1. Data analysis software
TNRT file format is MBFITS (Multi-Beam FITS; Muders, et al. 2006). We have a plan to convert the current file format to FITS (Flexible Image Transport System; Wells, Greisen & Harten, 1981) so that the TNRT file can be analyzed with world standard software. In parallel with the plan, we have developed data analysis scripts using Python libraries (e.g., NumPy (Harris et al. 2020); Astropy (Astropy Collaboration et al. 2013, 2018)).
We provide the Python scripts to each PI for TNRT data reduction. We have a plan to make the Python scripts publicly available.
2. Spectral line analysis procedures
Now, TNRT spectral line observation is conducted with the position switching. The obtained data are analyzed with the following procedures.
1. Sky subtraction: ρ = PtargetPsky − 1
2. Tsys* determination: Tsys* [K] = TnsPtarget+nsPtarget − 1 exp 𝜏0sinEl
3. Ta* determination: Ta* [K] = ρ × Tsys*
4. Unit conversion to Jansky [Jy]: Fν [Jy] = 2kAe(El) × Ta* × 1026
5. The correction of the Doppler effect
where Ptarget and Psky are radio power (linear scale) for target and sky, respectively. A noise source temperature (Tns) of the TNRT L-band receiver and the opacity at the zenith 𝜏0 are assumed to be 30.9 [K] and 0.0098, respectively, based on the "Status Report" of this web page. Ptarget+ns is radio power for target with the injection of noise source. The TNRT MBFITS file consists of sub scans and the noise source is injected for 0.25 % of each sub-scan integration time. Ae(El) is effective aperture area as a function of elevation (El) and k is the Boltzmann constant. Ae(El) applied here refers to the "Status Report" of 40-m TNRT. The Doppler effect at the TNRT site due to the earth's rotation and revolution can be corrected with the SkyCoord class of the Python library Astropy.
3. References
