In this work we present the first of two papers devoted to the study of the
X-ray spectral characteristics of Seyfert 1 galaxies in the Piccinotti sample.
In particular we analyse here the BeppoSAX broad band (0.1-100 keV) data of 4
objects which, despite their X-ray brightness, have been historically poorly
studied due to their late identification with an AGN; these are H0111-149
(MKN1152), H0235-525 (ESO198-G24), H0557-385 (IRAS F05563-3820) and H1846-786
(IRAS F18389-7834). We have assumed for all the sources a baseline model which
includes a power law with an exponential cut-off plus a reflection component
and an iron K_alpha line; we have also searched for the presence of intrinsic
absorption and/or a soft excess component. Our analysis indicates the presence
of complex absorption in two objects (H0557-385 and H0111-149) best described
by a combination of two uniform absorbers, one cold and one warm. Only in one
source, H0557-385, a soft excess component has been measured. The primary
continuum is best described by a canonical power law (Gamma=1.7-2) with a high
energy cut-off in the range 40-130 keV. A cold reflection component is likely
present in all sources with values ranging from less than 0.6 to higher than 2.
In 3 out of 4 objects we find a cold iron line having equivalent width typical
of Seyfert 1s (100-200 eV).Comment: 6 pages, 2 figures, accepted for publication as a Research Note in
Astronomy and Astrophysic
