  One of the major challenges in particle physics and cosmology is
understanding why there is an asymmetry between matter and antimatter in the
Universe. One possible explanation for this phenomenon is thermal leptogenesis,
which involves the addition of at least two right-handed neutrinos (RHNs) to
the standard model. Another possible explanation is baryogenesis through the
hypermagnetic fields which involves the ${\rm U}_Y(1)$ anomaly and helical
hypermagnetic fields in the early Universe. In this paper, after reviewing the
thermal leptogenesis and baryogenesis through the ${\rm U}_Y(1)$ anomaly, we
investigate the simplest model that combines these two scenarios and explore
the parameter space for optimal results. Our results show that the combined
scenario permits a specific region of parameter space that is not covered by
either one separately. In fact, the minimum required mass scale of the RHN and
strength of initial hypermagnetic helicity are reduced by one order of
magnitude in our model. Moreover, we find that in the combined scenario,
leptogenesis and baryogenesis through the ${\rm U}_Y(1)$ anomaly can either
amplify or reduce the effect of each other, i.e., the generated asymmetry,
depending on the sign of the helical hypermagnetic fields. Finally, we show the
surprising result that a drastic amplification can occur even when the initial
abundance of RHN is its equilibrium value for leptogenesis.
