The Role of Observers in the Early Universe

The next possibility then is that, again, what we're measuring is the total amount of stellar mass. And so that requires some underlying models to go from the light to the stellar mass. If this is not quite done correctly, if one assumes a certain stellar initial mass function, and it's really a different one in this galaxy, that could lead to some discrepancy. The other issue we touched on is whether there are substantial contributions from accreting black holes in these early galaxies.