  There are only a few ways to constrain the Era of Reionization and the
properties of high redshift (z>6) stars through observations. Here, we discuss
one of these observables - the spectrum of the Near Infrared Background - and
how it is potentially affected by the transition from Population III to
Population II stars. The stronger Lyman-alpha emission expected from massive
Population III stars could result in a 'bump' in the spectrum of the Near
Infrared Background (referred to in this work as the Lyman-alpha bump). The
strength and shape of this bump can reveal properties of Population III stars.
The Lyman-alpha bump is predicted to be higher if Population III stars are more
massive and present at lower redshifts. The shape of the bump is governed by
the star formation rate and the time it takes Population III stars to
transition to Population II stars. If Population III stars are indeed massive,
a bump is predicted as long as Population III stars exist at z < 15, even if
their star formation rate is as low as 10^-7 M_sun yr^-1 Mpc^-3. This means
that there may be some observational signature in the Near Infrared Background
of small pockets of metal-free gas forming Population III stars at z ~ 6, even
if they are quite rare.
