![]() ![]() To produce the position velocity diagrams discussed in Sect. The 3 σ error in the wavelength calibration obtained is ~4 km s -1 ( σ = 1.2 km s -1). The calibrated final spectra were averaged for consecutive exposures in each setting and the continuum normalised.įurther data processing was performed for the R ~ 3000 spectra. The wavelength calibration was done by correlating to a HeAr lamp spectrum. Bias and flats were taken in a standard way. Spectrophotometric standard stars were taken from the list of Hamuy ( 1992, 1994) and observed with a wider 5.0″ slit. The slit orientation during the 2007 campaign was east-west, to cover only the C component (“Slit C only” in Fig. 1, to avoid a contamination by the neighbouring components as much as possible and to resolve the C source and the arc individually. Slit orientations were applied as shown in Fig. The spectra obtained in 2006 were taken with grism 11 and a 1.0″ slit, covering 3380–7520 Å at a dispersion of 2.04 Å/pix and a mean resolution R ~ 400. SpectroscopyĮFOSC2 spectra were obtained on March 1 and April 20, 2006, as well as on Augand August 12, 2008. In addition, we used SExtractor to extract the photometry and colour determination of all ~2000 sources in the EFOSC2 field (about 5.5′ × 5.5′), in order to check whether more objects belong to the HD 155448 system. Landolt standard fields (Landolt 1992) for zero points were observed just prior to the science data. The aperture photometry of source C does not include the arc-shaped emission region. Components A, B, and C have a flux error of 0.1 mag due to the problem in resolving their fluxes. The B2 source is not resolved from B1 in the optical filters. Despite the short exposures, the A component was saturated in the V and R filters. Eight frames of 1 s integration time were co-added for each filter. To better resolve the emission between the components, the data were re-sampled to 0.079′′/pix. These imaging data have a binning of 1 (i.e. 1984) at the 3.6 m telescope in La Silla. Photometryīroadband photometry in the B, V, and R filters was obtained on February 26, 2006 with EFOSC2 (Buzzoni et al. EFOSC2 optical imaging and spectroscopy A.2.1. There were problems both with the calibrator stars and with the camera’s ADU conversion factor during this night, and weather conditions were not very stable. No PSF subtraction was applied in this case.ĭespite the high sensitivity of the ADONIS data, no reliable photometry could be obtained. Figure 1 shows an ADONIS H band exposure. ![]() Data cube clean-up, dark and flatfield correction, as well as sky subtraction were performed in standard ways. The mask’s fixed position meant that no jitter offsets were possible. We co-added ten exposures of 60 s in both filters. For HD 155448, a mask of 1.4′′ and a lens scale with 0.1′′/pix were used. Details on the coronograph and its performance are given in Beuzit et al. ![]() We attached a fully opaque coronographic mask in front of the Lyot (pupil) stop to reject the peak of the PSF for the brightest source, to increase the integration time and sensitivity in order to reveal fainter structures. Our data were acquired on June 8, 2000 in the H and SK (short K) filter with total exposure times up to 600 s. ADONIS was coupled with the near-IR camera SHARPII+ which operates in the J to K band. Typical Strehl ratios were around 0.1 in J band and 0.3 in H band. 1997a) was available on the 3.6 m telescope at ESO La Silla until September 2002. The ESO ADaptive Optics Near Infrared System (ADONIS Beuzit et al. Online material Appendix A: Details on the observations and data reduction A.1.
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