Subdwarf synthetic spectra to study hot components in old stellar populations

Abstract

We synthesized the integrated light of the old Galactic globular cluster NGC 2808 by using photometric data from HST as a proxy to quantify the contribution from each stellar component. To represent the stellar fluxes, we used the theoretical stellar library by Coelho (2014), supplemented by the one in Pacheco et al. (2021). The latter allows us to model the presence of hot high-gravity low-mass stars of the extended horizontal branch. The synthetic stellar fluxes were combined to produce a theoretical integrated light spectrum. In our modeling, the flux from the hot stellar population contributes approximately 25.2% in the near-UV band.