  The next Galactic supernova is expected to bring great opportunities for the
direct detection of gravitational waves (GW), full flavor neutrinos, and
multi-wavelength photons. To maximize the science return from such a rare
event, it is essential to have established classes of possible situations and
preparations for appropriate observations. To this end, we use a long-term
numerical simulation of the core-collapse supernova (CCSN) of a 17 solar-mass
red supergiant progenitor to self-consistently model the multi-messenger
signals expected in GW, neutrino, and electromagnetic messengers. This
supernova model takes into account the formation and evolution of a
protoneutron star, neutrino-matter interaction, and neutrino transport, all
within a two-dimensional shock hydrodynamics simulation. With this, we
separately discuss three situations: (i) a CCSN at the Galactic Center, (ii) an
extremely nearby CCSN within hundreds of parsecs, and (iii) a CCSN in nearby
galaxies within several Mpc. These distance regimes necessitate different
strategies for synergistic observations. In a Galactic CCSN, neutrinos provide
strategic timing and pointing information. We explore how these in turn deliver
an improvement in the sensitivity of GW analyses and help to guarantee
observations of early electromagnetic signals. To facilitate the detection of
multi-messenger signals of CCSNe in extremely nearby and extragalactic
distances, we compile a list of nearby red supergiant candidates and a list of
nearby galaxies with their expected CCSN rates. By exploring the sequential
multi-messenger signals of a nearby CCSN, we discuss preparations for
maximizing successful studies of such an unprecedented stirring event.

High Energy Astrophysical Phenomena;General Relativity and Quantum Cosmology;High Energy Physics - Experiment;Instrumentation and Detectors