ALBATROS
The ALBATROS Cosmology Experiment
Observations of redshifted 21-cm emission at ≤ 30 MHz are crucial for probing the cosmic dark ages in the history of the universe. The cosmic dark ages began after recombination and lasted until the birth of the first stars. Galactic foregrounds, human-made radio-frequency interference (RFI), and ionospheric interference pose challenges for low-frequency observations. Accurate measurement of the 21cm signal requires the development of precise foreground maps since Galactic foreground emissions are generally much brighter than the cosmological signal.
The Array of Long Baseline Antennas for Taking Radio Observations from the Sub-Antarctic/Seventy-ninth parallel ALBATROS is a cosmology experiment that will take high-resolution maps of the low-frequency radio sky. The interferometric array comprises autonomous antenna stations that store data for offline correlation. The antenna stations will have baseline lengths up to 20 km, allowing for an order of magnitude improvement in resolution compared to other low-frequency sky maps. The ALBATROS installation sites are selected to have minimal RFI and reduced ionospheric activity. We have installed ALBATROS instrumentation on Marion Island, the McGill Arctic Research Station (MARS), and Uapishka station. A dual-polarization dipole antenna, front-end electronics, back-end electronics, methanol fuel cell, solar hybrid power system, and a custom-designed data storage system are the building blocks of each antenna station. We employed the Long Wavelength Array (LWA) antenna and LWA front-end electronics (FEE) during the initial testing of the ALBATROS subsystems.
The impedance mismatch between the LWA antenna and the LWA FEE and the loss of antenna efficiency at low frequencies results in a drastic decrease in the observed Galactic signal below 30 MHz, necessitating the development of a new antenna and FEE optimized for operation in the sub-30 MHz frequency range. The work described in my master’s thesis presents the ALBATROS instrument design and recent development work on the first custom-made front-end electronics for ALBATROS, which will improve the low-frequency response of the instrument and set the stage for the first high-resolution maps of the low-frequency sky. The thesis also discusses the results from field tests conducted at Uapishka Station and MARS.
