The glow of primordial remnants

Abstract

We determine the expected surface brightness and photometric signature of a white dwarf remnant population, issued from primordial low-mass stars formed at high redshifts, in today galactic halos. We examine the radial dependence of such a contribution as well as its redshift dependence. Such a halo diffuse radiation is below the detection limit of present large field ground-based surveys, but should be observable with the HST and with the future JWST project. Since the surface brightness does not depend on the distance, the integration of several galactic dark halos along the line of sight will raise appreciably the chances of detection. Both the detection or the non-detection of such a remnant diffuse radiation within relevant detection limits offer valuable information on the minimum mass for star formation in the early universe and on the evolution of the stellar initial mass function.