Table 3
Summary of errors in GBT H i spectral data.
| Error type | σa of T | Error in Wb, accumulated |
| (K) | from σ of T (K km s-1) | |
|
|
||
| Tsys noise | 0.25c | ... |
| line noise, σ(v) |
d
|
|
| baseline | 0.027 | 0.027NchΔv |
| stray | 0.07Tstray(v) | 0.07Wstray |
| scalee | 0.005T(v) | 0.005W |
Notes.
Error calculated for Nch channels with spacing Δv. Assuming that each W error is independent, the total W error is the sum of these, in quadrature.
Rms noise in antenna temperature (Ta) for 1 s of integration in a 1 km s-1 channel for two polarizations and in-band frequency switching.
Rms noise of Tmb in a 0.8 km s-1 channel for two polarizations. β = 0.16 for a single pointing and β = 0.11 for spectrum interpolated into the data cube. Integration times are t = 4 s for our scanning strategy (see Sect. 3). For long S6 and S8 integrations, t = 180 s (see Sect. 7.4). Tsys is approximately 20 K.
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