J/A+A/691/A211 J-PLUS DR2 white dwarfs calcium absorption (Lopez-Sanjuan+, 2024)
J-PLUS: The fraction of calcium white dwarfs along the cooling sequence.
Lopez-Sanjuan C., Tremblay P.-E., O'Brien M.W., Spinoso D., Ederoclite A.,
Vazquez Ramio H., Cenarro A.J., Marin-Franch A., Civera T., Carrasco J.M.,
Gaensicke B.T., Gentile Fusillo N.P., Hernan-Caballero A., Hollands M.A.,
del Pino A., Dominguez Sanchez H., Fernandez-Ontiveros J.A.,
Jimenez-Esteban F.M., Rebassa-Mansergas A., Schmidtobreick L., Angulo R.E.,
Cristobal-Hornillos D., Dupke R.A., Hernandez-Monteagudo C., Moles M.,
Sodre L.Jr, Varela J.
<Astron. Astrophys. 691, A211 (2024)>
=2024A&A...691A.211L 2024A&A...691A.211L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, white dwarf; Effective temperatures; Stars, masses
Keywords: methods: statistical - techniques: photometric - white dwarfs
Abstract:
We used the Javalambre Photometric Local Universe Survey (J-PLUS)
second data release (DR2) photometry in 12 optical bands over
2176deg2 to estimate the fraction of white dwarfs with the presence
of Ca II H+K absorption along the cooling sequence. We compared the
J-PLUS photometry against metal-free theoretical models to estimate
the equivalent width in the J0395 passband of 10nm centered at 395nm
(EWJ0395), a proxy to detect calcium absorption. A total of 4399 white
dwarfs with effective temperatures within 30000>Teff>5500K and
masses of M>0.45M☉ were analyzed. Their EWJ0395 distribution was
modeled using two populations, corresponding to polluted and
non-polluted systems, to estimate the fraction of calcium white dwarfs
(fCa) as a function of Teff. The probability of each individual white
dwarf presenting calcium absorption, pca, was also computed. The
comparison of EWJ0395 with both the measured Ca/He abundance and the
identification of metal pollution from spectroscopy shows that EWJ0395
correlates with the presence of Ca II H+K absorption. The fraction of
calcium white dwarfs changes along the cooling sequence, increasing
from fCa∼0 at Teff=13500K to fCa∼0.15 at Teff=5500K. This trend
reflects the selection function of calcium white dwarfs in the
optical. We compare our results with the fractions derived from the
40pc spectroscopic sample and from Sloan Digital Sky Survey (SDSS)
spectra. The trend found in J-PLUS observations is also present in the
40pc sample; however, SDSS shows a deficit of metal-polluted objects
at Teff<12000K. Finally, we found 39 white dwarfs with pca>0.99.
Twenty of them have spectra presented in previous studies, whereas we
obtained follow-up spectroscopic observations for six additional
targets. These 26 objects were all confirmed as metal-polluted
systems.The J-PLUS optical data provide a robust statistical
measurement for the presence of Ca II H+K absorption in white dwarfs.
We find a 15±3% increase in the fraction of calcium white dwarfs
from Teff=13500K to 5500K, which reflects their selection function in
the optical from the total population of metal-polluted systems.
Description:
The catalog presents the inferred atmospheric parameters, calcium
equivalent width, and calcium probability for the 5926 white dwarfs
with r<19.5mag in common between the white dwarf catalog defined
from Gaia EDR3 in Gentile Fusillo et al. (2021MNRAS.508.3877G 2021MNRAS.508.3877G, Cat.
J/MNRAS/508/3877) and J-PLUS DR2 (Lopez-Sanjuan et al.,
2022A&A...658A..79C 2022A&A...658A..79C, Cat. J/A+A/658/A79). The J-PLUS twelve-band
photometry but J0395 is compared with theoretical models to derive the
probability density functions (PDFs) for the effective temperature
(Teff) and the mass by assuming H- and He-dominated atmospheres. We
used pure-H models to describe H-dominated atmospheres (Tremblay et
al., 2011ApJ...730..128T 2011ApJ...730..128T, Cat. J/ApJ/730/128, 2013A&A...559A.104T 2013A&A...559A.104T),
while mixed models with H/He=10-5 at Teff>6500K and pure-He models
at Teff<6500K were used to describe He-dominated atmospheres
(Cukanovaite et al., 2018MNRAS.481.1522C 2018MNRAS.481.1522C, 2019MNRAS.490.1010C 2019MNRAS.490.1010C). The
mass-radius relation of Fontaine et al. (2001PASP..113..409F 2001PASP..113..409F) for
thick (H-atmospheres) and thin (He-atmospheres) hydrogen layers was
assumed in the modeling. We obtained the summary statistics for each
parameter by marginalizing the PDFs over the other parameters and
performing a Gaussian fit to the resulting distribution. The reported
parameters and their uncertainties are the median and the dispersion
of the best-fitting Gaussian. We compared the expected flux in the
filter J0395 from the modelling with the observed one to obtain the
equivalent width in the J0395 passband, EWJ0395. This values are used
to model the population of calcium white dwarfs and to infer the
probability of presenting calcium absorption, pca.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
wdpca.dat 80 5926 Atmospheric parameters and calcium absorption
for J-PLUS DR2 white dwarfs
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See also:
J/ApJ/730/128 : Spectroscopy of DA WD from the SDSS-DR4 (Tremblay+, 2011)
J/MNRAS/508/3877 : Catalogue of white dwarfs in Gaia EDR3 (Gentile+, 2021)
J/A+A/658/A79 : J-PLUS white dwarf atmospheric parameters
(Lopez-Sanjuan+, 2022)
http://archive.cefca.es/catalogues/jplus-dr2 : J-PLUS DR2 Home Page
Byte-by-byte Description of file: wdpca.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- TileID Identifier of the J-PLUS Tile image in the
r band where the object was detected
7- 12 I6 --- NUMBER Number identifier assigned by SExtractor
for the object in the r-band image
14- 21 F8.4 deg RAdeg Right ascension (J2000)
23- 29 F7.4 deg DEdeg Declination (J2000)
31- 35 F5.3 --- pca Probability of having calcium absorption
37- 43 F7.2 0.1nm EWJ0395 Equivalent width in the J0395 passband
45- 50 F6.2 0.1nm e_EWJ0395 Uncertainty in EWJ0395
52- 59 F8.1 K Teff Effective temperature
61- 68 F8.1 K e_Teff Uncertainty in Teff
70- 74 F5.3 Msun Mass Mass
76- 80 F5.3 Msun e_Mass Uncertainty in mass
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Acknowledgements:
Carlos Lopez San Juan, clsj(at)cefca.es
(End) Carlos Lopez San Juan [CEFCA], Patricia Vannier [CDS] 08-Nov-2024