For the first individual exposure, Gaussian centers of the spectro- astrometric signal as a function of the velocity in both the W-E (east for ΔX > 0) and S-N (north for ΔY > 0) directions, in top and middle panels, respectively. Bottom panel shows the differential FWHM. The Hα line profile is overplotted in blue showing a clear P Cygni profile [ GIF ]
V. Agra-Amboage and P. J. V. Garcia, 2014, "Spectro-astrometry of V1515 Cygni", A&A, 565, A92. Paper.