Calibration

Since BEARS is operated in DSB mode, you must calibrate the difference of sideband ratio among receiver channels. NRO provides the calibration data for the spectral lines (rest frequency) included in the accepted proposals. If possible, we recommend that observers get the calibration data by themselves during their observing time.

How to calibrate

[step 0] Please look for a standard position where line intensity is strong enough to achieve good signal-to-noise ratio with a short integration time, because the accuracy of calibration depends on the signal-to-noise ratio.
[step 1] Observe the standard position using S100. This receiver is equipped with an SSB filter. This receiver can observe the same frequency range. Beam size is almost the same as BEARS.
[step 2] Observe the standard position using all receiver channels of BEARS.
[step 3] Analyze data and get the scaling factor for each receiver channel. In NOSTAR or NEWSTAR (our reduction software systems), apply the scaling factor to data.

Calibration data -Valid for 2011.12-2012.5

Calibration data for this season (2011.12-2012.5) are available here. We supply calibration data for some spectral lines;¹²CO 1-0 (USB), ¹³CO 1-0 (LSB), C¹⁸O 1-0 (LSB), H¹³CO⁺ 1-0 (LSB), and CS 2-1 (LSB) at the rest frequency of each line.

Calibration data -Valid for 2010.12-2011.5

Calibration data for this season (2010.12-2010.5) are available here. We supply calibration data for some spectral lines;¹²CO 1-0 (USB), ¹³CO 1-0 (LSB), C¹⁸O 1-0 (LSB), H¹³CO⁺ 1-0 (LSB), and SiO 2-1 (LSB) at the rest frequency of each line.

Calibration data -Valid for 2009.12-2010.5

Calibration data for this season (2009.12-2010.5) are available here. Now we supply calibration data for some spectral lines;¹² CO 1-0 (USB), ¹³CO 1-0 (LSB), C¹⁸O 1-0 (LSB), H¹³CO⁺ (LSB), and N₂H⁺ (LSB) at the rest frequency of each line.

Calibration data -Valid for 2008.12-2009.5

Calibration data for this season (2008.12-2009.5) are available here. Now we supply calibration data for some spectral lines; CO 1-0 (USB), ¹³CO 1-0 (LSB), C¹⁸O 1-0 (LSB), HCN 1-0 (LSB), HCO⁺ 1-0 (LSB), H¹³CN 1-0 (LSB), H¹³CO⁺ 1-0 (LSB), and CN 1-0 (USB), at the rest frequency of each line.

Calibration data -Valid for 2007.12-2008.5

Calibration data for this season (2007.12-2008.5) are available here. We will supply calibration data for some spectral lines; CO 1-0 (USB), ¹³CO 1-0 (LSB), C¹⁸O 1-0 (LSB), H¹³CO⁺ 1-0 (LSB), etc. at the rest frequency of each line.

Calibration data for the past seasons (-2007.5)

Calibration data for the past seasons (2000.5-2007.5) are here.