  The MicroBooNE liquid argon time projection chamber (LArTPC) has been taking
data at Fermilab since 2015 collecting, in addition to neutrino beam,
cosmic-ray muons. Results are presented on the reconstruction of Michel
electrons produced by the decay at rest of cosmic-ray muons. Michel electrons
are abundantly produced in the TPC, and given their well known energy spectrum
can be used to study MicroBooNE's detector response to low-energy electrons
(electrons with energies up to ~50 MeV). We describe the fully-automated
algorithm developed to reconstruct Michel electrons, with which a sample of
~14,000 Michel electron candidates is obtained. Most of this article is
dedicated to studying the impact of radiative photons produced by Michel
electrons on the accuracy and resolution of their energy measurement. In this
energy range, ionization and bremsstrahlung photon production contribute
similarly to electron energy loss in argon, leading to a complex electron
topology in the TPC. By profiling the performance of the reconstruction
algorithm on simulation we show that the ability to identify and include energy
deposited by radiative photons leads to a significant improvement in the energy
measurement of low-energy electrons. The fractional energy resolution we
measure improves from over 30% to ~20% when we attempt to include radiative
photons in the reconstruction. These studies are relevant to a large number of
analyses which aim to study neutrinos by measuring electrons produced by
$\nu_e$ interactions over a broad energy range.
