J-PLUS: Spectral evolution of white dwarfs by PDF analysis

Abstract

Aims. We estimated the spectral evolution of white dwarfs with effective temperature using the Javalambre Photometric Local Universe Survey (J-PLUS) second data release (DR2), which provides 12 photometric optical passbands over 2176 deg2. Methods. We analyzed 5926 white dwarfs with r ≤ 19.5 mag in common between a white dwarf catalog defined from Gaia EDR3 and J-PLUS DR2. We performed a Bayesian analysis by comparing the observed J-PLUS photometry with theoretical models of hydrogen- and helium-dominated atmospheres. We estimated the probability distribution functions for effective temperature (Teff), surface gravity, parallax, and composition; and the probability of having a H-dominated atmosphere (pH) for each source. We applied a prior in parallax, using Gaia EDR3 measurements as a reference, and derived a self-consistent prior for the atmospheric composition as a function of Teff. Results. We described the fraction of white dwarfs with a He-dominated atmosphere (fHe) with a linear function of the effective temperature at 5000 < Teff < 30 000 K. We find fHe = 0.24 ± 0.01 at Teff = 10 000 K, a change rate along the cooling sequence of 0.14 ± 0.02 per 10 kK, and a minimum He-dominated fraction of 0.08 ± 0.02 at the high-temperature end. We tested the obtained pH by comparison with spectroscopic classifications, finding that it is reliable. We estimated the mass distribution for the 351 sources with distance d < 100 pc, mass M > 0.45 M⊙, and Teff > 6000 K. The result for H-dominated white dwarfs agrees with previous studies, with a dominant M = 0.59 M⊙ peak and the presence of an excess at M ∼ 0.8 M⊙. This high-mass excess is absent in the He-dominated distribution, which presents a single peak. Conclusions. The J-PLUS optical data provide a reliable statistical classification of white dwarfs into H- and He-dominated atmospheres. We find a 21 ± 3% increase in the fraction of He-dominated white dwarfs from Teff = 20 000 K to Teff = 5000 K.

The miniJPAS survey: White dwarf science with 56 optical filters

“…The miniJPAS medium-band photometry permitted us to classify, with 99% confidence, the 11 white dwarfs in the sample correctly. The hydrogen Balmer lines are visible in miniJPAS photometry of H-dominated atmospheres with temperatures ranging from 7 000 K to 22 000 K. The lack of He-dominated white dwarfs in miniJPAS at T eff > 9 000 K can be circumvented thanks to the results obtained with J-PLUS by López-Sanjuan et al (2022). These authors analyzed 5 926 white dwarfs using a 12 passbands filter system (ugriz and seven medium bands) to derive the evolution with effective temperature in the fraction of He-dominated white dwarfs.…”

“…The second term corrects 3 arcsec photometry to 6 arcsec photometry and also depends on the position of the source in the CCD due to the variation of the point spread function along the FoV. The techniques and assumptions applied in the computation of these two aperture corrections are detailed in López-Sanjuan et al (2022).…”

“…The Bayesian methodology used to analyze the miniJPAS data was developed in López-Sanjuan et al (2022) to study the white dwarf population in the Javalambre Photometric Local Universe Survey (J-PLUS, Cenarro et al 2019), comprising 12 optical filters. We adapted the method to deal with the 56 medium bands in miniJPAS and we included the g and i broadbands in the analysis.…”

“…The u J and r broadbands were not used because they had been discarded from the final J-PAS observing strategy, which will only include g and i. In the following, we provide a summary of the fitting process, which is fully detailed in López-Sanjuan et al (2022).…”

“…The typical relative error in the effective temperature from miniJPAS data is 2%, which is close to the 1% estimated from spectroscopy. Additionally, the typical relative error for the general white dwarf population is 10% from Gaia DR3 photometry (Gentile Fusillo et al 2021) and 5% from J-PLUS photometry (López-Sanjuan et al 2022).…”