Apparent radio transients mapping the near-Earth plasma environment
arXiv:2003.11138 · doi:10.1093/mnras/stab1156
Abstract
We report the discovery of bright, fast, radio flashes lasting tens of seconds with the AARTFAAC high-cadence all-sky survey at 60 MHz. The vast majority of these coincide with known, bright radio sources that brighten by factors of up to 100 during such an event. We attribute them to magnification events induced by plasma near the Earth, most likely in the densest parts of the ionosphere. They can occur both in relative isolation, during otherwise quiescent ionospheric conditions, and in large clusters during more turbulent ionospheric conditions. Using a toy model, we show that the likely origin of the more extreme (up to a factor of 100 or so) magnification events likely originate in the region of peak electron density in the ionosphere, at an altitude of 300-400 km. Distinguishing these events from genuine astrophysical transients is imperative for future surveys searching for low frequency radio transient at timescales below a minute.
arXiv comment11 pages, 10 figures. Accepted by MNRAS
References in corpus (23)
- Astropy: A Community Python Package for Astronomy
- The NumPy array: a structure for efficient numerical computation
- The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
- LOFAR: The LOw-Frequency ARray
- A New Electron Density Model for Estimation of Pulsar and FRB Distances
- The Last of FIRST: The Final Catalog and Source Identifications
- The Very Large Array Low-frequency Sky Survey Redux (VLSSr)
- The Gaussian Plasma Lens in Astrophysics. Refraction
- Multisource Self-calibration for Sensor Arrays
- The effect of the ionosphere on ultra-low frequency radio-interferometric observations
- LOFAR MSSS: Detection of a low-frequency radio transient in 400 hrs of monitoring of the North Celestial Pole
- A survey for transients and variables with the Murchison Widefield Array 32-tile prototype at 154 MHz
- Surveying the Dynamic Radio Sky with the Long Wavelength Demonstrator Array
- New methods to constrain the radio transient rate: results from a survey of four fields with LOFAR
- Extreme scattering events from axisymmetric plasma lenses
- New Limits on the Low-frequency Radio Transient Sky Using 31 hr of All-sky Data with the OVRO-LWA
- Detection of a Low-frequency Cosmic Radio Transient Using Two LWA Stations
- Long-term study of extreme giant pulses from PSR B0950+08 with AARTFAAC
- Density duct formation in the wake of a travelling ionospheric disturbance: Murchison Widefield Array observations
- AARTFAAC Flux Density Calibration and Northern Hemisphere Catalogue at 60 MHz
- The Murchison Widefield Array Transients Survey (MWATS). A search for low frequency variability in a bright Southern hemisphere sample
- The AARTFAAC 60 MHz transients survey
- A LOFAR Observation of Ionospheric Scintillation from Two Simultaneous Travelling Ionospheric Disturbances