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Volume 556, August 2013
Article Number A66
Number of page(s) 18
Section Extragalactic astronomy
Published online 30 July 2013

Online material

Appendix A: Visibility fits

To derive source sizes for the observed emission, a simple model of a point source and a circular Gaussian was fit to the circle-averaged visibilities. These were derived by an azimuthal average around the u − v plane center with the UV_CIRCLE routine of the MAPPING software. Averaged visibilities are plotted in Fig. A.1. On the x-axis we show the distance from the u − v center in meters. The fitted parameters for the point source and Gaussian components are labeled PS and RS, respectively.

thumbnail Fig. A.1

Circle-averaged visibility fits. The best-fit parameters are labeled PS for the point source component and RS for the resolved component. The FWHM of the resolved component is given in arcseconds. For HNC and the continuum at 1 mm, the averaged visibilities are compared with models of different source size, which are labeled as (1)...(3).

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© ESO, 2013

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