Starcounts in the Hubble Deep Field: Constraining Galactic Structure Models
摘要
Stellar sources are identified in the Hubble Deep Field, and accurate colours and magnitudes are presented. The predictions of a Galactic starcounts model are compared with the faint stellar counts in this field. The model reproduces the observations very well in the magnitude range 21.0 < V < 26.4, while it overpredicts the counts by a factor of four in the range 26.4 < V < 30.0. The luminosity function for halo objects must be a factor of two smaller than that predicted by an extrapolation of the solar-neighborhood luminosity function for disc stars (with 95% confidence level). This result, seen before in deep Hubble Space Telescope images of globular clusters, is therefore confirmed for the halo field population. The possible nature of a group of faint-blue objects is also investigated, concluding that they are most likely non-stellar. The possibility that they are QSOs is ruled out. If we insist upon their stellar nature, they would be halo white dwarfs, with either a very steep halo white dwarf luminosity function for Mv > +11.0, or a stellar density 0.4 times that of the disc white dwarfs in the solar-neighborhood.
引用
@article{arxiv.astro-ph/9607112,
title = {Starcounts in the Hubble Deep Field: Constraining Galactic Structure Models},
author = {R. A. Mendez and D. Minniti and G. de Marchi and A. Baker and W. J. Couch},
journal= {arXiv preprint arXiv:astro-ph/9607112},
year = {2015}
}
备注
Tex type, 7 pages, 3 postscript figures. Accepted for publication in Monthly Notices of the Royal Astronomical Society. A few typos corrected. Updated references. Note Added in Proof (including one table), containing a detailed photometric comparison (for point-like sources) between our results and those from other investigations of the HDF.