There is an official version available online, as well as a preprint version: arXiv:1407.2654 [math.AG].

We produce new explicit examples of genus-2 curves over the rational numbers
whose Jacobian varieties have rational torsion points of large order. In
particular, we produce a family of genus-2 curves over **Q** whose Jacobians
have a rational point of order 48, parametrized by a rank-2 elliptic curve
over **Q**, and we exhibit a single genus-2 curve over **Q** whose Jacobian
has a rational point of order 70, the largest order known. We also give
new examples of genus-2 Jacobians with points of order 27, 28, 36, and 39.

Most of our examples are produced by ‘gluing’ two elliptic curves together along their
*n*-torsion subgroups, where *n* is either 2 or 3. The 2-gluing examples
arise from techniques developed by the author in joint work with Leprévost
and Poonen 15 years ago. The 3-gluing examples are made possible by an
algorithm for explicit 3-gluing over non-algebraically closed fields recently
developed by the author in joint work with Bröker, Lauter, and Stevenhagen.

The curve with a torsion point of order 70 can be written