paper

J-PLUS: Understanding outlier white dwarfs in the third data release via dimensionality reduction

arXiv:2509.21304 · doi:10.1051/0004-6361/202555286

Abstract

We present the white dwarf catalog derived from the third data release of the Javalambre Photometric Local Universe Survey (J-PLUS DR3), which covers 3284 deg2 using 12 optical filters. A particular focus is given to the classification of outlier sources. We applied a Bayesian fitting process to the 12-band J-PLUS photometry of white dwarf candidates from Gaia EDR3. The derived parameters were effective temperature, surface gravity, and parallax. We used theoretical models from H- and He-dominated atmospheres, with priors applied to parallax and spectral type. From the posteriors, we derived the probability of an H-dominated atmosphere and of calcium absorption for each source. Outliers were identified as sources with chi2 > 23.2, indicating significant deviations from the best-fitting model. We analyzed the residuals from the fits using the UMAP technique, which enables the classification of outliers into distinct categories. The catalog includes 14844 white dwarfs with r < 20 mag and 1 < parallax < 100 mas, with 72% of the sources lacking spectroscopic (R > 500) classification. The application of UMAP identified three main types of outliers: random measurement fluctuations (391 sources), metal-polluted white dwarfs (98 sources), and two-component systems (282 sources). The last category also includes white dwarfs with strong carbon absorption lines. We validated the J-PLUS classifications by comparison with spectroscopy from SDSS and DESI, and with Gaia BP/RP spectra, confirming a one-to-one correspondence between J-PLUS photometric and spectroscopic classifications. The J-PLUS DR3 white dwarf catalog provides a robust dataset for statistical studies. The use of dimensionality reduction techniques enhances the identification of peculiar objects, making this catalog a valuable resource for the selection of interesting targets such as metal-polluted white dwarfs or binary systems.

18 pages, 22 figures. Published in Astronomy and Astrophysics. Catalog available at J-PLUS database and https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/701/A273

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