戈利亚斯巡天：通过大质量星系从星暴到宁静的转变中氧离子吸收揭示星系冕演化
The GOLIATH Survey: OVI Absorption Reveals CGM Evolution through the Starburst-to-Quiescent Transition in Massive Galaxies
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中文总结 AI 辅助
戈利亚斯巡天通过氧离子吸收研究大质量星系的多相星系冕介质，揭示其在星暴到宁静转变中的演化，发现恒星形成星系氧离子柱密度等与sSFR有关，氧离子可追踪反馈及探测星静转变。
中文摘要 AI 辅助
我们展示了戈利亚斯巡天（星系、外流与巨大、活跃、转变晕的生命周期），这是一项对红移约为0.43、质量大（$\langle\log M_\star/M_\odot\rangle \approx 11$）、蓝色（$u - r < 1.65$）的星暴和星暴后星系的多相星系冕介质（CGM）的研究。这项工作通过这些罕见星系内晕（$R/R_{\rm vir} \leq 0.6$）中的氧离子吸收来表征温热的CGM。在整个恒星形成星系群体中，氧离子柱密度从$\log M_\star/M_{\odot} \sim 8$到$\sim 11.5$上升近1个量级，并随特定恒星形成率（sSFR）增加。两个sSFR最高的戈利亚斯星系显示出最强的CGM氧离子吸收（$\log N_{\rm O\,VI}[\rm cm^{-2}] \gtrsim 15$）。在$\log M_\star/M_{\odot} = [11,12)$的内CGM区域，大质量恒星形成星系的氧离子柱密度平均比宁静星系高约3倍，CGM氧离子质量高约1.5个量级（$\log(M_{\rm O\, VI}/M_\odot) \approx 7.3$对$\approx 5.8$），覆盖分数大约高三倍（在$\log N_{\rm O\,VI}[\rm cm^{-2}] \geq 14$时为62.5%对24%）。氧离子线宽和柱密度与反馈驱动的辐射冷却一致，其中外流激波加热CGM，气体通过氧离子窗口冷却回来；短冷却时间$t_{\rm cool} \sim 10$ - $100$百万年，需要活跃反馈持续补充以维持这个储备。宁静系统中的残余氧离子可能来自冷却曲线高温端的环境气体。因此，氧离子在短时间尺度上追踪反馈，并探测$\log M_\star/M_{\odot} \gtrsim 11$时的恒星形成到宁静的转变。
英文摘要
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 ($\langle\log M_\star/M_\odot\rangle \approx 11$), blue ($u-r < 1.65$) starburst and post-starburst galaxies at $\langle z\rangle \approx$ 0.43. This work characterizes the warm-hot CGM through OVI absorption in the inner halo ($R/R_{\rm vir} \leq 0.6$) of these rare systems. Across the star-forming population, OVI column density rises by nearly 1~dex from $\log M_\star/M_{\odot} \sim 8$ to $\sim 11.5$ 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 $\log M_\star/M_{\odot} = [11,12)$ inner-CGM region, massive star-forming galaxies exceed quiescent galaxies on average by a factor of $\sim 3$ in OVI column density and $\sim 1.5$~dex in CGM OVI mass ($\log(M_{\rm O\, VI}/M_\odot) \approx 7.3$ versus $\approx 5.8$), with covering fractions roughly three times higher (62.5% versus 24% at $\log N_{\rm O\,VI}[\rm cm^{-2}] \geq 14$). 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, $t_{\rm cool} \sim 10$-$100$~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 $\log M_\star/M_{\odot} \gtrsim 11$.
