Trying to find an answer to this question, I came across many sources that are in complete in contradiction. For example Wikipedia states that a typical quasar has a power of $10^{40}$ watts while according to this, the most powerful quasar has a power of $10^{39}$ watts ($10^{46}$ ergs). So now which is correct, and what is the correct number for a typical quasar ?


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It is difficult to keep track on these things, specially since quasars are also highly variable. Trying to answer the question of the post title, I found this example that sound pretty impressive: $7\times 10^{14}\,{\rm L_\odot}$, or $1.4\times 10^{41}$ W.

The ESO press release refers to the kinetic luminosity, or the kinetic energy of the outflow per unit time, not quasar radiative luminosity.

According to this paper based on SDSS data, just to give an example, the first thing is that the mean luminosity of the quasar population changes with time, from high to low redshift. But apparently, the quasar population distributes broadly around absolute magnitude $-26$, which is interesting since this is close to the apparent magnitude of the Sun. So a good rule of thumb might be that a quasar at 10 parsecs from Earth would look as bright as the Sun, or would have a luminosity of $\sim4\times 10^{36}$ W. These are very rough numbers.


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