Vera C. Rubin LSST synthetic magnitudes derived from Gaia XP spectra
Year: 2026
Type: article
Abstract: Context. In the context of Milky Way studies, the Vera C. Rubin Observatory’s Legacy Survey of Space and Time is often described as a deep extension of the Gaia survey. In the future, joint analyses of the Gaia and LSST data promise to bring new insights into the Galaxy’s structure and formation history. However, the relatively small overlap in the magnitude ranges of the two surveys raises the question of how to perform a joint calibration of these datasets. Aims. We produce high-quality synthetic LSST photometry from Gaia XP low-resolution spectra and use SDSS and DES observed photometry to calibrate the spectra. Methods. We developed a method for empirically correcting Gaia XP spectra using SDSS Stripe 82 photometry. We projected sources for which Gaia XP data are available onto a magnitude–magnitude grid and calculated the residuals between uncorrected synthetic and observed SDSS magnitudes, which we then used to derive correction coefficients across spectral regions corresponding to each photometric band. Results. The correction significantly reduces systematic trends and scatter in the synthetic magnitudes: the median residuals decrease by an order of magnitude (e.g. for the u band the improvement is from 0.038 to 0.002 mag), and the standard deviation of residuals typically reduces by factor of 2 (e.g. for the u band from 0.2 to 0.07 mag). Conclusions. Our correction approach improves the reliability of synthetic photometry derived from Gaia XP spectra and enables a joint analysis of Gaia and LSST data for studies of Galactic structure and stellar populations.
Source: Astronomy and Astrophysics
Institutions: University of Nova Gorica, Ruđer Bošković Institute
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,865
Funders: National Science Foundation, Smithsonian Institution, U.S. Department of Energy, Alfred P. Sloan Foundation, Yale University, Carnegie Institution of Washington, Vanderbilt University, University of Pennsylvania, Ohio State University, University of Chicago, University of Michigan, University of Washington, Johns Hopkins University, Carnegie Mellon University, University of Notre Dame, University of Portsmouth, New Mexico State University, European Space Agency, York University, University College London, University of Oxford, European Commission, University of Nottingham, University of Sussex, Deutsche Forschungsgemeinschaft, École Polytechnique Fédérale de Lausanne, Ministério da Ciência, Tecnologia e Inovação, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Hrvatska Zaklada za Znanost, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, Financiadora de Estudos e Projetos, Universidad Nacional Autónoma de México, Institut de Física d'Altes Energies, Max-Planck-Institut für Astrophysik, Max-Planck-Institut für Astronomie, Instituto de Astrofísica de Canarias, University of Illinois at Urbana-Champaign, Office of Science, University of Colorado Boulder, Center for Cosmology and Astroparticle Physics, Ohio State University, HORIZON EUROPE Framework Programme, Leibniz-Gemeinschaft, European Regional Development Fund, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, Integrated Electronics Engineering Center, Binghamton University, Argonne National Laboratory, Fermilab, Lawrence Berkeley National Laboratory, H2020 Marie Skłodowska-Curie Actions, SLAC National Accelerator Laboratory
Awards: G1229526393, G1313983767, NSF's National Optical-Infrared Astronomy Research Laboratory (NOIRLab): Management and Operations of Vera C. Rubin Observatory, G1659327021, G1775808281, Construction of Vera C. Rubin Observatory under the Major Research Equipment and Facilities Construction (MREFC) Account, Final Design, Construction and Operations of Vera C. Rubin Observatory, G2371548206, G2380187409, G262532246, G303061748, Mining the Variable Sky, G3884951186, G4235786860, G4654690619, NSF's National Optical-Infrared Astronomy Research Laboratory (NOIRLab) as a Federally Funded Research and Development Center (FFRDC), G4711507462, G495301720, G498139845, Photometric Distance Estimation and Structure of the Milky Way Galaxy with Vera C. Rubin’s Legacy Survey of Space and Time, G5570207115, G618388848, G7286431674, G8382000481, G8945569637, G969889393
OpenAlex ID: W7203759164