Absolving the SSINS of Precision Interferometric Radio Data: A New Technique for Mitigating Ultra-faint Radio Frequency Interference
We introduce a new method for mitigating ultra-faint radio frequency interference (RFI), which we call Sky-Subtracted Incoherent Noise Spectra (SSINS). SSINS is designed to identify and remove RFI below the single baseline thermal noise. We demonstrate the capabilities of SSINS using the Murchison Widefield Array (MWA) in Western Australia. Using SSINS, we successfully imaged aircraft flying over the array via digital television (DTV) reflection. We also made SSINS-informed data cuts to substantially improve an MWA Epoch of Reionization power spectrum limit. We describe how to use SSINS with new data. SSINS is publicly available, and we have constructed comprehensive usage tutorials and documentation.