A generalization of the double ramification cycle via log-geometry

Understand

We give a log-geometric description of the space of twisted canonical divisors constructed by Farkas--Pandharipande.

• In particular, we introduce the notion of a principal rubber $k$-log-canonical divisor, and we study its moduli space.
• It is a proper Deligne--Mumford stack admitting a perfect obstruction theory whose virtual fundamental cycle is of dimension $2g-3+n$.
• In the so-called strictly meromorphic case with $k=1$, the moduli space is of the expected dimension and the push-forward of its virtual fundamental cycle to the moduli space of stable curves equals the weighted fundamental class of the moduli space of twisted canonical divisors.