The APERTIF system increases the field of view of the original WSRT (left) by a factor 30 (right). ARTS builds on the APERTIF receivers to create an ultra-high time resolution, wide-field transient survey telescope. Shown fully right is the ARTS test detection of two pulsars at the edge of the 8.7 sq. deg. field. © NOVA.

APERTIF is a highly innovative receiver system that is currently being constructed for the Westerbork Synthesis Radio Telescope. Its factor 30 increase in field-of-view allows astronomers to survey the entire sky at 1.4 GHz with an unprecedented combination of sensitivity and speed. ARTS, the APERTIF Radio Transient System, extends this wide-field APERTIF system to high time resolution, enabling unique searches for millisecond transients, as well as nanosecond neutron-star timing. ARTS also allows for a wholly new approach to Very Long Baseline Interferometry (VLBI) that produces sensitive, wide-area images at milliarcsecond angular resolution.

The ARTS team represents all three NOVA science networks for research on radio transients and their likely origin: supernovae, neutron stars, and stellar-mass or supermassive black holes. The extreme energies, densities and gravity in these sources far exceed what can be produced in terrestrial laboratories. Their study is thus imperative for fundamentally understanding mass and energy. Through ARTS, we aim to understand how dense, hot matter is attracted and expelled in extreme gravity, to precisely measure stellar kinematics, and to determine supermassive black-hole energetics.

The I/O demands and compute power required for ARTS are extraordinary. The ARTS instrument algorithms, however, map exceedingly well on Graphics Processing Units (GPUs). ARTS is therefore being implemented as a GPU-based supercomputing instrument that will serve as a unique wide-field VLBI backend; as a pulsar timing machine much more powerful than PuMa II; and finally, as a next-generation fast-transient survey instrument. ARTS is an order of magnitude more sensitive to extragalactic radio bursts than any other experiment currently operating world-wide, including the Parkes telescope that recently found and confirmed these bursts. ARTS also provides much better localization, essential for discovering the nature of these enigmatic, powerful cosmological events.

The NOVA Instrumentation program funds part of a 500-TFLOPS GPU cluster for transient searching, pulsar timing, and wide-field VLBI. The NOVA funding also covers the salaries for a post-doctoral fellow plus 2 technical PhD students to develop and implement the GPU transient-search and pulsar-timing pipelines, and the program coordinator to oversee this effort at UvA. Thanks to the enabling funding provided by NOVA, significant external investment in ARTS has been secured.

Some additional information on ARTS can be found on the ASTRON website.

Principal investigator: Dr. Joeri van Leeuwen (ASTRON Dwingeloo).