next previous
Up: Monitoring MWC560 V 694

2. Observations

The spectra were obtained in the coudé-spectrograph of the 2-m telescope at Rozhen Observatory (Bulgaria) with typical exposure times of 2-3 hours. Hydrogen treated, 103aO emulsion was used. Each plate covered a spectral interval from 3600Å to 4950Å and had a spectral resolution of about 0.35Å. Iron-argon hollow cathode lamp spectrum was obtained for wavelength calibration and the photometric calibration was achieved by 10-steps sensitometer exposures on each plate. The typical S/N ratio on the local continuum level was 10-15.

The spectra were digitized by MDM6 Joyce Loebl microdensitometer, with 20tex2html_wrap_inline1025 wide slit and 10tex2html_wrap_inline1027 step. We used the software system ReWiA (Borkowski 1988) to process the data. The spectra were linearized using dispersion curves of not less than tex2html_wrap_inline1029 0.05Å\ accuracy.

Figure 1: The evolution of tex2html_wrap_inline1031 over the whole period of observation. Each observing season is shown in a separate panel. In the upper part of the rightmost panel an additional picture is inserted to define the different types of Balmer absorption components - SSBA (strong shifted Balmer absorptions) and SBA (slowest Balmer absorptions)

All the spectra shown in Figs. 1 (click here), 2 (click here) and 3 (click here) are normalized to the local continuum level and shifted for plot clarity.

In Tables 1 and 3 and Figs. 4 (click here) and 5 (click here) single measurements of equivalent widths and peak intensities of some spectral features are presented. The accuracy of these measurements depends on two reasons mainly: i) the typical errors associated with the photographic emulsion which can be up to tex2html_wrap_inline1033 tex2html_wrap_inline1035 and ii) the difficulties arisen during the continuum level fitting procedure. We can assume a value of about 20% as an upper limit for the errors in these single measurements.

Figure 2: The spectral region around tex2html_wrap_inline1037, CaIIK and tex2html_wrap_inline1041 in the spectrum of MWC560. Each observing season is represented by two spectra. The horizontal and vertical marks show the different absorption lines and their components. The negative numbers on the right side represent the radial velocity of the absorptions with the highest shifts in each spectrum

next previous
Up: Monitoring MWC560 V 694

Copyright by the European Southern Observatory (ESO)