Speaker
Description
The axion, a proposed but not yet detected type of weakly interacting particle, remain one of the major candidates to constitute the elusive dark matter.
The shape of the white dwarf luminosity function (WDLF) is a powerful tool for constraining theoretical particles that would imply an additional cooling mechanism in white dwarfs (WDs).
We have used the observed WDLF derived from the 100-parsec GAIA DR3 sample and compared it with a theoretical counterpart, employing the McQub Monte Carlo method (Torres 2019) and WD models in which DFSZ-axion emission is computed self-consistently with the thermal structure of the WD. We verified that for the brightest WDs in the sample, with $M_{\tt Bol} < 10 \; {\tt dex}$, the $\chi^2$-tests are largely independent of the stellar formation rate (SFR), which represents the main source of uncertainty in theoretical WDLF calculations. We find that axion masses greater than $m_a \cos^2{\beta} > 6.5$ meV are disfavored, and that the $\chi^2$-tests yield increasingly worse null hypothesis probabilities as the axion mass increases from $0$ meV onward. This is an interesting result in light of previous works, such as Miller Bertolami (2014) and the references therein, where axion masses in the range $2.5 \; {\tt meV}
