South Pole Collaboration Data Products at LAMBDA
The South Pole Collaboration made measurements of the CMB temperature at six frequencies from 0.82 to 7.5 GHz.
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South Pole Collaboration
- Measurements at six frequencies (0.82, 1.47, 2.0, 2.5, 3.8, 7.5 GHz) of the absolute difference
of antenna temperature ΔT between the sky at the zenith and a black body at Liquid Helium temperature. - Measurements of the atmospheric emission by a 90 GHz dedicated radiometer.
- Ground and Sun screens.
- Galactic, atmospheric, ground and sun signals measured by drift and zenith scans.
- Blend of extragalactic radio sources by (log N – log S) data in literature.
- TCMB = Tblack body + ΔT – Tgal - Texg - Tatm - Tground
- Black Body. <1 GHz: coaxial dummy load in a commercial LHe dewar; >1 GHz: Eccosorb in a 70 cm diameter LHe dewar.
- Corrugated horns: pyramidal at ν ≤ 3 GHz, conical at ν > 3 GHz, steerable between zenith (sky) and nadir (cold load) directions.
- Site : 1.6 km from the Amundsen Scott Base at South Pole (2820 m altitude, atm pressure : 524 ± 2 Hg mm).
Observation during local summer (December-January). - Participating institutions : Physics Dept – University of Milano – Italy - LBL – Berkeley (CA) - USA.
(see Antarctic Journal Review 1991, XXVI, 286 and Review 1993, XXVIII 306)
| Frequency (GHz) |
Rx Type | Antenna | Beam (HPBW) |
Receiver noise (K) |
Cold Load eff. temp. (a) |
|---|---|---|---|---|---|
| 0.82 | Differential (Dicke switch) Heterodyne |
Corrugated pyramidal horn |
18° x 23° | 55±2 | 9.69±0.42 (b) |
| 1.47 | Total power | Corrugated pyramidal horn |
30° x 27° | 53.5±0.04 | 3.854±0.023 (c) |
| 2.0 | Total power | Corrugated pyramidal horn |
20° x 23° | 118±4 | 3.855±0.040 (c) |
| 2.5 | Differential (Dicke switch) Heterodyne |
Corrugated pyramidal horn |
18° x 23° | 31±2 | 11.84±0.55 (b) |
| 3.8 | Direct RF gain total power |
Corrugated conical horn |
16° | 84±1 | 3.762±0.019 (c) |
| 7.5 | Direct RF gain total power |
Corrugated conical horn |
20°±2° | 234±3 | 3.671±0.023 (c) |
| 90(d) | Differential (Dicke switch) Heterodyne |
Corrugated conical horn |
7.5° x 7.5° | 1530±20 | n/a |
(a) Liquid Helium boiling temperature (3.842±0.002) K
(b) Coaxial dummy load
(c) Eccosorb absorber
(d) Used as atmospheric monitor in 1989 campaign
| Frequency (GHz) |
Antenna Temperature (K) |
Atmosphere Contribution (K) |
Ground Contribution (K) |
Sun Contribution (K) |
Galactic Contribution (K) |
Blend of Extragalactic Radiosources (K) |
|---|---|---|---|---|---|---|
| 0.820 ref. 1 | 6.7±1.5 | 0.90±0.35 | 0.03±0.05 | 0.08±0.08 | 2.67±0.33 | 0.34±0.07 |
| 1.47 ref. 2 and 4 | 3.971±0.096 | 1.08±0.08 | 0.06±0.03 | <0.01 | 0.82±0.19 | Modelled inside the galactic component |
| 2.0 ref. 3 and 4 | 3.95±0.05 | 1.07±0.07 | 0.05±0.04 | <0.01 | 0.33±0.10 | <0.03 |
| 2.5 ref. 1 | 3.73±0.15 | 1.155±0.300 | 0.03±0.05 | 0.000±0.005 | 0.118±0.025 | 0.016±0.005 |
| 3.8 ref. 5 | 3.653±0.008 | 1.109±0.004 | 0.006±0.008 | <0.001 | 0.055±0.015 | Modelled inside the galactic component |
| 7.5 ref. 6 | 3.544±0.045 | 1.222±0.064 | 0.022±0.015 | 0.008±0.004 | 0.007±0.004 | negligible |
| 90 ref. 7 | n/a | 8.4 – 10.3 | 0.030 | <0.001 | <0.001 | <0.001 |
| Frequency (GHz) | TCMB(a) (K) | Laboratory |
|---|---|---|
| 0.82 | 2.7±1.6 | Milano, Ref.1 |
| 1.47 | 2.26±0.20 | Berkeley Ref. 2 and 4 |
| 2.0 | 2.55±0.14 | Berkeley Ref. 3 and 4 |
| 2.5 | 2.50±0.34 | Milano Ref. 1 |
| 3.8 | 2.64±0.07 | Berkeley Ref. 5 |
| 7.5 | 2.69±0.07 | Berkeley Ref. 6 |
(a) Thermodynamic Temperature
(1) Sironi G. et al., 1991, ApJ 378, 550, ADS
(2) Bensadoun M. et al, 1993 ApJ 409,1, ADS
(3) Bersanelli M. et al., 1994, ApJ 424, 517, ADS
(4) Bersanelli M. et al. 1995, Astro. Lett. and Communications 32, 7, ADS
(5) De Amici G. et al., 1991, ApJ 381, 341, ADS
(6) Levin S. et al., 1992, ApJ 396, 3 ADS
(7) Bersanelli et al. 1995, ApJ 448, 8, ADS
