@article{0cf860d622dd48628807601bdd0dfab9,
title = "DAmodel: hierarchical Bayesian modelling of DA white dwarfs for spectrophotometric calibration",
abstract = "We use hierarchical Bayesian modelling to calibrate a network of 32 all-sky faint DA white dwarf (DA WD) spectrophotometric standards (16.5 < V < 19.5) alongside three CALSPEC standards, from 912 {\AA} to 32 μm. The framework is the first of its kind to jointly infer photometric zero points and WD parameters (surface gravity log g, effective temperature Teff, extinction AV , dust relation parameter RV ) by simultaneously modelling both photometric and spectroscopic data. We model panchromatic Hubble Space Telescope Wide Field Camera 3 (HST/WFC3) UVIS and IR photometry, HST/STIS UV spectroscopy, and ground-based optical spectroscopy to sub-per cent precision. Photometric residuals for the sample are the lowest yet yielding < 0.004 mag RMS on average from the UV to the NIR, achieved by jointly inferring time-dependent changes in system sensitivity and WFC3/IR count-rate nonlinearity. Our GPU-accelerated implementation enables efficient sampling via Hamiltonian Monte Carlo, critical for exploring the high-dimensional posterior space. The hierarchical nature of the model enables population analysis of intrinsic WD and dust parameters. Inferred spectral energy distributions from this model will be essential for calibrating the James Webb Space Telescope as well as next-generation surveys, including Vera Rubin Observatory{\textquoteright}s Legacy Survey of Space and Time and the Nancy Grace Roman Space Telescope.",
keywords = "methods: statistical, standards, stars: fundamental parameters, stars: statistics, surveys, white dwarfs",
author = "Boyd, \{Benjamin M.\} and Gautham Narayan and Mandel, \{Kaisey S.\} and Matthew Grayling and Abhijit Saha and Tim Axelrod and Thomas Matheson and Olszewski, \{Edward W.\} and Annalisa Calamida and Aaron Do and Bohlin, \{Ralph C.\} and Holberg, \{Jay B.\} and Ivan Hubeny and Susana Deustua and Armin Rest and Stubbs, \{Christopher W.\} and Aidan Berres and Mai Li and Mackenty, \{John W.\} and Elena Sabbi",
note = "Spectroscopic observations reported here were obtained at the Multiple Mirror Telescope (MMT) Observatory, a joint facility of the University of Arizona and the Smithsonian Institution. Spectra were also obtained at SOAR and at Gemini based in part on observations obtained at the Southern Astrophysical Research (SOAR) Telescope, which is a joint project of the Minist\textbackslash{}u00E9rio da Ci\textbackslash{}u00EAncia, Tecnologia e Inova\textbackslash{}u00E7\textbackslash{}u00F5es do Brasil (MCTI/LNA), the US National Science Foundation\textbackslash{}u2019s NOIRLab, the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU). Observations were also obtained at the international Gemini Observatory, a programme of NSF\textbackslash{}u2019s NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation on behalf of the Gemini Observatory partnership: the National Science Foundation (United States), National Research Council (Canada), Agencia Nacional de Investigaci\textbackslash{}u00F3n y Desarrollo (Chile), Ministerio de Ciencia, Tecnolog\textbackslash{}u00EDa e Innovaci\textbackslash{}u00F3n (Argentina), Minist\textbackslash{}u00E9rio da Ci\textbackslash{}u00EAncia, Tecnologia, Inova\textbackslash{}u00E7\textbackslash{}u00F5es e Comunica\textbackslash{}u00E7\textbackslash{}u00F5es (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). This work makes use of observations from the Las Cumbres Observatory global telescope network. This research has made use of the SVO Filter Profile Service \textbackslash{}u201CCarlos Rodrigo\textbackslash{}u201D, funded by MCIN/AEI/10.13039/501100011033/ through grant PID2023-146210NB-I00. BMB is supported by the Cambridge Centre for Doctoral Training in Data-Intensive Science funded by the UK Science and Technology Facilities Council (STFC) and two G-Research early career researchers grants used for equipment and travel. BMB also acknowledges travel support provided by Christ\textbackslash{}u2019s College Cambridge\textbackslash{}u2019s Clayton Fund, Legacy Survey of Space and Time Dark Energy Science Collaboration (LSST DESC) supported by The United States Department of Energy (DOE) funds administered by Stanford Linear Accelerator Center (SLAC) and STFC for UK participation in LSST through grant ST/S006206/1. BMB, AB, ML, and GN were supported on this project through the Hubble Space Telescope (HST) Guest Observer Programme (HST-GO-16764, PI G. Narayan). GN also gratefully acknowledges National Science Foundation (NSF) support from AST-2206195, and a CAREER grant AST-2239364, supported in-part by funding from Charles Simonyi, and OAC-2311355, DOE support through the Department of Physics at the University of Illinois, Urbana-Champaign (\#13771275), and HST-GO-17128 (PI R. Foley). Supernova and astrostatistics research at Cambridge University is supported by the European Union\textbackslash{}u2019s Horizon 2020 research and innovation programme under European Research Council Grant Agreement no. 101002652 (PI K. Mandel) and Marie Sk\textbackslash{}u0142odowska-Curie Grant Agreement no. 873089. CWS acknowledges support from Harvard University and the DOE cosmic frontier programme through award DE-SC0007881. EO was also partially supported by NSF grants AST-1815767 and AST-1313006. We acknowledge support from STSCI/HST: HST-GO-12967, HST-GO-13711, HST-GO-15113.",
year = "2025",
month = jun,
day = "1",
doi = "10.1093/mnras/staf629",
language = "English (US)",
volume = "540",
pages = "385--415",
journal = "Monthly Notices of the Royal Astronomical Society",
issn = "0035-8711",
publisher = "Oxford University Press",
number = "1",
}