  Studying gamma-ray emission by Galactic objects is key to understanding the
origins and acceleration mechanisms of Galactic cosmic ray electrons and
hadrons. The HAWC observatory provides an unprecedented view of the gamma-ray
sky at TeV energies and is particularly suited for the study of Galactic
objects. However, the interpretation of the measured data poses several
challenges. The high density of sources and source candidates can cause source
confusion and make it harder to disentangle the origin of the emission. The
relatively low angular resolution of HAWC, compared to instruments in optical
or radio wavelengths, can further cause the emission of neighboring sources to
bleed into each other or even make them look like one extended source. On the
other hand, with its wide field of view, HAWC is uniquely suited for the study
of extended sources. However, this requires the simultaneous modeling of both
their morphology and emission spectrum. Joint likelihood fits to data taken
over a larger range of energies can help overcome these challenges and achieve
the full potential of the HAWC detector. In this presentation, we will discuss
how systematic uncertainties related to joint likelihood fits can affect the
measurements.
