A Catalog of Color - based Redshift Estimates for z < ∼ 4 Galaxies in the Hubble Deep Field

We derive simple empirical color-redshift relations for z < ∼ 4 galaxies in the Hubble Deep Field (HDF) using a linear function of three photometric colors (U − B, B − V , V − I). The dispersion between the estimated redshifts and the spectroscopically observed ones is small for relations derived in several separate color regimes; the dispersions range from σ z ≃ 0.03 to 0.1 for z < ∼ 2 galaxies, and from σ z ≃ 0.14 to 0.36 for z > ∼ 2 galaxies. We apply the color-redshift relations to the HDF photometric catalog and obtain estimated redshifts that are consistent with those derived from spectral template fitting methods. The advantage of these color-redshift relations is that they are simple and easy to use and do not depend on the assumption of any particular spectral templates; they provide model independent redshift estimates for z < ∼ 4 galaxies using only multi-band photometry. We provide a color-based estimated redshift catalog of HDF galaxies to z < ∼ 4. We use the estimated redshifts to investigate the redshift distribution of galaxies in the HDF; we find peaks in the redshift distribution that suggest large-scale clustering of galaxies to at least z ∼ 1 and that are consistent with those identified in spectroscopic probes of the HDF. – 2 –