We present the hard-band ($2-10\,\mathrm{keV}$) X-ray luminosity function (HXLF) of $0.5-2\,\mathrm{keV}$ band selected AGN at high redshift. We have assembled a sample of 141 AGN at $3<z\lesssim5$ from X-ray surveys of different size and depth, in order to sample different regions in the $ L_X - z$ plane. The HXLF is fitted in the range $\mathrm{logL_X\sim43-45}$ with standard analytical evolutionary models through a maximum likelihood procedure. The evolution of the HXLF is well described by a pure density evolution, with the AGN space density declining by a factor of $\sim10$ from $z=3$ to 5. A luminosity-dependent density evolution model which, normally, best represents the HXLF evolution at lower redshift, is also consistent with the data, but a larger sample of low-luminosity ($\mathrm{logL_X}<44$), high-redshift AGN is necessary to constrain this model. We also estimated the intrinsic fraction of AGN obscured by a column density $\mathrm{logN_H}\geq23$ to be $0.54\pm0.05$, with no strong dependence on luminosity. This fraction is higher than the value in the Local Universe, suggesting an evolution of the luminous ($\mathrm{L_X>10^{44}\mathrm{erg\,s^{-1}}}$) obscured AGN fraction from $z=0$ to $z>3$.
NEXUS: Spectral Variability of Little Red Dots and Blue Active Galactic Nuclei at $2 \lesssim z \lesssim 6$
University of Illinois at Urbana-Champaign(伊利诺伊大学厄巴纳-香槟分校);National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign(美国国家超级计算应用中心);Princeton University(普林斯顿大学);University of Michigan(密歇根大学)
Kinematics and Structure of Clumps in Broad-line Regions in Active Galactic Nuclei
本文用无碰撞粒子系综的Jeans方程描述了宽线区(BLR)云的三种分布:(A)非盘状结构(B)盘状风结构(C)纯盘状结构。我们认为,最亮类星体中的团簇结构属于A类,较暗类星体和较亮的Seyfert星系属于B类,较暗的Seyfert星系和所有低光度活动星系核(LLAGN)属于C类。我们推导出盘状结构的维里因子$f$,并发现倾斜角$θ_{0}$和$f$之间存在负相关。我们发现类似的行为$f$作为FWHM和$σ_{z}$,速度色散的$z$组件的函数。对于不同的$θ_{0}$值,我们发现在1型活动星系核中存在$ 1.0 \lesssim f \lesssim 9.0 $,而在2型活动星系核中存在$ 0.5 \lesssim f \lesssim 1.0 $。此外,我们有$ 0.5 \lesssim f \lesssim 6.5 $的不同值的FWHM和$ 1.4 \lesssim f \lesssim 1.8 $的不同值的$ σ_{z} $。我们还发现,$ f $对各云的辐射光度和柱密度的变化相对不敏感,其变化范围为0.01量级。考虑到$ f $的广泛范围,我们认为使用平均维里因子$ \langle f \rangle $不是很安全。因此我们建议活动星系核团体根据成员的$ θ_{0}$和FWHM值将一个样本分成几个子样本,分别计算每组的$ \langle f \rangle $,以减少黑洞质…
The luminosity function and clustering of bright quasars in the FLAMINGO cosmological simulations
Leiden University(莱顿大学);The Australian National University(澳大利亚国立大学);Center for Astrophysics | Harvard & Smithsonian(哈佛-史密森天体物理中心);University of California, Santa Barbara(加州大学圣塔芭芭拉分校);Lorentz Institute for Theoretical Physics, Leiden University(莱顿大学洛伦兹理论物理研究所)
