Southern spectrophotometric standards, 2

Abstract

We have obtained new observations of both secondary and tertiary spectrophotometric standards with the RC spectrographs and CCD cameras on the 1.5-m and 4-m telescopes at CTIO in the wavelength range 6000-10500 A. We use the secondary spectrophotometric standards in order to calculate new fluxes for the tertiary standards of Stone and Baldwin (1983), as well as for three stars of the northern hemisphere from Stone (1977). We find that the synthetic magnitudes calculated from our spectra through the I KC band agree extremely well the observed photometry, to better than 1% on average. For the monochromatic fluxes, we find an internal precision better than 0.01 mag blueward of 9000 A, and increasingly larger for longer wavelengths. We present also a fine grid of averaged monochromatic fluxes (at continuous steps of 16 A) for the ten secondary standards selected for our program, to be used in the flux calibration of high dispersion spectra. Finally, we provide combined fluxes for all secondary and tertiary standards in the range 3300-10500 A resulting from the calibration presented here with the one published in Paper I (Hamuy et al. 1992).