Extending the population synthesis method to isolated young cooling white dwarfs we are able to confront our model assumptions with observations made in ROSAT All-Sky Survey (Fleming et al., 1996). This allows us to check model parameters such as evolution of spectra and separation of heavy elements in DA WD envelopes. It seems like X-ray spectrum temperature of these objects is given by the formula T_{X-ray} = min(T_eff, T_max). We have obtained DA WD's birth rate and upper limit of the X-ray spectrum temperature: DA birth rate =0.61×10−12 in cubic parsec per year and T_max = 41000 K. These values are in good correspondence with values obtained by other authors (Liebert et al., 2004; Wolff et al., 1996). From this fact we also conclude that our population synthesis method is applicable to the population of close-by isolated cooling white dwarfs as well as to the population of the isolated cooling neutron stars.
@article{arxiv.1009.6102,
title = {Population synthesis of DA white dwarfs: constraints on soft X-ray spectra evolution},
author = {P. A. Boldin and V. F. Suleimanov and S. I. Blinnikov and S. B. Popov},
journal= {arXiv preprint arXiv:1009.6102},
year = {2015}
}