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All the parameters provided in this database have been obtained using the the MIRIAD (Sault et al. 1995) task MBSPECT. MBSPECT makes a spectrum of the velocity (or frequency) axis of a cube. The spectrum is beam-weighted, over the width specified, for the other image axes. Robust spectral baselines of order one are fitted, and the profile parameterised (velocities, widths, moments). All the parameters are obtained for cubes hanning smoothed to a resolution of 10 km/s. For each source the input parameter list and the output provided by MIRIAD are given in the ASCII file version of the final spectrum. Tipically, for unresolved sources (the great majorirty of the sources detected by AGES) we use the following parameters: width=5,5 (i.e. 5'x5') being the spatial width of the box in pixels (in RA and DEC) within which the spectrum is integrated. xaxis=FELO: the x-axis is plotted as 'optical' velocity'. yaxis=point: the pixels enclosed in the x-y area specified are optimally weighted according to the beam parameters, assuming that the source is unresolved. xrange=V-1000,V+1000: velocity range plotted in the spectrum and used to determine the bandpass (V is the galaxy's reccessional velocity). hann=1: no additional smoothing. order=1: order of optional robust (clipped polynomial) fit (0-10) to be applied to the spectral axis. The fit is always subtracted from any output data written. profile= the velocity range over which the HI profile fit is performed, and the parameters estimated. options=posfit,measure. Posfit: a source position is estimated from a Gaussian fit to the moment map. The moment map is formed using the velocity range specified by the profile parameter. This new position is used when forming the spectrum. Measure various spectral parameters on plotted spectrum. Robust parameters are calculated by using an algorithm which minimises the mean absolute deviation of the flux-weighted velocities. mask=This specifies the x-axis ranges to be excluded from any continuum fit. We usually exclude the region in which the profile is computed and any RFI or strong feature present in the spectrum. Object ID |