Lawrence Herman | Searcharxiv

arXiv2026

Continuous Ultra-Low-Frequency Solar Radio Monitoring with ALBATROS from the High Arctic

In the Canadian High Arctic, nearly five months of continuous daylight enable uninterrupted low-frequency solar monitoring. We present the first solar science results from the Array of Long Baseline Antennas for Taking Radio Observations from Seventy-Ninth Parallel (ALBATROS). This broadband radio array is designed to explore the largely uncharted radio sky below 30 MHz, where polar ionospheric conditions permit access to frequencies rarely accessible from ground-based sites. Using observations spanning 1-125 MHz, we detect bright solar radio bursts exhibiting complex spectral and polarised structure. The bursts are observed simultaneously by all eight autonomous stations, demonstrating the stability and consistency of the array. Comparison with concurrent soft X-ray measurements reveals a strong temporal correlation between the radio and X-ray emission. These observations establish ALBATROS as a new facility for ultra-low-frequency solar monitoring, opening a new window on solar radio bursts, space weather, and the dynamic heliosphere.

astro-ph.IM↗

arXiv2024

Drone-Based Antenna Beam Calibration in the High Arctic

Precision calibration is a critical requirement for future ultra-low-frequency observations of the early universe. The Array of Long Baseline Antennas for Taking Radio Observations from the Seventy-Ninth Parallel (ALBATROS), a radio interferometer located in the Canadian high Arctic, is designed to map Galactic foreground emission as a pathfinder for these future experiments. Accurate antenna beam characterization at these frequencies is therefore essential, yet remains uniquely challenging. We present PteroSoar, a custom-built drone platform equipped with a calibrated radio-frequency transmitter that enables controlled, in-situ measurements of low-frequency antenna beams. As an initial demonstration, we produce a two-dimensional beam map of an ALBATROS antenna at 50~MHz to a precision of approximately $10\%$ near zenith. We identify the dominant sources of systematic uncertainty, including timing imprecision, and outline hardware and software improvements that are expected to reduce beam measurement uncertainties to below $5\%$. This target is sub-dominant to the $\sim20\%$ amplitude variability introduced by ionospheric scintillation at these frequencies, providing a practical pathway toward precision beam calibration for ALBATROS and other ultra-low-frequency radio experiments.

astro-ph.IM↗