  Lorentz invariance (LI) has a central role in science and its violation (LIV)
at some high-energy scale has been related to possible solutions for several of
the most intriguing puzzles in nature such as dark matter, dark energy, cosmic
rays generation in extreme astrophysical objects and quantum gravity. We report
on a search for LIV signal based on the propagation of gamma rays from
astrophysical sources to Earth. An innovative data analysis is presented which
allowed us to extract unprecedented information from the most updated data set
composed of 111 energy spectra of 38 different sources measured by current
gamma-ray observatories. No LIV signal was found, and we show that the data are
best described by LI assumption. We derived limits for the LIV energy scale at
least 3 times better than the ones currently available in the literature for
subluminal signatures of LIV in high-energy gamma rays.
