SIGNALS: I. Survey Description
  SIGNALS, the Star formation, Ionized Gas, and Nebular Abundances Legacy
Survey, is a large observing program designed to investigate massive star
formation and HII regions in a sample of local extended galaxies. The program
will use the imaging Fourier transform spectrograph SITELLE at the
Canada-France-Hawaii Telescope. Over 355 hours (54.7 nights) have been
allocated beginning in fall 2018 for eight consecutive semesters. Once
completed, SIGNALS will provide a statistically reliable laboratory to
investigate massive star formation, including over 50 000 resolved HII regions
: the largest, most complete, and homogeneous database of spectroscopically and
spatially resolved extragalactic HII regions ever assembled. For each field
observed, three datacubes covering the spectral bands of the filters SN1 (363
-386 nm), SN2 (482 - 513 nm), and SN3 (647 - 685 nm) are gathered. The spectral
resolution selected for each spectral band is 1000, 1000, and 5000,
respectively. As defined, the project sample will facilitate the study of
small-scale nebular physics and many other phenomena linked to star formation
at a mean spatial resolution of 20 pc. This survey also has considerable legacy
value for additional topics including planetary nebulae, diffuse ionized gas,
andsupernova remnants. The purpose of this paper is to present a general
outlook of the survey, notably the observing strategy, galaxy sample, and
science requirements.
