Attaining Spectral Energy Distributions With Sub-Percent Uncertainties: All-Sky DA White Dwarf Spectrophotometric Standard Stars For Large Telescopes And Surveys.

Published

April 1, 2026

Author(s)

ABHIJIT SAHA, Edward W Olszewski, Benjamin M. Boyd, Thomas Matheson, Tim Axelrod, Gautham Narayan, Annalisa Calamida, Jay Holberg, Ivan Hubeny, ralph bohlin, Susana Deustua, Armin Rest, Jenna Claver, Sean Points, Christopher Stubbs, Elena Sabbi, John MacKenty

Abstract

This paper provides a synopsis of the project to establish thirty-two new faint (16.5 ≤ V ≤ 19.8) DA white16 dwarfs as spectrophotometric standards distributed over the whole sky. Our results validate the use of fully17 radiative pure hydrogen model fluxes for hot DA white dwarfs to predict the observed top of the atmosphere18 broadband fluxes from near ultraviolet through the near infrared to accuracies of a few parts per thousand.19 After fitting the line of sight reddenings simultaneously with the model spectral energy distributions of these20 stars against spectroscopic and multi-band photometric observations, we have shown that residuals have rms21 of typically 0.4 percent. This indicates that even the challenge from interstellar dust has been adequately met.22 Our stars supplement the three brighter DA white dwarfs that define the flux scale of CALSPEC. This level of23 photometric accuracy for these standard stars, their all sky coverage, and their brightness range that matches24 the dynamic range of large telescopes, constitutes an unprecedented ensemble of standard stars for both ground25 as well as space based use. In this paper, we target readers who may wish to use these as standard stars,26 and provide for them the essential content to understand their strengths and limitations, without having to27 traverse the technical details of analysis that are already captured in a series of papers since 2016. The textual28 narrative here describes the motivation, justification, and evolution of the analysis methods; describes the input29 data that constrain the modeling; as well as the stability and vulnerabilities of our results in the face of future30 improvements in models.

Citation

Astronomical Journal

Volume

171

Pub Type

Journals

Download Paper

https://doi.org/10.3847/1538-3881/ae4fac

Local Download

Keywords

White Dwarfs, Stars, Standards

Citation

Saha, A. , Olszewski, E. , Boyd, B. , Matheson, T. , Axelrod, T. , Narayan, G. , Calamida, A. , Holberg, J. , Hubeny, I. , Bohlin, R. , Deustua, S. , Rest, A. , Claver, J. , Points, S. , Stubbs, C. , Sabbi, E. and MacKenty, J. (2026), Attaining Spectral Energy Distributions With Sub-Percent Uncertainties: All-Sky DA White Dwarf Spectrophotometric Standard Stars For Large Telescopes And Surveys., Astronomical Journal, [online], https://doi.org/10.3847/1538-3881/ae4fac, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=961093 (Accessed September 26, 2026)

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