Galaxy Number Counts and Implications for Strong Lensing

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We compare galaxy number counts in HST/ACS fields containing moderate-redshift (0.2<z<1.0) strong gravitational lenses with those in two control samples: (1) the first square degree of the COSMOS survey, comprising 259 ACS fields and (2) 20 &#34;pure parallel&#34; fields randomly located on the sky.

• Through a Bayesian analysis we determine the expectation values (mu_0) and confidence levels of the underlying number counts for a range of apertures and magnitude bins.
• Our analysis has produced the following results: (i) We infer that our control samples are not consistent, with the number counts in the COSMOS sample being significantly higher than in the pure parallel sample for 21 <= F814W <= 23.
• This result matches those found in previous analyses of COSMOS data using different techniques.