  We use the ROSAT public data archive to study the X-ray emission of a sample
of supposedly single A0-F6 spectral type stars from the Bright Star Catalogue.
We detected X-ray emission from 19 A and 33 F-type stars. However, our results
are not sufficient to associate with certainty the X-ray emission to the A-type
stars themselves, since the usual argument that it may originate from a binary
companion can not be excluded. A spectral analysis was conducted for 14 sources
(3 A and 11 F), finding that for 12 of them a two temperature thermal plasma
model is needed to reproduce the observed spectra. The two temperatures are
centered at 0.13 and 0.54 keV, respectively. The values found for the higher
temperature are lower than that ones of X-ray selected single late-type stars.
The X-ray luminosities are in the range 1E28 < L_X < 1E30 erg/s, with a
distribution similar to that of active late-type stars. No correlation is found
between L_X and B-V color, Vsin(i) and L_bol, while a positive correlation is
found between the X-ray luminosity and the hardness ratio.

Astrophysics