Effective model for line intensity mapping: Auto- and cross-power spectra in the cosmic dawn and reionization

Line intensity mapping (LIM) is emerging as a powerful probe of the high-redshift Universe, with a growing number of LIM experiments targeting various spectral lines deep into the epochs of reionization and cosmic dawn. A key remaining challenge is the consistent and efficient modeling of the diverse emission lines and of the observables of different surveys. Here, we present olimpus, a fully analytical effective model to study LIM auto- and cross-power spectra. Our work builds on the 21-cm effective model presented in zeus21, applying it to star-forming lines and improving it in different aspects. Our code accounts for shot noise and linear redshift-space distortions and it includes by default prescriptions for OII, OIII, $\mathrm{H}\ensuremath{\alpha}$, $\mathrm{H}\ensuremath{\beta}$, CII, CO line luminosities, together with the 21-cm model inherited from zeus21. Beyond auto- and cross-power spectra, olimpus can produce mock coeval boxes and light cones, and with a computational time of $\ensuremath{\sim}s$ it is ideal for parameter-space exploration and inference. Its modular implementation makes it easy to customize and extend, enabling various applications, such as Markov chain Monte Carlo analyses and consistent multiline cross-correlations.