Computations in radiofrequency spectroscopy
Abstract
The paper concentrates on some data acquisition and data reduction techniques and some problems of data interpretation in spectralline radio astronomy, without going into specific data on particular atoms or molecules or into theoretical interpretations. A mathematical definition of the power spectrum is developed, and the principles are set forth for power spectrum estimation using scanning filters, multichannel filter systems, acoustooptic (Braggcell) spectrometers, autocorrelation spectrometers, the maximum entropy method, and direct Fourier transform methods. Properties of some radio sources, feature widths and spectral coverage are examined in order to establish approximate numbers for the resolutions and bandwidths needed in a spectrometer for radio astronomy. The main calibration problem, involving conversion of the apparent fluxdensity scale to an apparent brightness temperature scale, is examined. The problem of instrumental baseline curvature is discussed along with mathematical techniques for fitting Gaussians and baselines.
 Publication:

Methods in Computational Physics. Volume 14  Radio astronomy
 Pub Date:
 1975
 Bibcode:
 1975mcpr...14..177B
 Keywords:

 Astronomical Spectroscopy;
 Data Acquisition;
 Data Reduction;
 Power Spectra;
 Radio Spectroscopy;
 Bandwidth;
 Bragg Cells;
 Brightness Temperature;
 Calibrating;
 Interpretation;
 Radio Astronomy;
 Astronomy