A Spitzer Space Telescope survey of extreme Asymptotic Giant Branch
  stars in M32
  We investigate the population of cool, evolved stars in the Local Group dwarf
elliptical galaxy M32, using Infrared Array Camera observations from the
Spitzer Space Telescope. We construct deep mid-infrared colour-magnitude
diagrams for the resolved stellar populations within 3.5 arcmin of M32's
centre, and identify those stars that exhibit infrared excess. Our data is
dominated by a population of luminous, dust-producing stars on the asymptotic
giant branch (AGB) and extend to approximately 3 mag below the AGB tip. We
detect for the first time a sizeable population of `extreme' AGB stars, highly
enshrouded by circumstellar dust and likely completely obscured at optical
wavelengths. The total dust-injection rate from the extreme AGB candidates is
measured to be $7.5 \times 10^{-7}$ ${\rm M}_{\odot} \, {\rm yr}^{-1}$,
corresponding to a gas mass-loss rate of $1.5 \times 10^{-4}$ ${\rm M}_{\odot}
\, {\rm yr}^{-1}$. These extreme stars may be indicative of an extended
star-formation epoch between 0.2 and 5 Gyr ago.
