Abstract
The intensity mapping of Lyα emission during the epoch of
reionization will be contaminated by foreground emission lines from
lower redshifts. We calculate the mean intensity and the power spectrum
of Lyα emission at z ~ 7 and estimate the uncertainties according
to the relevant astrophysical processes. We find that the low-redshift
emission lines from 6563 Å Hα, 5007 Å [O III], and
3727 Å [O II] will be strong contaminants on the observed
Lyα power spectrum. We make use of both the star formation rate
and luminosity functions to estimate the mean intensity and power
spectra of the three foreground lines at z ~ 0.5 for Hα, z ~ 0.9
for [O III], and z ~ 1.6 for [O II], as they will contaminate the
Lyα emission at z ~ 7. The [O II] line is found to be the
strongest. We analyze the masking of the bright survey pixels with a
foreground line above some line intensity threshold as a way to reduce
the contamination in an intensity mapping survey. We find that the
foreground contamination can be neglected if we remove pixels with
fluxes above 1.4 × 10-20 W m-2.
| Original language | English |
|---|---|
| Pages (from-to) | 72-82 |
| Number of pages | 11 |
| Journal | The Astrophysical Journal |
| Volume | 785 |
| DOIs | |
| Publication status | Published - Apr-2014 |
Keywords
- cosmology: theory
- diffuse radiation
- intergalactic medium
- large-scale structure of universe