Table 2
GBT and NRT half-power beam widths (HPBWs) and efficiencies.
| Facility | Frequency (GHz) | θHPBW (′) | ηA | ηmB |
|---|---|---|---|---|
| GBT | 1.67 | 7.55 ± 0.083 | 0.72(a) | 0.95(b) |
| GBT | 23.8 | 0.53 ± 0.005 | 0.68(a) | 0.91(b) |
| NRT | 1.67 | 3.5 × 19 | 0.46 | 0.65(c) |
Notes. (a) Aperture efficiency (ηA) from the GBO Proposer’s Guide for the GBT of 3 January 2023. (b)Main beam efficiency deduced from ηmB = ηAStelΩ/λ2, where Stel is the GBT surface telescope area (7854 m2), À is the wavelength, and Ω is the solid angle of the Gaussian beam defined by the HPBW in radians, which is given by 
. (c) Assuming a conversion factor of 0.85 K Jy−1 and an effective area of 7000 m2.
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