A Real-Time, All-Sky, High Time Resolution, Direct Imager for the Long Wavelength Array

Abstract

The future of radio astronomy will require instruments with large collecting areas for higher sensitivity, wide fields of view for faster survey speeds, and efficient computing and data rates relative to current capabilities. We describe the first successful deployment of the E-field Parallel Imaging Correlator (EPIC) on the LWA station in Sevilleta, New Mexico, USA (LWA-SV). EPIC is a solution to the computational problem of large interferometers. By gridding and spatially Fourier transforming channelised electric fields from the antennas in real-time, EPIC removes the explicit cross multiplication of all pairs of antenna voltages to synthesize an aperture, reducing the computational scaling from $\mathcal{O}(n_a^2)$ to $\mathcal{O}(n_g{\log }_2{n}_g)$, where $n_a$ is the number of antennas and $n_g$ is the number of grid points. Not only does this save computational costs for dense arrays but it produces very high time resolution images in real time. The GPU-based implementation uses existing LWA-SV hardware and the high performance streaming framework, Bifrost. We examine the practical details of the EPIC deployment and verify the imaging performance by detecting a meteor impact on the atmosphere using continuous all-sky imaging at 50 ms time resolution.

arXiv comment10 pages

References in corpus (16)

• Hydrogen Epoch of Reionization Array (HERA)
• The CHIME Fast Radio Burst Project: System Overview
• The non-coplanar baselines effect in radio interferometry: The W-Projection algorithm
• Observations of Fast Radio Bursts at Frequencies down to 400 Megahertz
• Correcting direction-dependent gains in the deconvolution of radio interferometric images
• The LWA1 Radio Telescope
• The first interferometric detections of Fast Radio Bursts
• Detection of Radio Emission from Fireballs
• Software Holography: Interferometric Data Analysis for the Challenges of Next Generation Observatories
• The Long Wavelength Array Software Library
• A Generic and Efficient E-field Parallel Imaging Correlator for Next-Generation Radio Telescopes
• Enabling Next Generation Dark Energy and Epoch of Reionization Radio Observatories with the MOFF Correlator
• Implementation of a Direct-Imaging and FX Correlator for the BEST-2 Array
• An Efficient Feedback Calibration Algorithm for Direct Imaging Radio Telescopes
• The Swarm Telescope Concept
• A Next Generation Low Band Observatory: A Community Study Exploring Low Frequency Options for ngVLA

Cited by in corpus (8)

• Data Analysis for Precision 21 cm Cosmology
• Redundant-Baseline Calibration of the Hydrogen Epoch of Reionization Array
• Broadband Imaging to Study the Spectral Distribution of Meteor Radio Afterglows
• Optimization and Commissioning of the EPIC Commensal Radio Transient Imager for the Long Wavelength Array
• Calibration Schemes with $\mathcal{O}(N\log N)$ Scaling for Large-N Radio Interferometers Built on a Regular Grid
• The impact of lunar topography on the 21-cm power spectrum for grid-based arrays : Insights for the Dark-ages EXplorer (DEX)
• Comparison of Fast, Hybrid Imaging Architectures for Multi-scale, Hierarchical Aperture Arrays
• Direct Wide-Field Radio Imaging in Real-Time at High Time Resolution using Antenna Electric Fields