RFI Survey in L and S Band for APSERa Cosmology Experiment

We present the results from an RFI (Radio Frequency Interference) survey conducted in the L-band and S-band, as a precursor to building the radio telescope for the APSERa (Array of Precision Spectrometers for the Epoch of RecombinAtion) cosmology experiment. The Epoch of Recombination (ERA) is a phase in the history of the universe, spanning the redshifts 900 < z < 8000, during which the first hydrogen and helium atoms formed. The photons from the recombination process result in additive distortions to the Cosmic Microwave Background spectrum.Feasibility studies have determined that an octave frequency range in the 2–6 GHz band is best suited for a ground-based detection of these cosmological recombination lines. APSERa seeks to detect the same. To determine the potential sites for APSERa, we have developed and deployed a RFI survey system operating in the 500 MHz - 6.5 GHz band across multiple locations in India. The results from the RFI analysis are presented in this paper.