Cosmological constraints from line intensity mapping with interlopers
  Understanding the formation and evolution of the Universe is crucial for
cosmological studies, and the line intensity mapping provides a powerful tool
for this kind of study. We propose to make use of multipole moments of
redshift-space line intensity power spectrum to constrain the cosmological and
astrophysical parameters, such as the equation of state of dark energy, massive
neutrinos, primordial non-Gaussianity, and star formation rate density. As an
example, we generate mock data of multipole power spectra for H-alpha 6563AA,
[OIII] 5007AA and [OII] 3727AA measured by SPHEREx experiment at z=1
considering contaminations from interloper lines, and use Markov Chain Monte
Carlo (MCMC) method to constrain the parameters in the model. We find a good
fitting result of the parameters compared to their fiducial values, which means
that the multipole power spectrum can effectively distinguish signal and
interloper lines, and break the degeneracies between parameters, such as line
mean intensity and bias. We also explore the cross power spectrum with CSST
(Chinese Space Station Telescope) spectroscopic galaxy survey in the
constraints. Since more accurate fitting results can be obtained by including
measurements of the emission lines at higher redshifts out to z=3 at least and
cross-correlations between emission lines can be involved, the line intensity
mapping is expected to offer excellent results in future cosmological and
astrophysical studies.
