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Intensity mapping provides a unique means to probe the epoch of reionization (EoR), when the neutral intergalactic medium was ionized by energetic photons emitted from the first galaxies. The [C ii] 158 μm fine-structure line is typically one of the brightest emission lines of star-forming galaxies and thus a promising tracer of the global EoR star formation activity. However, [C ii] intensity maps at 6 ≲ z ≲ 8 are contaminated by interloping CO rotational line emission (3 ≤ Jupp ≤ 6) from lower-redshift galaxies. Here we present a strategy to remove the foreground contamination in upcoming [C ii] intensity mapping experiments, guided by a model of CO emission from foreground galaxies. The model is based on empirical measurements of the mean and scatter of the total infrared luminosities of galaxies at z < 3 and with stellar masses selected in the K-band from the COSMOS/UltraVISTA survey, which can be converted to CO line strengths. For a mock field of the Tomographic Ionized-carbon Mapping Experiment, we find that masking out the “voxels” (spectral–spatial elements) containing foreground galaxies identified using an optimized CO flux threshold results in a z-dependent criterion (or ) at z < 1 and makes a [C ii]/COtot power ratio of ≳10 at k = 0.1 h/Mpc achievable, at the cost of a moderate ≲8% loss of total survey volume. [ABSTRACT FROM AUTHOR]

We report measurements of the diffuse galactic light (DGL) spectrum in the near-infrared, spanning the wavelength range 0.95–1.65 μm by the Cosmic Infrared Background ExpeRiment. Using the low-resolution spectrometer calibrated for absolute spectro-photometry, we acquired long-slit spectral images of the total diffuse sky brightness toward six high-latitude fields spread over four sounding rocket flights. To separate the DGL spectrum from the total sky brightness, we correlated the spectral images with a 100 μm intensity map, which traces the dust column density in optically thin regions. The measured DGL spectrum shows no resolved features and is consistent with other DGL measurements in the optical and at near-infrared wavelengths longer than 1.8 μm. Our result implies that the continuum is consistently reproduced by models of scattered starlight in the Rayleigh scattering regime with a few large grains. [ABSTRACT FROM AUTHOR]