Exploring Reionization-Era Quasars III: Discovery of 16 Quasars at $6.4\lesssim z \lesssim 6.9$ with DESI Legacy Imaging Surveys and UKIRT Hemisphere Survey and Quasar Luminosity Function at $z\sim6.7$
这是一个系列中的第三篇论文,旨在通过DESI遗产成像巡天(DELS)和近红外成像巡天(如UKIRT半球巡天(UHS))以及宽场红外巡天探索($WISE$)中红外巡天的组合来寻找再电离时代的类星体。本文描述了更新的类星体候选者选择程序,报告了在$6.4\lesssim z \lesssim6.9$上从$\sim$ 13,020 deg $^2$区域发现的16个类星体,并给出了$z\sim6.7$上的类星体光度函数(QLF)。测量的QLF在幅度范围$27.6<M_{1450}<-25.5$中跟随$Φ(L_{1450})\propto L_{1450}^{-2.35}$。我们确定了$\langle z \rangle$ =6.7和$M_{1450}<-26.0$处的类星体共动空间密度为$\rm 0.39\pm0.11 Gpc^{-3}$,并发现从$z\sim6$到$z\sim6.7$的指数密度演化参数为$k=-0.78\pm0.18$,对应于向早期每单位红移迅速下降一个$\sim 6$的因子,其速度明显快于$z\sim 3- 5$处。$z\sim6$和$z\sim6.7$之间的宇宙时间只有1.21亿年。类星体密度在如此短的时间内下降了三倍以上,这要求SMBH必须迅速增长,否则它们在更高的红移下辐射效率较低。我们在$z\sim6.7$上测量了类星体的共动发射率,这表明高红移类星体不太可能对…
Toward the Standard Population Synthesis Model of the X-Ray Background: Evolution of X-Ray Luminosity and Absorption Functions of Active Galactic Nuclei Including Compton-Thick Populations
Galaxy And Mass Assembly (GAMA): $\mathbf{z \sim 0}$ Galaxy Luminosity Function down to $\mathbf{L \sim 10^{6}~L_\odot}$ via Clustering Based Redshift Inference
Formation of galactic nuclei with multiple supermassive black holes at high redshifts
我们研究了由于星系在高红移时的高合并率而在贫气体星系核中形成的多个超大质量黑洞(SMBH)群。我们计算的相对可能性的二进制,三重和四重SMBH系统,考虑相关过程的时间尺度和合并树相结合的N-体模拟的恒星和SMBH在星系核的动态。现今典型的质量为$M_0\approx 10^{14}$ M $_\odot$的晕在$z\sim 6$处的平均质量为$M_{z=6}=5\times 10^{11}$ M $_\odot$,而当前质量为$M_0\gtrsim 10^{15}$ M $_\odot$的稀有晕在该红移处的平均质量为$M_{z=6}=5\times 10^{12}$ M $_\odot$。这些星系团大小的晕被认为是$z\sim 6$中单个星系的宿主。我们预计大约30%的星系中的晕与现今的质量$M_0\approx 10^{14}$ M $_\odot$包含两个以上的SMBH在红移$2\lesssim z\lesssim 6$。对于现今较大的晕,使用$M_0\gtrsim 10^{15}$ M $_\odot$,该分数几乎为60%。在高红移处存在多个SMBH可能解释在大质量椭圆星系的核心中观察到的质量不足,这些星系的质量是其中心BH的5倍。多个SMBH也会导致恒星的潮汐分裂率提高,与孤立的BH双星相比,修改了引力波信号,并以超过2000 km/s $^{-1}$的高速从星系中弹射SM…
The $z \gtrsim 9$ galaxy UV luminosity function from the JWST Advanced Deep Extragalactic Survey: insights into early galaxy evolution and reionization
University of Arizona(亚利桑那大学);University of California, Berkeley(加州大学伯克利分校);University of California, Santa Cruz(加州大学圣克鲁兹分校);University of Texas, Austin(德克萨斯大学奥斯汀分校);University of Copenhagen(哥本哈根大学);European Space Agency(欧洲空间局)
Effects of extended components of \oiii on the correlation between the \oiii luminosity and the power-law continuum luminosity for active galactic nuclei
