2005ApJ...623L..97T

We use the observed number and column density distributions of intergalactic O VI absorbers to constrain the distribution of metals in the low-redshift intergalactic medium (IGM). In this simple model, the metals in the O VI absorbers are assumed to be produced in and propagated from low-redshift galaxies drawn from a real sample, in this case the Sloan Digital Sky Survey. This model can explain the observed dN/dz of metals borne by O VI absorbers if these metals are dispersed out to ∼200 kpc by galaxies down to L∼0.01-0.1L^*_r. Massive galaxies (L∼L^*_r) by themselves cannot provide the metals unless they can enrich volumes out to ≳0.5-1 Mpc. This model suggests that the turnover in dN/dNdz below logN(O VI)≃13.5 (W_λ=50 mÅ) is likely a real effect resulting from the apparently limited volumes over which galaxies can disperse metals, rather than a consequence of survey incompleteness. If so, it would indicate that metals are not as widespread throughout the IGM, as they are assumed to be in cosmological simulations of the warm-hot IGM. Alternatively, our model estimates the fraction of O VI absorbers directly caused by galaxies, such as the known populations of highly ionized high-velocity clouds surrounding the Milky Way, rather than the hot IGM.