EXTERNAL INSTRUMENT

BIGHORNS

The Broadband Instrument for Global HydrOgen ReioNisation Signal (BIGHORNS) is a total power radiometer developed to identify the signal from the Epoch of Reionisation in the all-sky averaged radio spectrum at low frequencies (70-300 MHz).

The Epoch of Reionisation (EoR) refers to an era of the universe where the previously neutral intergalactic medium was ionized by the first luminous sources. The observation of the 21cm transition line of neutral hydrogen is incredibly difficult for this period, but its detection is considered to be a vital goal for radio astronomy. To this end detection is being attempted with a range of systems from single antenna such as BIGHORNS to large interferometer arrays such as the MWA.

BIGHORNS is a conical log spiral antenna, deployed at the Murchison Radio-astronomy Observatory (MRO) in October 2014 and has been collecting data since then. Technical details of the original biconical antenna system and the later upgrades are presented by Sokolowski et al in the two 2015 papers, BIGHORNS - Broadband Instrument for Global Hydrogen Reionisation Signal and The Impact of the Ionosphere on Ground-based Detection of the Global Epoch of Reionisation Signal.

BIGHORNS has also been invaluable for monitoring radio frequency interference (RFI) at the future site of the low-frequency component of the Square Kilometre Array; see here and here.