Center for Astrophysics Research and Technologies Seminar Series
Demonstration and deployment of a fast, all-sky imaging architecture for large interferometer arrays in radio astronomy
Presented by Nithyanandan Thyagarajan (NRAO)
Radio astronomy is undergoing a transformation especially at low frequencies. Advances in technology will enable unprecedented amounts of collecting area and sensitivity, wide fields of view and high survey speeds, and high time-resolution. In particular, this will allow exploration of the history of the Universe through cosmic dawn and epoch of reionization (EoR) phases as well as mysterious explosive astrophysical phenomena. Many modern telescopes such as the Square Kilometre Array (SKA) are being designed to take advantage of these advances. This modern approach favors big, compact arrays with hundreds to thousands of antennas covering large collecting areas. However, it also brings formidable challenges of extreme data rates and enormous computational stress that scales in conventional approaches as the square of the number of antennas, $sim N_a^2$. I will present the E-field Parallel Imaging Correlator (EPIC) which implements a versatile and efficient algorithm for direct imaging. For large compact arrays, the computational cost scales much less strenuously as $sim N_a log N_a$ producing calibrated images at no extra cost while accommodating arbitrary layouts and even heterogeneous arrays. By design, it can operate at the Nyquist speed of incoming digitized data and hence can produce images even on microsecond timescales. Thus, it provides an ideal platform for building image-based fast transient search and monitoring systems for Fast Radio Bursts (FRB), millisecond pulsars (MSP), and other mysterious astrophysical events. EPIC holds significant advantage and promise for most modern compact radio interferometer arrays such as the Long Wavelength Array (LWA) stations, Hydrogen Epoch of Reionization Array (HERA), Canadian Hydrogen Intensity Mapping Experiment (CHIME), and cores of Murchison Widefield Array (MWA) and SKA1-low. I will demonstrate the performance of EPIC on data from LWA stations (LWA1, LWA-Sevilleta, and OVRO-LWA), and describe the plan to deploy a real-time GPU-version on the LWA station in Sevilleta (New Mexico). I will discuss the potential for expanding the scope to other large-N telescopes in the next decade.
2:00 pm, Thursday, March 29, 2018
PAIS-2540, PAIS
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