利用GAMA、WISE、GALEX和DESI Legacy Survey的多波段数据解耦恒星质量与环境对eROSITA AGN活动的影响
Disentangling Stellar Mass and Environmental Effects on eROSITA AGN Activity using multi-wavelength data from GAMA, WISE, GALEX, and DESI Legacy Survey
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中文总结 AI 辅助
本研究利用约36,000个星系样本，提出新型过密度度量δ_rank，发现X射线AGN比例随环境密度从约4%升至6%，而WISE选择AGN无此依赖，表明约5 Mpc尺度环境调控X射线AGN触发。
中文摘要 AI 辅助
我们使用来自GAMA/eFEDS的约36,000个恒星质量完备星系样本，检验AGN活动是否独立于恒星质量而依赖于环境。为隔离这一效应，我们引入了δ_rank，一种在窄恒星质量区间内定义的新型局部过密度度量。我们的主要结果是，X射线选择的AGN显示出明显的环境趋势，AGN比例从低密度区域的约4%上升至高密度区域的约6%，在δ_rank约0.4处出现急剧转变。这种环境依赖性在WISE选择和宽线AGN中不存在，且爱丁顿比率在不同环境中没有变化。我们还发现，对于恒星形成率（SFR）>15 M_sun/yr的星系，X射线AGN比例在低、中、高δ_rank星系中分别约为5%、60%和20%。我们表明，AGN比例与SFR之间的关系随环境和选择方法的不同而显著变化。我们得出结论，约5 h^-1 Mpc尺度上的环境调控着X射线AGN的触发效率。
英文摘要
We use a stellar-mass complete sample of $\sim 36{,}000$ galaxies from GAMA/eFEDS to test whether AGN activity depends on environment independent of stellar mass. To isolate this effect, we introduce $δ_{\rm rank}$, a novel local overdensity metric defined within narrow stellar mass bins. Our main result is that X-ray-selected AGNs show a clear environmental trend, the AGN fraction rises from $\sim 4\%$ in low-density regions to $\sim 6\%$ in high-density regions, with a sharp transition at $δ_{\rm rank} \sim 0.4$. This environmental dependence is absent for WISE-selected and broad-line AGN, and Eddington ratios show no variation across environments. We also found that for galaxies with $\mathrm{SFR} > 15\,M_\odot\,\mathrm{yr}^{-1}$, X-ray AGN fraction is approximately 5%, 60% and 20% in low, mid and high $δ_{\rm rank}$ galaxies. We show that relationship between AGN fraction and SFR varies dramatically with both environment and selection method. We conclude that environment on scales of $\sim 5h^{-1}\,\mathrm{Mpc}$ regulates X-ray AGN triggering efficiency.
发表机构
- IIT Hyderabad（印度理工学院海德拉巴分校）
- Tata Institute of Fundamental Research（塔塔基础研究所）
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