Simons Observatory (SO) key targets are: the physics of primordial perturbations, identifying the correct model of an early inflationary epoch of the Universe; effective number of relativistic species; the sum of neutrino masses; observable deviations from the cosmological constant paradigm; galaxy evolution; redshift and duration of the reionization epoch. Simons Observatory key science targets are summarized in Table (1).
The 1σ forecast uncertainties on each parameter for the baseline and goal noise levels are specified. For the baseline case, we show the forecast uncertainty, and also, for each case, we inflate the uncertainty by 25% (rounding up to 1 significant figure) as a proxy for additional systematic errors, to be refined in future studies. For each science target we also give the current uncertainty to ease the comparison with expected SO performance.
The Simons Observatory has a set of secondary science goals summarized in Table (2). These include measuring additional non-Gaussian parameters describing the primordial perturbations and again identifying the correct model of an early inflationary epoch of the Universe, probing Big Bang Nucleosynthesis by measuring the primordial helium fraction, constraining interactions between dark matter particles and baryons, constraining the mass of ultra-light-axion dark matter, measuring the dark energy equation of state to cross-check constraints from optical surveys, calibrating the shear bias for LSST, and constraining the ionization efficiency in models of reionization.
The Simons Observatory is poised to advance a broad range of Galactic science. The high angular resolution maps of polarized emission from SO will enable characterization of interstellar turbulence on small spatial scales and the mapping of the structure of the magnetic field over a range of scales and environments, from diffuse regions to cold cores. With the multi-frequency SO data, we will characterize the physics of Galactic emission by improving constraints on the dust and synchrotron spectral energy distributions, including the presence of multiple dust populations, curvature in the synchrotron spectrum, and the existence of polarized anomalous microwave emission.
Finally, SO’s broader aim is to produce several high-level legacy catalogues for use by the general astronomical community. The extent of these catalogues is summarized in the first entry of Table (2).