ACBAR detector array
Holzapfel Group | ACBAR | APEX | BICEP | BIMA Anisotropy | CBI | DASI | SZ Clusters | South Pole 'Scope | UCB Physics

Science Goals

Instrument Description

Project Team


2006 Data

2002 Data

[2002 Press Release]




Our cosmology findings are based on two maps we made of the CMB, using the Acbar receiver on the Viper telescope at the South Pole. These maps were made at a frequency of 150 GHz (wavelength = 2mm), where the cosmic microwave background radiation is at its brightest, using detectors (called bolometers) cooled to 0.25 Kelvin. These are the most sensitive high-resolution images of the CMB yet made.

CMB2: This picture shows the map made on the field we call "CMB2". The map is of a small patch of the southern sky well away from the plane of our Galaxy, approximately 6 degrees wide in Right Ascension by 3.5 degrees high in declination. The colors show where the CMB is hot and bright, vs. where it is cold and dim. In this map, the reds are hot and the blues are cold. Because the CMB photons last interacted with matter when the universe was 300,000 years old, this is a picture of the universe at that time, long before any galaxies formed. The hot and cold spots seen here are, in fact, the seeds from which structures like galaxies and clusters of galaxies will later form. The pattern of hot and cold spots is a random one; our scientific results come from the relative strength of structure on large vs. small scales in this map. The black squares in the map were cut from the data because of radio sources at those positions.

CMB2 map

(Click on the image for full size .jpg, or click here for postscript format)

CMB5: This map is much like the CMB2 map, but on a different patch of the sky. It is our most sensitive map, the one we spent the longest making.

CMB5 map

(Click on the image for full size .jpg, or click here for postscript format)

Copyright Holzapfel Group, 2002 Page last modified December 16, 2002