2026/07/21 by Derick Flores, Rongmon Bordoloi, Jason Tumlinson +12
#astro-ph.GA
We present the GOLIATH survey (Galaxies, Outflows, and the Lifecycle of Immense, Active, Transforming Halos), a study of the multiphase circumgalactic medium (CGM) of massive (⟨log M_⋆/M_\odot⟩ ≈ 11), blue (u-r < 1.65) starburst and post-starburst galaxies at ⟨ z⟩ ≈ 0.43. This work characterizes the warm-hot CGM through OVI absorption in the inner halo (R/R\rm vir ≤ 0.6) of these rare systems. Across the star-forming population, OVI column density rises by nearly 1~dex from log M_⋆/M\odot ∼ 8 to ∼ 11.5 and increases with specific star-formation rate (sSFR). Two GOLIATH galaxies with the highest sSFR show the strongest CGM OVI absorption (log N\rm O VI[\rm cm-2] \gtrsim 15). In the log M_⋆/M\odot = [11,12) inner-CGM region, massive star-forming galaxies exceed quiescent galaxies on average by a factor of ∼ 3 in OVI column density and ∼ 1.5~dex in CGM OVI mass (log(M\rm O VI/M_\odot) ≈ 7.3 versus ≈ 5.8), with covering fractions roughly three times higher (62.5% versus 24% at log N\rm O VI[\rm cm-2] ≥ 14). The OVI line widths and column densities are consistent with feedback-driven radiative cooling, in which outflow shocks heat the CGM and the gas cools back through the OVI window; the short cooling time, t\rm cool ∼ 10-100~Myr, requires continuous replenishment by active feedback to sustain this reservoir. The residual OVI in quiescent systems may arise from ambient gas at the high-temperature end of the cooling curve. OVI thus traces feedback on short timescales and probes the star-forming--quiescent transition at log M_⋆/M\odot \gtrsim 11.