  It was previously shown by Grunewald and Lubotzky that the automorphism group
of a free group, $\text{Aut}(F_n)$, has a large collection of virtual
arithmetic quotients. Analogous results were proved for the mapping class group
by Looijenga and by Grunewald, Larsen, Lubotzky, and Malestein. In this paper,
we prove analogous results for the automorphism group of a right-angled Artin
group for a large collection of defining graphs. As a corollary of our methods
we produce new virtual arithmetic quotients of $\text{Aut}(F_n)$ for $n \geq 4$
where $k$th powers of all transvections act trivially for some fixed $k$. Thus,
for some values of $k$, we deduce that the quotient of $\text{Aut}(F_n)$ by the
subgroup generated by $k$th powers of transvections contains nonabelian free
groups. This expands on results of Malestein and Putman and of Bridson and
Vogtmann.
