White Mountain Collaboration Data Products at LAMBDA
The White Mountain Collaboration made measurements of the CMB temperature at five frequencies from 2.5 to 90 GHz.
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White Mountain Observations
- Measurements of the absolute difference ΔT between the antenna temperatures of the sky at the zenith (antenna upward) and a black body at Liquid Helium temperature (antenna downward) at five frequencies: 2.5 , 4.75, 10, 33 and 90 GHz.
- Heterodyne radiometers can be moved along a rail and set above a black body source (optically thick Eccosorb target covered by Liquid Helium at ambient pressure in a 70 cm diameter dewar)
- Geometrically scaled, corrugated horns tiltable between zenith (sky) and nadir (cold load) directions. When looking down the horn circular mouth can be attached to the dewar mouth
- Atmospheric and galactic foregrounds measured by zenith and drift scans
- A separate 9.4 GHz radiometer entirely dedicated to simultaneous studies of the atmospheric emission
- Observations from University of California White Mt. Research Station (3800 m altitude)
- Participating institutions
2.5 GHz : Physics Dept. – University of Milano – Italy
4.75 GHz : Istituto TESRE – CNR – Bologna – Italy
9.4 GHz : Haverford College - Haverford (Pa) – USA
10 GHz : LBL – Berkeley (Ca) – USA
33 GHz : LBL – Berkeley (Ca) – USA
90 GHz : LBL – Berkeley (Ca) – USA
---- : Physics Dept. – University of Padova - Italy
(see Smoot, G.F. et al. 1983, Phys.Rev.Lett. 51, 1099 ADS, and Smoot, G.F. et al. 1985, Ap.J., 291, L23 ADS)
| Frequency (GHz) |
System bandwidth (GHz) |
Antenna Half-power beam width (deg) |
System noise (K/Hz1/2) |
Laboratory (Ref) |
|---|---|---|---|---|
| 2.5 | 0.160 | 12.5 | 0.2 | Milano (1) |
| 4.75 | 0.160 | 12.5 | 0.1 | Bologna (2) |
| 9.4(*) | 1 | 12.6 | 0.1 | Haverford (3,4) |
| 10.0 | 0.910 | 12.5 | 0.05 | Berkeley (5) |
| 33.0 | 1 | 7.5 | 0.08 | Berkeley (6) |
| 90.0 | 2 | 7.5 | 0.1 | Berkeley (7) |
(*) entirely dedicated to study the atmospheric emission
(1) Sironi G. and Bonelli G., 1986, ApJ, 311, 418
(2) Mandolesi N. et al 1986, Ap.J. 310, 561
(3) Partridge R.B. et al., 1984, Phys.Rev. D, 29, 2683
(4) Danese L. and Partridge R.B., 1989, ApJ 342, 604
(5) Kogut A. et al., 1988, ApJ, 325, 1
(6) De Amici G. et al., 1985, ApJ , 298, 210
(7) Witebsky C. et al., 1986, ApJ, 310, 145
| Frequency (GHz) |
Eccosorb (o) (mK) |
Windows + gas (mK) |
Dewar walls (mK) |
Reflected signals (mK) |
Total (mK) |
|---|---|---|---|---|---|
| 2.5 | 3716±4 | 4±2 | 1209±210 (a) 1458±120 (b) |
70±25 (a) 340±50 (b) |
4999±212 (a) 5518±130 (b) |
| 4.75 | 3663±4 | 5±2 | 8±7 | 40±30 (a) 6±4 (b) |
3716±31 (a) 3682±10 (b) |
| 10 | 3541±4 | 5±2 | 9±5 | 7±4 | 3562±10 |
| 33 | 3039±4 | 4±2 | 5±5 | 20±6 | 3068±9 |
| 90 | 2020±4 | 18±3 | 10±10 | 35±35 | 2083±37 |
(o) Eccosorb/Liquid Helium physical temperature 3776±4 mK,
(a) 1982 value,
(b) 1983 value
| Frequency (GHz) |
TA,load (mK) |
ΔT (sky-load) (mK) |
ΔToffset (mK) |
Tground (mK) |
Tatmosphere (mK) |
TGalaxy (mK) |
Year |
|---|---|---|---|---|---|---|---|
| 2.5 | 4999±212 5518±130 |
-1401±100 -1557±58 |
(a) (a) |
12±10 6±10 |
950±50 950±50 |
148±30 200±30 |
1982 1983 |
| 4.75 | 3716±31 3682±10 |
940±80 -45±13 |
960±160 0±20 |
30±10 20±20 |
1000±100 997±70 |
40±30 35±25 |
1982 1983 |
| 9.4 | -- -- |
-- -- |
-- -- |
30±10 8±5 |
1030±30 103±30 |
<30±10 <10±5 |
1982 1983 |
| 10 | 3562±10 | 57±4 43±7 |
0±40 0±30 |
0±3 0±3 |
930±160 1200±130 |
3±3 4±2 |
1982 1983 |
| 33 | 3068±9 | 3860±40 3540±30 |
-100±50 -30±30 |
1±1 1±1 |
4850±140 4530±90 |
1±1 1±1 |
1982 1983 |
| 90 | 2083±17 | 11340±60 8780±37 |
0±300 10±9 |
1±1 1±1 |
12600±590 9870±90 |
0±1 0±1 |
1982 1983 |
(a)included in TA,load
| Frequency (GHz) |
Number of observations |
CMB antenna temperature (K) |
CMB thermodynamic temperature (K) |
Combined 1982 and 1983 results (K) |
|---|---|---|---|---|
| 2.5 | 6 18 |
2.48±0.14 2.81±0.07 |
2.54±0.14 2.87±0.07 |
2.79±0.15 Ref.1 |
| 4.75 | 5 38 |
2.63±0.21 2.59±0.08 |
2.73±0.22 2.70±0.07 |
2.70±0.07 Ref.2 |
| 10 | 82 59 |
2.43±0.12 2.40±0.14 |
2.66±0.12 2.63±0.14 |
2.65±0.09 Ref.5 |
| 33 | 21 32 |
2.10±0.20 2.09±0.13 |
2.82±0.21 2.81±0.14 |
2.81±0.12 Ref.6 |
| 90 | 29 49 |
1.00±0.57 0.99±0.09 |
2.58±0.79 2.57±0.12 |
2.57±0.12 Ref.7 |
For Columns 2-4, the first row is for 1982 data and the second row is for 1983 data.
