  Extensions of the Standard Model (SM) with sterile neutrinos are well
motivated from the observed oscillations of the light neutrinos and they have
shown to successfully explain the Baryon Asymmetry of the Universe (BAU)
through, for instance, the so-called ARS leptogenesis. Sterile neutrinos can be
added in minimal ways to the SM, but many theories exist where sterile
neutrinos are not the only new fields. Such theories often include scalar
bosons, which brings about the possibility of further interactions between the
sterile neutrinos and the SM. In this paper we consider an extension of the SM
with two sterile neutrinos and one scalar singlet particle and investigate the
effect that an additional, thermalised, scalar has on the ARS leptogenesis
mechanism. We show that in general the created asymmetry is reduced due to
additional sterile neutrino production from scalar decays. When sterile
neutrinos and scalars are discovered in the laboratory, our results will
provide information on the applicability of the ARS leptogenesis mechanism.
