ALMA - The Atacama Large Millimetre Array
23 Apr 2018



At an altitude of 5000m on the Atacama plateau in Northern Chile, ALMA is the worlds foremost (sub-)mm interferometer.




At an altitude of 5000m on the Atacama plateau in Northern Chile, ALMA is the worlds foremost (sub-)mm interferometer[1].  ALMA's main array consists of 50 12m telescopes positioned around the plateau which act together to simulate a larger telescope up to 16km wide. It also has a second array of 10 7m antennas which are able to see the larger scale structures missed by the main array, at lower resolution. Datasets from these arrays (and four similarly outfitted stand alone 12m antennas) can be combined to form detailed, high resolution observations of the cool gas and dust across the Universe[2].

ALMA's unprecedented resolution has revealed dust (and gas!) rings in multiple proto-stellar systems, and because it is orders of magnitude more sensitive than its predecessors, it has become an astro-chemical power-house, detecting emission from simple molecules in some of the earliest Galaxies to amazingly complex chemistry in nearby molecular clouds.

AlmaObs.pngThe complexity of ALMA, from setting up the antennas across the plateau to set the telescope's spatial resolution, to tuning the correlator to give simultaneous spectra in up to 16 different passbands, means observers need a tool designed to help them setup these observations.  The ALMA Observing Tool [3] was built, and is maintained at the UK ATC.  As part of the ALMA development plan, ESO has commissioned us to lead a prototyping study to redevelop the OT to modernise its underpinnings, and allow it to handle upcoming upgrades to the system.

The enormous volume of data coming from ALMA also requires a dedicated data analysis pipeline[4], a first for radio astronomy.  The ALMA Science Pipeline is part of the ALMA data reduction software package (CASA), led by NRAO, but with significant contributions from UK ATC software engineers.

The Applied Science group at RAL is working on astronomy with the manufacture of 60+ 1m diameter cryostats for the Atacama Large Millimetre Array (ALMA). These contain ten detector channels and incorporate a novel method for rapid integration and repair.​ For more information on the cryogenics and magnetics group, please click here.​