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arXiv · astro-ph/9603020

Are Hubble Deep Field Galaxy Counts Whole Numbers?

Wesley N. Colley·James E. Rhoads·Jeremiah P. Ostriker·David N. Spergel
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Abstract

We compute the two-point angular correlation function and number-magnitude relation of Hubble Deep Field sources in order to assess their nature. We find that the correlation peaks between 0.25 arcsec and 0.4 arcsec with amplitude of 2 or greater, and much more for the smallest objects. This angular scale corresponds to physical scales of order 1 kpc for redshifts z > 1. The correlation must therefore derive from objects with subgalaxian separations. At faint magnitudes, the counts satisfy the relation Number prop. to 1/flux, expected for images which are subdivisions of larger ones. A conservative conjecture may explain these results. Since high redshift space (z > 0.5) dominates the volume of the sample, observational redshift effects are important. The K-correction and surface brightness dimming of diffuse sources enhances the prominence of compact, unresolved, UV-bright objects, such as star-forming regions within normal gas-rich galaxies. If such regions appear as individual sources, they could explain the subgalaxian correlation.

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Wesley N. Colley, James E. Rhoads, Jeremiah P. Ostriker, David N. Spergel. 1996-10-09. Are Hubble Deep Field Galaxy Counts Whole Numbers?. https://doi.org/10.1086/310394

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