Astronomy · Note

Notes on PdBI/IRAM data reduction – I. Get Data Ready

This is a personal note about PdBI/IRAM spectral data reduction. The steps will start from transferring the raw data to the local hard-drive, organising raw data, calibration with \tt{CLIC/GILDAS} to the further data reduction with \tt{MAPPING/GILDAS} procedure. The final stage will be mapping and acquire the spectra. If you have any questions or comments, please feeling free to contact me.

PART I: Get Data Ready (Get proj, etc.)

Now, let’s take a high-z observation project for example. Assuming we have observed a molecular line of a high-z galaxy in 2012. So our project name (starting from 2014, a new proposal system called PMS took over the old one, the project naming system has also been changed) would be:


W is 2012, V is for 2011 and X is for 2013, etc. I guess there’s a loop of the letters starts from a certain date; 0 is for the target index in this proposal, it could be WAB4, WBB4 and WCB4, …; B4 is the project index, 16th, hexadecimal.
And also we have an observation project name containing the data information, and it could be:


Just as the proposed project code X represents the year “2013”, C stands for December, the hexadecimal form of the month; 12: the date 12th.
Thus the raw data file of one observation will be like this:


for the source, WAB4 observed on Dec 12th, 2013. IPB file contains the data scan by scan, and OBS & RDI files store the observation parameters.

Now we need to download the data from IRAM data centre to the computers that we perform data reduction (usually at IRAM-HQ) by using:

getproj -p w0b4 -s wab4

The data (subproject wab4 from project w0b4) will be downloaded to the “~/tmp/DATA” directory (actually, it’s a link to the “/scratch/DATA” directory).
You will need to create several directories for data calibration. Usually, they will be generated automatically after getting the project, the calibration directory is under ~/calib, such as


And also there is a ~/reports directory containing some very useful notes from DoA for performing better calibration, and a ~/map for storing the results from your further data analysis.
After all, these get ready, you can now move on to the data calibration.