The BINGO Project VII: Cosmological Forecasts from 21cm Intensity
  Mapping
  The 21cm line of neutral hydrogen (HI) opens a new avenue in our exploration
of the structure and evolution of the Universe. It provides complementary data
to the current large-scale structure observations with different systematics,
and thus it will be used to improve our understanding of the $\Lambda$CDM
model. Among several radio cosmological surveys designed to measure this line,
BINGO is a single-dish telescope mainly designed to detect baryon acoustic
oscillations (BAOs) at low redshifts ($0.127< z<0.449$). Our goal is to assess
the fiducial BINGO setup and its capabilities of constraining the cosmological
parameters, and to analyze the effect of different instrument configurations.
We used the Phase 1 fiducial configuration of the BINGO telescope to perform
our cosmological forecasts. In addition, we investigated the impact of several
instrumental setups, taking into account some instrumental systematics, and
different cosmological models. Combining BINGO with Planck temperature and
polarization data, the projected constraint improves from a $13\%$ and $25\%$
precision measurement at the $68\%$ confidence level with Planck only to $1\%$
and $3\%$ for the Hubble constant and the dark energy equation of state (EoS),
respectively, within the wCDM model. Assuming a Chevallier-Polarski-Linder
parameterization, the EoS parameters have standard deviations given by
$\sigma_{w_0} = 0.30$ and $\sigma_{w_a} = 1.2$, which are improvements on the
order of $30\%$ with respect to Planck alone. Also, we can access information
about the HI density and bias, obtaining $\sim 8.5\%$ and $\sim 6\%$ precision,
respectively, assuming they vary with redshift at three independent bins. The
fiducial BINGO configuration will be able to extract significant cosmological
information from the HI distribution and provide constraints competitive with
current and future cosmological surveys. (Abridged)
