  Although low-mass star-forming galaxies are the leading candidates of the
reionisation process, we cannot conclusively rule out high-mass star-forming
galaxies as candidates. While most simulations indicate the former is the best
candidate some models suggest that at z > 6 massive, UV-bright galaxies -
"oligarchs" - account for at least 80% of the ionising budget. To test this
hypothesis we target massive (log10 (M*[Msol]) > 10), UV-bright (MUV ~ -22) Lya
emitters at z > 7 in archival data, observed with similar resolution
spectrographs (VLT/X-shooter and Keck/MOSFIRE). To increase the reliability of
our conclusions we stack all spectra and obtain a deep-stacked spectrum of
24.75 hrs. The stacked Lya profile displays a clear asymmetric red peak and an
absence of a blue peak. We additionally estimate the intrinsic stacked Lya
profile of our targets by correcting for IGM transmission using a range of
neutral hydrogen fractions, finding no significant change in the profile. We
measure a velocity offset Vred > 300 km/s and an asymmetry in our red peak A
~3. Using various models and estimators such as the peak separation, the
asymmetry of the red peak, the ratio between Lya and Hb and the beta slope, we
conclude that the escape fraction in these three UV bright, massive (10^10
Msol), z > 7 galaxies is fesc(LyC) < 10%.