Metallicity of Active Galactic Nuclei from ultraviolet and optical emission lines-II. Revisiting the $C43$ metallicity calibration and its implications
Only obscured yet luminous active galactic nuclei are closely associated with galaxy mergers: Direct observational evidence from type 2 active galactic nuclei
Kyungpook National University(庆北国立大学);Sejong University(世宗大学);Pusan National University(釜山国立大学);Korea Astronomy and Space Science Institute (KASI)(韩国天体宇宙科学研究所)
Direct observational evidence that higher-luminosity type 1 active galactic nuclei are most commonly triggered by galaxy mergers
Kyungpook National University(庆北国立大学);Sejong University(世宗大学);Pusan National University(釜山国立大学);Korea Astronomy and Space Science Institute (KASI)(韩国天体宇宙科学研究所)
The cold molecular gas regulates the activity of active galactic nuclei in massive galaxies
Qujing Normal University(曲靖师范学院);Nanjing University(南京大学);Peking University(北京大学);Fudan University(复旦大学);Guangxi Minzu University(广西民族大学);Yunnan Observatories, Chinese Academy of Sciences(中国科学院云南天文台);Anqing Normal University(安庆师范大学);Kunming University(昆明学院)
VLBI Detections of Compact Nuclei in Spiral-hosted Double-lobed Radio-loud Active Galactic Nuclei (DRAGNs): Evidence for Weak Parsec-Scale Jet Activity
Ulsan National Institute of Science and Technology (UNIST)(蔚山科学技术院)
Hadronic origin of multi-TeV gamma rays and neutrinos from low-luminosity active galactic nuclei: implications of past activities of the Galactic center
低光度活动星系核(LLAGNs)中的辐射低效吸积流(RIAFs)被认为是宇宙射线和中微子源,可能对观测到的漫射中微子强度有很大贡献。我们表明,这种情况下自然预测强子多TeV的伽马射线过剩银河系中心周围。在人马座A $^*$(Sgr A $^*$)的RIAF中加速的质子逃逸并与Sgr A $^*$周围的致密分子气体相互作用,这被称为中心分子区(CMZ),并产生伽马射线和中微子。基于与IceCube数据兼容的理论模型,我们计算了CMZ的伽马射线谱,发现如果Sgr A $^*$在过去比现在更活跃,那么高能立体系统可能已经探测到了具有$\gtrsim 1$ TeV的伽马射线。我们的模型预测中微子应该来自CMZ,其光谱与伽马射线光谱相似。我们还表明,这样的伽马射线过剩,预计一些附近的星系托管LLAGN。
Variability-selected low-luminosity active galactic nuclei candidates in the 7 Ms Chandra Deep Field-South
在深X射线巡天中,已经发现了光度范围很广的活动星系核。然而,宇宙学上遥远的低光度活动星系核(LLAGN,$L_{\mathrm{X}} \lesssim 10^{42}$ erg s $^{-1}$)的识别仍然是一个挑战,由于来自宿主星系的显着污染。基于7 Ms Chandra Deep Field-South(CDF-S)调查,迄今为止最长的时间尺度($\sim 17$ years)的深X射线调查,我们利用X射线可变性选择技术来搜索在CDF-S X射线源中仍然未被识别的LLAGN。我们发现13个变量源从110个未分类的CDF-S X射线源。除了一个可能是超亮X射线源外,其余12个源的变化很可能是由于吸积超大质量黑洞造成的。这12个活动星系核候选者具有较低的本征X射线光度,中值为$7 \times10^{40}$ erg s $^{-1}$。它们通常不会被严重遮蔽,平均有效幂律光子指数为1.8。可变活动星系核在CDF-S中的比例与X射线光度无关,仅受观测到的净计数总数的限制,证实了以前的研究结果,即X射线可变性是活动星系核在很宽的光度范围内几乎无处不在的特性。对于高光度活动星系核,X射线光度与变率振幅之间存在反相关,但当光度下降到$\lesssim 10^{42}$ erg s $^{-1}$时,变率振幅不再依赖于光度。整个观测到的亮度变化趋势可以大致再现的经验AGN可变性模型的基…