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information_for_astronomers:user_guide:reduction_of_spectroscopic_measurements
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information_for_astronomers:user_guide:reduction_of_spectroscopic_measurements [2018/12/12 14:51] ubach [Reprocessing spectra using the Class pipeline] |
information_for_astronomers:user_guide:reduction_of_spectroscopic_measurements [2018/12/12 16:18] (current) akraus |
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| - | ===== Reducing spectral line data ===== | + | ====== Reducing spectral line data ====== |
| The raw data (in MBFITS format) are converted to CLASS format automatically. This is done using the method described in Winkel, Kraus, & Bach, //Unbiased flux calibration methods for spectral-line radio observations//, [[http://adsabs.harvard.edu/abs/2012arXiv1203.0741W| A&A 540, A140, 2012]] (Section 3.4 and Section 4.5) - assuming a //constant system temperature// (Tsys) and //flat calibration signal// (Tcal). The latter is produced by a noise diode the power of which is in most cases directly fed into the waveguide within the receiver. //Neglecting the frequency-dependence of Tsys and Tcal introduces a bias, especially for wide-band observations!// (For more information see Winkel, Kraus, & Bach 2012 where we also show ways to do it better.) | The raw data (in MBFITS format) are converted to CLASS format automatically. This is done using the method described in Winkel, Kraus, & Bach, //Unbiased flux calibration methods for spectral-line radio observations//, [[http://adsabs.harvard.edu/abs/2012arXiv1203.0741W| A&A 540, A140, 2012]] (Section 3.4 and Section 4.5) - assuming a //constant system temperature// (Tsys) and //flat calibration signal// (Tcal). The latter is produced by a noise diode the power of which is in most cases directly fed into the waveguide within the receiver. //Neglecting the frequency-dependence of Tsys and Tcal introduces a bias, especially for wide-band observations!// (For more information see Winkel, Kraus, & Bach 2012 where we also show ways to do it better.) | ||
| The data files can be found on the //observer4// or //observer6// in the directory | The data files can be found on the //observer4// or //observer6// in the directory | ||
| - | **/daten/Class/class_YYYY_MM_DD.100m**. There might be a short delay until the data is processed and is visible in the class file after the observation has finished | + | **/daten/Class/[fw_]class_YYYY_MM_DD.100m**. There might be a short delay until the data is processed and is visible in the class file after the observation has finished |
| **Spectra in Class are always in units of Tcal!** To obtain Kelvins or Jy/Beam you have to multiply with the temperature of the noise diode (Tcal) and appropriate antenna sensitivities/efficiencies. Approximate values for this can be found on our receiver website [[http://www3.mpifr-bonn.mpg.de/div/effelsberg/receivers/receiver.html|receiver website]]. However, it is highly recommended to do calibration measurements during your observation for better accuracy. Furthermore, the automatic Class pipeline does not account for atmospheric opacity, elevation-gain curve, and antenna efficiency. Information about these steps can be found in Kraus 2009 (calibration memo). | **Spectra in Class are always in units of Tcal!** To obtain Kelvins or Jy/Beam you have to multiply with the temperature of the noise diode (Tcal) and appropriate antenna sensitivities/efficiencies. Approximate values for this can be found on our receiver website [[http://www3.mpifr-bonn.mpg.de/div/effelsberg/receivers/receiver.html|receiver website]]. However, it is highly recommended to do calibration measurements during your observation for better accuracy. Furthermore, the automatic Class pipeline does not account for atmospheric opacity, elevation-gain curve, and antenna efficiency. Information about these steps can be found in Kraus 2009 (calibration memo). | ||
| Line 14: | Line 14: | ||
| <code>bash</code> | <code>bash</code> | ||
| and source the init file:\\ | and source the init file:\\ | ||
| - | <code bash>source /opt/specpipeline2/init_classwriter.sh</code> | + | <code bash>source /opt/bin/init_rtsoft.sh</code> |
| afterward you can run | afterward you can run | ||
| <code bash>class</code> | <code bash>class</code> | ||
| Line 51: | Line 51: | ||
| <code bash> | <code bash> | ||
| - | source /opt/specpipeline2/init_classwriter.sh | ||
| source /opt/bin/init_rtsoft.sh | source /opt/bin/init_rtsoft.sh | ||
| </code> | </code> | ||
information_for_astronomers/user_guide/reduction_of_spectroscopic_measurements.1544622691.txt.gz ยท Last modified: 2018/12/12 14:51 by ubach
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