT FITS | TXT
24000 7.50 FITS | TXT FITS | TXT FITS | TXT
24000 8.00 FITS | TXT FITS | TXT FITS | TXT
24000 8.50 FITS | TXT FITS | TXT FITS | TXT
24000 9.00 FITS | TXT FITS | TXT FITS | TXT
24000 9.50 FITS | TXT FITS | TXT FITS | TXT
26000 7.00 FITS | TXT FITS | TXT FITS | TXT
26000 7.50 FITS | TXT FITS | TXT FITS | TXT
26000 8.00 FITS | TXT FITS | TXT FITS | TXT
26000 8.50 FITS | TXT FITS | TXT FITS | TXT
26000 9.00 FITS | TXT FITS | TXT FITS | TXT
26000 9.50 FITS | TXT FITS | TXT FITS | TXT
28000 7.00 FITS | TXT FITS | TXT FITS | TXT
28000 7.50 FITS | TXT FITS | TXT FITS | TXT
28000 8.00 FITS | TXT FITS | TXT FITS | TXT
28000 8.50 FITS | TXT FITS | TXT FITS | TXT
28000 9.00 FITS | TXT FITS | TXT FITS | TXT
28000 9.50 FITS | TXT FITS | TXT FITS | TXT
30000 7.00 FITS | TXT FITS | TXT FITS | TXT
30000 7.50 FITS | TXT FITS | TXT FITS | TXT
30000 8.00 FITS | TXT FITS | TXT FITS | TXT
30000 8.50 FITS | TXT FITS | TXT FITS | TXT
30000 9.00 FITS | TXT FITS | TXT FITS | TXT
30000 9.50 FITS | TXT FITS | TXT FITS | TXT
32000 7.00 FITS | TXT FITS | TXT FITS | TXT
32000 7.50 FITS | TXT FITS | TXT FITS | TXT
32000 8.00 FITS | TXT FITS | TXT FITS | TXT
32000 8.50 FITS | TXT FITS | TXT FITS | TXT
32000 9.00 FITS | TXT FITS | TXT FITS | TXT
32000 9.50 FITS | TXT FITS | TXT FITS | TXT
34000 7.00 FITS | TXT FITS | TXT FITS | TXT
34000 7.50 FITS | TXT FITS | TXT FITS | TXT
34000 8.00 FITS | TXT FITS | TXT FITS | TXT
34000 8.50 FITS | TXT FITS | TXT FITS | TXT
34000 9.00 FITS | TXT FITS | TXT FITS | TXT
34000 9.50 FITS | TXT FITS | TXT FITS | TXT
36000 7.00 FITS | TXT FITS | TXT FITS | TXT
36000 7.50 FITS | TXT FITS | TXT FITS | TXT
36000 8.00 FITS | TXT FITS | TXT FITS | TXT
36000 8.50 FITS | TXT FITS | TXT FITS | TXT
36000 9.00 FITS | TXT FITS | TXT FITS | TXT
36000 9.50 FITS | TXT FITS | TXT FITS | TXT
38000 7.00 FITS | TXT FITS | TXT FITS | TXT
38000 7.50 FITS | TXT FITS | TXT FITS | TXT
38000 8.00 FITS | TXT FITS | TXT FITS | TXT
38000 8.50 FITS | TXT FITS | TXT FITS | TXT
38000 9.00 FITS | TXT FITS | TXT FITS | TXT
38000 9.50 FITS | TXT FITS | TXT FITS | TXT
40000 7.00 FITS | TXT FITS | TXT FITS | TXT
40000 7.50 FITS | TXT FITS | TXT FITS | TXT
40000 8.00 FITS | TXT FITS | TXT FITS | TXT
40000 8.50 FITS | TXT FITS | TXT FITS | TXT
40000 9.00 FITS | TXT FITS | TXT FITS | TXT
40000 9.50 FITS | TXT FITS | TXT FITS | TXT
45000 7.00 FITS | TXT FITS | TXT FITS | TXT
45000 7.50 FITS | TXT FITS | TXT FITS | TXT
45000 8.00 FITS | TXT FITS | TXT FITS | TXT
45000 8.50 FITS | TXT FITS | TXT FITS | TXT
45000 9.00 FITS | TXT FITS | TXT FITS | TXT
45000 9.50 FITS | TXT FITS | TXT FITS | TXT
50000 7.00 FITS | TXT FITS | TXT FITS | TXT
50000 7.50 FITS | TXT FITS | TXT FITS | TXT
50000 8.00 FITS | TXT FITS | TXT FITS | TXT
