论文标题
XXL-HSC：早期宇宙中AGN活动与恒星形成之间的链接（$ z \ geqslant3.5 $）
XXL-HSC: The link between AGN activity and star formation in the Early Universe ($z\geqslant3.5$)
论文作者
论文摘要
在这项工作中，我们旨在研究早期宇宙中活性银河系宿主星系的恒星形成速率。 To this end, we constructed a sample of 149 luminous ($\rm L_{2-10keV} > 10^{44}\,erg\,s^{-1}$) X-ray AGNs at $\rm z \geq3.5$ selected in three fields with different depths and observed areas (Chandra COSMOS Legacy survey, XMM-XXL North and eFEDS).我们使用可用的多波长光度法从X射线到Far-Ir构建了它们的光谱能量分布（SED）。然后，我们使用X-乘式SED拟合算法估算了恒星质量，m $ _ {*} $和AGNS的SFR。应用了几个质量标准后，我们最终获得了89个高Z来源。超过一半（55 \％）的X射线样品具有光谱红移。基于我们的分析，我们的高Z X射线AGNS生活在星系中，中位$ \ rm m _ {*} = 5.6 \ times10^{10} 〜m_ \ odot $和$ \ rm sfr _ {*}} \ yr yr yr yr yr^^{ - 1} $。大多数高Z来源（$ \ sim89 $ \％）都在恒星形成星系的主序列（MS）内部或之上。估计标准化的SFR，$ \ rm sfr_ {norm} $，被定义为AGNS与MS星系的SFR的比率，表明与非AGN恒星系统相比，AGNS的SFR的AGNS SFR增强了$ \ sim 1.8 $。将我们的结果与先前在较低红移的研究相结合，我们确认$ \ rm sfr_ {norm} $不会随红移而发展。使用特定的bhar（即$ \ rm l_x $除以$ \ rm m _ {*} $），$ \rmλ_{bhar} $，可以用作Eddington比率的迹线，我们发现大部分MS内部或高于MS的AGN具有比以上具有更高的特定要求的Agns。最后，我们发现迹象表明，最大的AGN主机星系的SFR（$ \ rm log \，（M _ {*}/ M _ \ odot）> 10^{11.5-12} $）在与M $ _*$的函数中保持大致恒定，这是M $ _*$的函数。
In this work, we aimed at investigating the star formation rate of active galactic nuclei host galaxies in the early Universe. To this end, we constructed a sample of 149 luminous ($\rm L_{2-10keV} > 10^{44}\,erg\,s^{-1}$) X-ray AGNs at $\rm z \geq3.5$ selected in three fields with different depths and observed areas (Chandra COSMOS Legacy survey, XMM-XXL North and eFEDS). We built their spectral energy distributions (SED) using available multi-wavelength photometry from X-rays up to far-IR. Then, we estimated the stellar mass, M$_{*}$, and the SFR of the AGNs using the X-CIGALE SED fitting algorithm. After applying several quality criteria, we ended up with 89 high-z sources. More than half (55\%) of the X-ray sample have spectroscopic redshifts. Based on our analysis, our high-z X-ray AGNs live in galaxies with median $\rm M_{*}=5.6 \times10^{10}~M_\odot$ and $\rm SFR_{*}\approx240\,M_\odot yr^{-1}$. The majority of the high-z sources ($\sim89$\%) were found inside or above the main sequence (MS) of star-forming galaxies. Estimation of the normalised SFR, $\rm SFR_{NORM}$, defined as the ratio of the SFR of AGNs to the SFR of MS galaxies, showed that the SFR of AGNs is enhanched by a factor of $\sim 1.8$ compared to non-AGN star-forming systems. Combining our results with previous studies at lower redshifts, we confirmed that $\rm SFR_{NORM}$ does not evolve with redshift. Using the specific BHAR (i.e., $\rm L_X$ divided by $\rm M_{*}$), $\rm λ_{BHAR}$, that can be used as a tracer of the Eddington ratio, we found that the bulk of AGNs that lie inside or above the MS have higher specific accretion rates compared to sources below the MS. Finally, we found indications that the SFR of the most massive AGN host galaxies ($\rm log\,(M_{*}/ M_\odot) >10^{11.5-12}$) remains roughly constant as a function of M$_*$, in agreement with the SFR of MS star-forming galaxies.
