Filip Gawron
Let $f\in S_k(\Gamma_0(N),\chi)^\text{new}$ be a newform of level $N$ and nebentypus $\chi$. Knowing $N$ and $\chi$, what can we say about the field $\mathbb{Q}_f$ generated by the Fourier coefficients of $f$? In particular,
What can we say about primes ramifying in $\mathbb{Q}_f$?
In the talk, I will show some numerical calculations in the case $k=2$ and trivial nebentypus. I will also discuss some existing results. Finally, I will comment on my recent work about ramification occurring when the level $N$ is non-optimal.