Constraining the luminosity function of faint undetected i-dropout galaxies

Understand

We present a new technique to quantify the light contribution coming from the faint high redshift ($z\sim6$) galaxies below the detection threshold of imaging data, set conventionally at S/N=4.5.

• We illustrate the technique with an application to Hubble Space Telescope Advanced Camera for Surveys images in the F775W and F850LP filters of the Ultra Deep Field parallel field NICP12.
• The aim of this analysis is to extend by a few magnitudes the faint end of the luminosity function at $z\sim6$.
• After masking all the detected sources in the field we apply a Fast Fourier Transform to obtain the spatial power spectrum of the background signal.