Neutrino Properties with Ground-based Millimeter-wavelength Line Intensity Mapping

Abstract

Line intensity mapping (LIM) is emerging as a powerful technique to map the cosmic large-scale structure and to probe cosmology over a wide range of redshifts and spatial scales. We perform Fisher forecasts to determine the optimal design of wide-field ground-based millimeter-wavelength LIM surveys for constraining properties of neutrinos and light relics. We consider measuring the auto-power spectra of several CO rotational lines (from J = 2–1 to J = 6–5) and the [C ii] fine-structure line in the redshift range of 0.25 < z < 12. We study the constraints with and without interloper lines as a source of noise in our analysis, and for several one-parameter and multiparameter extensions of ΛCDM. We show that LIM surveys deployable this decade, in combination with existing cosmic microwave background (CMB; primary) data, could achieve order-of-magnitude improvements over Planck constraints on N eff and M ν . Compared to next-generation CMB and galaxy surveys, a LIM experiment of this scale could achieve bounds that are a factor of ∼3 better than those forecasted for surveys such as EUCLID (galaxy clustering), and potentially exceed the constraining power of CMB-S4 by a factor of ∼1.5 and ∼3 for N eff and M ν , respectively. We show that the forecasted constraints are not substantially affected when enlarging the parameter space, and additionally demonstrate that such a survey could also be used to measure ΛCDM parameters and the dark energy equation of state exquisitely well.

Snowmass2021 Cosmic Frontier White Paper: Cosmology and Fundamental Physics from the three-dimensional Large Scale Structure

“…In what follows, we will make explicit forecasts for galaxy surveys and 21 cm intensity mapping to compare the strengths of different techniques. Since the forecasts for those and for LIM are not performed using the same forecasting machinery [30,31], we do not report the LIM forecasts directly. We note that LIM will share many of the same features with 21 cm that stem from the need to perform foreground filtering.…”

Snowmass 2021 Cosmic Frontier White Paper: Cosmology with Millimeter-Wave Line Intensity Mapping

“…The constraints are obtained using a unified Fisher Forecast pipeline described in Ref. [17], where further details about the signal and interloper modeling, instrument noise, and forecasting assumptions are outlined.…”

“…The same large-scale cut is set as in the parameter forecasts. Instrumental noise is computed as in [17], and interlopers are accounted for as additional noise terms. Figure 4 shows the FoM as a function of maximum observed redshift Cosmology with mm-wave line intensity mapping for ∼ 4 × 10 9 spectrometer-hours, for each individual line and their combination.…”

Cosmological Constraints on the Global Star Formation Law of Galaxies: Insights from Baryon Acoustic Oscillation Intensity Mapping

“…In particular, the tight connection between the emission line production and the astrophysics of interstellar gas of galaxies makes LIM a promising statistical probe of galaxy evolution. Historically, large-scale fluctuations of line intensity fields have been mainly considered for cosmological applications, such as probing alternative dark matter models, dark energy, gravitational lensing, neutrino properties, and the primordial non-Gaussianity (e.g., Sitwell et al 2014;Karkare & Bird 2018;Bernal et al 2019;Liu & Breysse 2021;Chung 2022;Maniyar et al 2022;Moradinezhad Dizgah et al 2022). The majority of astrophysical explorations of LIM have been focusing on small, nonlinear scales, where astrophysical processes of galaxy evolution are manifested through their effects on the one-halo or shot-noise components of the LIM power spectrum (e.g., Wolz et al 2017;Breysse & Alexandroff 2019;Mas-Ribas & Chang 2020;Schaan & White 2021).…”