Sub-percent Photometry: Faint DA White Dwarf Spectophotometric Standards for Astrophysical Observatories

Understand

We have established a network of 19 faint (16.5 mag $< V < $19 mag) northern and equatorial DA white dwarfs as spectrophotometric standards for present and future wide-field observatories.

• Our analysis infers SED models for the stars that are tied to the three CALSPEC primary standards.
• Our SED models are consistent with panchromatic Hubble Space Telescope ($HST$) photometry to better than 1%.
• The excellent agreement between observations and models validates the use of non-local-thermodynamic-equilibrium (NLTE) DA white dwarf atmospheres extinguished by interstellar dust as accurate spectrophotometric references.