The miniJPAS survey: White dwarf science with 56 optical filters

¹ Centro de Estudios de Física del Cosmos de Aragón (CEFCA), Unidad Asociada al CSIC, Plaza San Juan 1, 44001 Teruel, Spain
e-mail: clsj@cefca.es
² Department of Physics, University of Warwick, Coventry CV4 7AL, UK
³ Centro de Estudios de Física del Cosmos de Aragón (CEFCA), Plaza San Juan 1, 44001 Teruel, Spain
⁴ Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens, Penteli 15236, Greece
⁵ Instituto de Astrofísica de Andalucía, IAA-CSIC, Glorieta de la Astronomía S/N, 18008 Granada, Spain
⁶ Centro de Astrobiología (CSIC-INTA), ESAC Campus, Camino Bajo del Castillo S/N, 28692 Villanueva de la Cañada, Spain
⁷ Spanish Virtual Observatory, 28692 Villanueva de la Cañada, Spain
⁸ Departamento de Física, Universidade Federal de Sergipe, Av. Marechal Rondon S/N, 49100-000 São Cristóvão, Brazil
⁹ Observatório Nacional – MCTI (ON), Rua Gal. José Cristino 77, São Cristóvão, 20921-400 Rio de Janeiro, Brazil
¹⁰ Instituto de Física, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonalves, 9500 Porto Alegre, RS, Brazil
¹¹ Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Rd., Shanghai 200030, PR China
¹² Instituto de Física, Universidade de São Paulo, Rua do Matão 1371, 05508-090 São Paulo, Brazil
¹³ Donostia International Physics Centre (DIPC), Paseo Manuel de Lardizabal 4, 20018 Donostia-San Sebastián, Spain
¹⁴ IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
¹⁵ Instituto de Física, Universidade Federal da Bahia, 40210-340 Salvador, BA, Brazil
¹⁶ University of Michigan, Department of Astronomy, 1085 South University Ave., Ann Arbor, MI 48109, USA
¹⁷ University of Alabama, Department of Physics and Astronomy, Gallalee Hall, Tuscaloosa, AL 35401, USA
¹⁸ Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, 05508-090 São Paulo, Brazil
¹⁹ Instruments4, 4121 Pembury Place, La Canada Flintridge, CA 91011, USA

Received: 18 March 2022
Accepted: 10 July 2022

Abstract

Aims. We analyze the white dwarf population in miniJPAS, the first square degree observed with 56 medium-band, 145 Å in width optical filters by the Javalambre Physics of the accelerating Universe Astrophysical Survey (J-PAS), to provide a data-based forecast for the white dwarf science with low-resolution (R ∼ 50) photo-spectra.

Methods. We define the sample of the bluest point-like sources in miniJPAS with r <  21.5 mag, a point-like probability larger than 0.5, (u − r)< 0.80 mag, and (g − i)< 0.25 mag. This sample comprises 33 sources with spectroscopic information: 11 white dwarfs and 22 quasi-stellar objects (QSOs). We estimate the effective temperature (T_eff), the surface gravity, and the composition of the white dwarf population by a Bayesian fitting to the observed photo-spectra.

Results. The miniJPAS data are sensitive to the Balmer series and the presence of polluting metals. Our results, combined with those from the Javalambre Photometric Local Universe Survey (J-PLUS) which has a lower spectral resolution but has already observed thousands of white dwarfs, suggest that J-PAS photometry would permit – down to r ∼ 21.5 mag and at least for sources with 7000 <  T_eff <  22 000 K – both the classification of the observed white dwarfs into H-dominated and He-dominated with 99% confidence and the detection of calcium absorption for equivalent widths larger than 15 Å. The effective temperature is estimated with a 2% uncertainty, which is close to the 1% from spectroscopy. A precise estimation of the surface gravity depends on the available parallax information. In addition, the white dwarf population at T_eff >  7000 K can be segregated from the bluest extragalactic QSOs, providing a clean sample based on optical photometry alone.

Conclusions. The J-PAS low-resolution photo-spectra would produce precise effective temperatures and atmospheric compositions for white dwarfs, complementing the data from Gaia. J-PAS will also detect and characterize new white dwarfs beyond the Gaia magnitude limit, providing faint candidates for spectroscopic follow-up.