LOFAR imaging capabilities and system sensitivity

This document describes the general astronomical capabilities of the LOw Frequency ARray (LOFAR). The frequency range covered by LOFAR is split into two bands denoted as low band (LB, 10 - 80 MHz) and high band (HB, 120 - 240 MHz). LOFAR stations are spread over a 100 km sized region in the northern part of the Netherlands. In addition to the Dutch stations there will be European stations providing baselines between 200 km and 1000 km. Most of the results in this document, however, are limited to the Dutch array. In section 2 the LBA and HBA station configurations are reviewed. Section 3 reviews the imaging capabilities as station Full Width Half Maximum, station Field of View, and array resolution. In section 4 the system sensitivity is considered and thermal noise levels in LOFAR images are given. Finally, in section 5 some cautionary notes are collected. We advise you to read these notes carefully before using the numbers that are presented in this report.