Template bank for spinning compact binary mergers in the second observation run of Advanced LIGO and the first observation run of Advanced Virgo

We describe the methods used to construct the aligned-spin template bank of gravitational waveforms used by the Gstreamer and Ligo Algorithm Library (GstLAL)-based pipeline to analyze data from the second observing run of Advanced Laser Interferometer Gravitational Wave Observatory (LIGO) and the first observing run of Advanced Virgo. The bank expands upon the parameter space covered during Advanced LIGO's first observing run, including coverage for merging compact binary systems with total mass between 2 M and 400 M and mass ratios between 1 and 97.988. Thus the systems targeted include merging neutron star-neutron star systems, neutron star-black hole binaries, and black hole-black hole binaries expanding into the intermediate-mass range. Component masses less than 2 M have allowed (anti-)aligned spins between ±0.05, while component masses greater than 2 M have allowed (anti-)aligned between ±0.999. The bank placement technique combines a stochastic method with a new grid-bank method to better isolate noisy templates, resulting in a total of 677,000 templates.