## The modular curve $X_{515}$

Curve name $X_{515}$
Index $96$
Level $16$
Genus $2$
Does the subgroup contain $-I$? Yes
Generating matrices $\left[ \begin{matrix} 7 & 7 \\ 0 & 7 \end{matrix}\right], \left[ \begin{matrix} 7 & 0 \\ 0 & 15 \end{matrix}\right], \left[ \begin{matrix} 1 & 0 \\ 0 & 7 \end{matrix}\right], \left[ \begin{matrix} 5 & 0 \\ 0 & 1 \end{matrix}\right]$
Images in lower levels
 Level Index of image Corresponding curve $2$ $3$ $X_{6}$ $4$ $6$ $X_{13}$ $8$ $24$ $X_{102}$
Meaning/Special name
Chosen covering $X_{235}$
Curves that $X_{515}$ minimally covers $X_{235}$
Curves that minimally cover $X_{515}$
Curves that minimally cover $X_{515}$ and have infinitely many rational points.
Model $y^2 = x^5 - 2x^4 - 2x^2 - x$
Info about rational points
 Rational point Image on the $j$-line $(1 : 0 : 0)$ $\infty$ $(0 : 0 : 1)$ $\infty$
Comments on finding rational points The rank of the Jacobian is 0. We use the method of Chabauty.
Elliptic curve whose $2$-adic image is the subgroup None
Generic density of odd order reductions N/A