Rotational velocities of A-type stars -: II.: Measurement of v sin i in the northern hemisphere

This work is the second part of the set of measurements of v sin i for A-type stars, begun by Royer et al. (2002). Spectra of 249 B8 to F2-type stars brighter than V = 7 have been collected at Observatoire de Haute-Provence (OHP). Fourier transforms of several line profiles in the range 4200-4600 Angstrom are used to derive v sin i from the frequency of the first zero. Statistical analysis of the sample indicates that measurement error mainly depends on v sin i and this relative error of the rotational velocity is found to be about 5% on average. The systematic shift with respect to standard values from Slettebak et al. (1975), previously found in the first paper, is here confirmed. Comparisons with data from the literature agree with our findings: v sin i values from Slettebak et al. are underestimated and the relation between both scales follows a linear law v sin i(new) = 1.03 v sin i(old) + 7.7. Finally, these data are combined with those from the previous paper (Royer et al. 2002), together with the catalogue of Abt & Morrell (1995). The resulting sample includes some 2150 stars with homogenized rotational velocities.