Dust thermalization temperature and CMB anisotropy impact from massive ETG formation

Determine the precise thermalization temperature of dust in massive early-type galaxies during their rapid formation at high redshift (approximately 15–20) and quantify how the resulting dust-processed radiation impacts the observed cosmic microwave background anisotropies after redshifting to the present epoch.

Background

The paper argues that massive early-type galaxies formed very rapidly and with top-heavy galaxy-wide initial mass functions at redshifts around 15–20, producing extremely high bolometric luminosities. Given rapid chemical enrichment and dust formation, the authors posit that this radiation would have been efficiently thermalized by dust, yielding a photon field that could contribute significantly to today’s CMB energy density after cosmological redshift.

While the authors provide order-of-magnitude estimates (e.g., effective dust temperatures near 50 K under fiducial assumptions), they explicitly leave the precise determination of the dust thermalization temperature and its quantitative effect on CMB anisotropies for future work. Resolving these quantities is essential to assess whether early massive ETG formation constitutes a significant foreground component that biases CMB analyses.