Ultra-faint Ultraviolet Galaxies at z~2 Behind the Lensing Cluster Abell 1689: the Luminosity Function, Dust Extinction and Star Formation Rate Density

Understand

We identified the z~2 Lyman break galaxies using deep HST ultraviolet (F275W/F336W) imaging of Abell 1689.

• Because of the imaging depth and the large magnification provided by the cluster, we detect galaxies 100x fainter (-19.5< M_1500 <-13) than previous surveys at this redshift.
• We are able to calculate the intrinsic sensitivity of the observations as a function of source plane position, allowing determinations of effective volume as a function of luminosity.
• We fit the faint-end slope of the luminosity function to be alpha = -1.74 +/-0.08, consistent with the values obtained for 2.5 < z < 6.