Atacama Cosmology Telescope
(6 meter microwave survey telescope in Chile)
The Atacama Cosmology Telescope (ACT) is a six meter
microwave telescope on the Atacama Desert,
deployed in 2007, aimed a surveying the cosmic microwave background. It is aimable only
north-south, across 5 degrees, using the Earth's rotation to scan
across the other dimension.
Its aim has been identify distant galaxy clusters using the Sunyaev-Zel'dovich effect,
e.g., for further study using Sloan Digital Sky Survey, and to gather polarization
information useful for cosmology studies.
Its current receiver, AdvACT (for Advanced ACTPol),
is a set of arrays of transition edge sensor bolometers
covering bands ranging from 27GHz to 230GHz,
including some p, and to polarization-sensitive sensors,
with up to 1.4 arcminute angular resolution.
Earlier receivers covered a smaller frequency range,
the original receiver being MBAC (Millimeter bolometer array camera),
with three 32 × 32 grids, for 145 GHz, 215 GHz and 280 GHz.
In 2013, MBAC was replaced by ACTPol, for mapping CMB polarization,
with receivers for 90 GHz and 150 GHz
in its grids, each bolometer sensitive to polarization,
and which was used until 2015.
The instruments are designed for surveying, i.e., coverage of survey fields
of hundreds to thousands of square degrees, the surveys sometimes
referred to as the ACT Survey,
the ACTPol Survey, and the AdvACT Survey.
As the telescope is located in Chile, the coverage is generally in the
southern hemisphere. Locations were chosen so as to provide complimentary
coverage of some of the same regions covered by visible light surveys.
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|1.4mm||230GHz||951μeV||begin||Atacama Cosmology Telescope|
|11mm||27GHz||112μeV||end||Atacama Cosmology Telescope|
|ACT||ACT-CL J0102-4915||Atacama Cosmology Telescope||CL for "galaxy cluster"|
CMB Stage-4 (CMB-S4)