All-sky synthesis imaging for optimum transient detection in radio astronomy

We present the imaging subsystem of the AARTFAAC interferometric array, an All-sky monitor for detecting short term (seconds to minutes) transient activity of celestial radio sources in near real time. We optimize point source sensitivity, and reduce sidelobe confusion noise to significantly enhance transient detectability. The resulting images have a dynamic range of ∼2000∶1 with a 1 sec/90kHz integration at 60 MHz. They are confusion noise limited in few tens of seconds due to the ∼1deg Point Spread Function (PSF) of the instrument making the array the most sensitive dedicated transient detector at low frequencies.