50000 8.50 FITS | TXT FITS | TXT FITS | TXT
50000 9.00 FITS | TXT FITS | TXT FITS | TXT
50000 9.50 FITS | TXT FITS | TXT FITS | TXT
55000 7.00 FITS | TXT FITS | TXT FITS | TXT
55000 7.50 FITS | TXT FITS | TXT FITS | TXT
55000 8.00 FITS | TXT FITS | TXT FITS | TXT
55000 8.50 FITS | TXT FITS | TXT FITS | TXT
55000 9.00 FITS | TXT FITS | TXT FITS | TXT
55000 9.50 FITS | TXT FITS | TXT FITS | TXT
60000 7.00 FITS | TXT FITS | TXT FITS | TXT
60000 7.50 FITS | TXT FITS | TXT FITS | TXT
60000 8.00 FITS | TXT FITS | TXT FITS | TXT
60000 8.50 FITS | TXT FITS | TXT FITS | TXT
60000 9.00 FITS | TXT FITS | TXT FITS | TXT
60000 9.50 FITS | TXT FITS | TXT FITS | TXT
65000 7.00 FITS | TXT FITS | TXT FITS | TXT
65000 7.50 FITS | TXT FITS | TXT FITS | TXT
65000 8.00 FITS | TXT FITS | TXT FITS | TXT
65000 8.50 FITS | TXT FITS | TXT FITS | TXT
65000 9.00 FITS | TXT FITS | TXT FITS | TXT
65000 9.50 FITS | TXT FITS | TXT FITS | TXT
70000 7.00 FITS | TXT FITS | TXT FITS | TXT
70000 7.50 FITS | TXT FITS | TXT FITS | TXT
70000 8.00 FITS | TXT FITS | TXT FITS | TXT
70000 8.50 FITS | TXT FITS | TXT FITS | TXT
70000 9.00 FITS | TXT FITS | TXT FITS | TXT
70000 9.50 FITS | TXT FITS | TXT FITS | TXT
75000 7.00 FITS | TXT FITS | TXT FITS | TXT
75000 7.50 FITS | TXT FITS | TXT FITS | TXT
75000 8.00 FITS | TXT FITS | TXT FITS | TXT
75000 8.50 FITS | TXT FITS | TXT FITS | TXT
75000 9.00 FITS | TXT FITS | TXT FITS | TXT
75000 9.50 FITS | TXT FITS | TXT FITS | TXT
80000 7.00 FITS | TXT FITS | TXT FITS | TXT
80000 7.50 FITS | TXT FITS | TXT FITS | TXT
80000 8.00 FITS | TXT FITS | TXT FITS | TXT
80000 8.50 FITS | TXT FITS | TXT FITS | TXT
80000 9.00 FITS | TXT FITS | TXT FITS | TXT
80000 9.50 FITS | TXT FITS | TXT FITS | TXT
85000 7.00 FITS | TXT FITS | TXT FITS | TXT
85000 7.50 FITS | TXT FITS | TXT FITS | TXT
85000 8.00 FITS | TXT FITS | TXT FITS | TXT
85000 8.50 FITS | TXT FITS | TXT FITS | TXT
85000 9.00 FITS | TXT FITS | TXT FITS | TXT
85000 9.50 FITS | TXT FITS | TXT FITS | TXT
90000 7.00 FITS | TXT FITS | TXT FITS | TXT
90000 7.50 FITS | TXT FITS | TXT FITS | TXT
90000 8.00 FITS | TXT FITS | TXT FITS | TXT
90000 8.50 FITS | TXT FITS | TXT FITS | TXT
90000 9.00 FITS | TXT FITS | TXT FITS | TXT
90000 9.50 FITS | TXT FITS | TXT FITS | TXT
95000 7.00 FITS | TXT FITS | TXT FITS | TXT
95000 7.50 FITS | TXT FITS | TXT FITS | TXT
95000 8.00 FITS | TXT FITS | TXT FITS | TXT
95000 8.50 FITS | TXT FITS | TXT FITS | TXT
95000 9.00 FITS | TXT FITS | TXT FITS | TXT
95000 9.50 FITS | TXT FITS | TXT FITS | TXT

Citations

Please remember to cite the appropriate paper(s) below and the DOI if you use these data in a published work. 

Note: These HLSP data products are licensed for use under CC BY 4.0.

References