3.1.26. Rbin: optimal rebinning of the data and response, including saving

3.1.26.1. Overview

This command rebins (a part of) the data (thus both the spectrum and the response) to the optimal bin size given the statistics of the source as well as the instrumental resolution. This is recommended to do in all cases, in order to avoid oversampling of the data. The theory and algorithms used for this rebinning are described in detail in Optimal definition of respons matrices.

It does essentially the same as the obin command as far as binning of the data channels is concerned, but in addition it also optimally bins the model energy grid. All prescriptions for this are given in the paper of Kaastra and Bleeker (2016). In addition, it stores the newly binned spectrum and response, with a different name, in the same directory where the original data are. If the original data rea named data.spo and data.res, the new names will be databin0.spo and databin0.res.

It is highly recommended to apply the binning to the full data set, and to do one instrument at a time, to reduce the use of memory, especially in cases with very large matrices. In those cases, the compression may take several minutes.

Further, it is best practice to quit spex after the creation of the reduced dataset, and to load the reduced data in a new session. If you want to see the difference, you can load the original and the binned data as two separate instruments in spex, apply a simple model and see the differences in a plot.

3.1.26.2. Syntax

The following syntax rules apply:

rbin #i1: : Simplest command allowed. #i1: is the range in data channels over which the binning needs to take place.

rbin #r1: #i: unit #a : The same command as above, except that now the ranges over which the data is to be binned (#r1:) are specified in units (#a) different from data channels. These units can be eV, keV, Å, as well as in units of Rydberg (ryd), Joules (j), Hertz (hz) and nanometers (nm).

rbin [instrument #i1:] [region #i2:] #i3: : Here #i3: is the same as #i1: in the first command. However, here one can specify the instrument range #i1: and the region range #i2: as well, so that the binning is done only for one given data set.

rbin [instrument #i1:] [region #i2:] #r1: [unit #a] : This command is the same as the above, except that here one can specify the range over which the binning should occur in the units specified by #a. These units can be eV, Å, keV, as well as in units of Rydberg (ryd), Joules (j), Hertz (hz) and nanometers (nm).

3.1.26.3. Examples

rbin 1:10000 : Optimally bins the data channels 1:10000.