SDSS-IV MaNGA IFS GALAXY SURVEY-SURVEY DESIGN, EXECUTION, AND INITIAL DATA QUALITY

Abstract

The MaNGA Survey (Mapping Nearby Galaxies at Apache Point Observatory) is one of three core programs in the Sloan Digital Sky Survey IV. It is obtaining integral field spectroscopy for 10,000. nearby galaxies at a spectral resolution of R similar to 2000 from 3622 to 10354 angstrom. The design of the survey is driven by a set of science requirements on the precision of estimates of the following properties: star formation rate surface density, gas metallicity, gravitational mass as a function of radius. We describe how these science requirements set the depth of the observations and dictate sample selection. The majority of targeted galaxies are selected to ensure uniform spatial coverage in units of effective radius (R-e) while maximizing spatial resolution. About two-thirds of the sample is covered out to 1.5R(e) (Primary sample), and one-third. of the sample is covered to 2.5R(e) (Secondary sample). We describe the survey execution with details that would be useful in the design of similar future surveys. We also present statistics on the achieved data quality, specifically. the point-spread function, sampling uniformity, spectral resolution, sky subtraction, and flux calibration. For our Primary sample, the median r-band signal-to-noise ratio is similar to 70 per 1.4 angstrom pixel for spectra stacked between 1R(e) and 1.5R(e). Measurements of various galaxy properties from the first-year data show that we are meeting or exceeding the defined requirements for the majority of our science goals.