The gravitational-wave (GW) spectrum provides a new window for observations of the universe. A network of ground-based detectors including LIGO, Virgo, and GEO seeks to make the first direct detections of gravitational waves in at frequencies between tens and thousands of hertz. The Laser Interferometer Space Antenna (LISA), a planned joint mission of NASA and the European Space Agency (ESA), is expected to measure gravitational waves with frequencies from a fraction of a millihertz to tens of millihertz.
Long-lived nearly periodic signals are expected to be emitted in the LIGO band by rapidly-rotating deformed neutron stars and at LISA frequencies by binary systems of white dwarf stars. I will present work done to search for simulated white-dwarf binary signals in simulated LISA data as part of the Mock LISA Data Challenges, using
software originally developed for LIGO Scientific Collaboration analyses. I will also describe a cross-correlation method developed recently for ground-based periodic GW searches.