Evidence for Merger-Driven Growth in Luminous, High-z, Obscured AGN in the CANDELS/COSMOS Field
J. L. Donley, J. Kartaltepe, D. Kocevski, M. Salvato, P. Santini, H. Suh, F. Civano, A. M. Koekemoer, J. Trump, M. Brusa, C. Cardamone, A. Castro, M. Cisternas,… 展开作者
J. L. Donley, J. Kartaltepe, D. Kocevski, M. Salvato, P. Santini, H. Suh, F. Civano, A. M. Koekemoer, J. Trump, M. Brusa, C. Cardamone, A. Castro, M. Cisternas, C. Conselice, D. Croton, N. Hathi, C. Liu, R. A. Lucas, P. Nair, D. Rosario, D. Sanders, B. Simmons, C. Villforth, D. M. Alexander, E. F. Bell, S. M. Faber, N. A. Grogin, J. Lotz, D. H. McIntosh, T. Nagao
虽然大合并长期以来一直被认为是活动星系核活动和M-σ关系的驱动力，但对中高红移塞弗光度活动星系核宿主的研究几乎没有发现相互作用速率增强的证据。然而，理论和观测都表明，虽然这些活动星系核可能是由随机吸积和长期过程，高光度，高红移，严重模糊的活动星系核是最有可能是合并驱动的活动星系核。为了更好地对活动星系核进行采样，我们转向CANDELS/COSMOS领域的红外选择。与低光度和低遮蔽度的X射线活动星系核相比，只有红外线的活动星系核（明亮、严重遮蔽的活动星系核）更可能被归类为不规则（50 $^{+12}_{-12}$ % vs. 9 $^{+5}_{-2}$ %）或不对称（69 $^{+9}_{-13}$ % vs. 17 $^{+6}_{-4}$ %），并且不太可能有球状成分（31 $^{+13}_{-9}$ % vs. 77 $^{+4}_{-6}$ %）。此外，只有红外线的活动星系核也比只有X射线的活动星系核（75 $^{+8}_{-13}$ % vs. 31 $^{+6}_{-6}$ %）更有可能被归类为相互作用或合并，以一种显著干扰宿主星系的方式，或者被干扰但没有明显的相互作用或合并，这可能代表了一个大合并的后期阶段。这表明，虽然主要的合并可能不会显着贡献的塞弗特光度活动星系核的燃料，相互作用似乎发挥更主导的作用，在触发和燃料的高光度严重模糊的活动星系核。
英文摘要：
While major mergers have long been proposed as a driver of both AGN activity and the M-sigma relation, studies of moderate to high redshift Seyfert-luminosity AGN hosts have found little evidence for enhanced rates of interactions. However, both theory and observation suggest that while these AGN may be fueled by stochastic accretion and secular processes, high-luminosity, high-redshift, and heavily obscured AGN are the AGN most likely to be merger-driven. To better sample this population of AGN, we turn to infrared selection in the CANDELS/COSMOS field. Compared to their lower-luminosity and less obscured X-ray-only counterparts, IR-only AGN (luminous, heavily obscured AGN) are more likely to be classified as either irregular (50$^{+12}_{-12}$% vs. 9$^{+5}_{-2}$%) or asymmetric (69$^{+9}_{-13}$% vs. 17$^{+6}_{-4}$%) and are less likely to have a spheroidal component (31$^{+13}_{-9}$% vs. 77$^{+4}_{-6}$%). Furthermore, IR-only AGN are also significantly more likely than X-ray-only AGN (75$^{+8}_{-13}$% vs. 31$^{+6}_{-6}$%) to be classified either as interacting or merging in a way that significantly disturbs the host galaxy or disturbed though not clearly interacting or merging, which potentially represents the late stages of a major merger. This suggests that while major mergers may not contribute significantly to the fueling of Seyfert luminosity AGN, interactions appear to play a more dominant role in the triggering and fueling of high-luminosity heavily obscured AGN.
Morphology and structure of extremely red objects at $z\sim1$ in the CANDELS-COSMOS field
利用CANDELS-COSMOS场的高分辨率HST/Wide Field Camera 3 F125 W成像，我们报道了$z\sim1$极红天体（ERO）的结构和形态特征。基于UVJ色标准，我们将ERO分为两类：古老的被动星系（OG）和尘埃恒星形成星系（DG）。对于给定的恒星质量，我们发现在静止坐标系光波长下，OGs（DGs）的平均尺寸比现今早型（晚型）星系的平均尺寸小$\sim2$（1.5）倍。我们推导了OG和DG的平均有效半径，分别对应于$2.09\pm1.13$ kpc和$3.27\pm1.14$ kpc。一般来说，DG是不均匀的，具有包括凸起、盘状和不规则结构的混合特征，具有相对高的$M_{\rm 20}$、小尺寸和低$G$，而OG是椭圆状的紧凑形态，具有较低的$M_{\rm 20}$、较大的尺寸和较高的$G$，这表明在OG中恒星星族分布的空间范围比DG更集中和对称。研究结果表明，OGs和DG具有不同的演化过程，小合并情景是OGs结构特性的最可能机制。然而，星系的尺度演化可能是由于星系的长期演化。
We analyze morphologies of the host galaxies of 35 X-ray selected active galactic nucleus (AGNs) at $z\sim2$ in the Cosmic Evolution Survey (COSMOS) field using Hubble Space Telescope/WFC3 imaging taken from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). We build a control sample of 350 galaxies in total, by selecting ten non-active galaxies drawn from the same field with the similar stellar mass and redshift for each AGN host. By performing two dimensional fitting with GALFIT on the surface brightness profile, we find that the distribution of S$è$rsic index (n) …
S-CANDELS: The Spitzer-Cosmic Assembly Near-Infrared Deep Extragalactic Survey. Survey Design, Photometry, and Deep IRAC Source Counts
斯皮策宇宙大会深近红外河外遗产调查（S-CANDELS; PI G。Fazio）是一个第8周期的探索计划，旨在探测非常高红移（z > 5）的星系。为了减轻宇宙变化的影响，并利用哈勃空间望远镜多周期财政计划CANDELS在多个波段的深度同延覆盖，S-CANDELS在五个相距甚远的河外区域进行：UKIDSS超深巡天、扩展钱德拉深场南、COSMOS、HST深场北和扩展格罗斯带。S-CANDELS建立在斯皮策扩展深度调查（SEDS）现有的这些领域的覆盖范围之上，将积分时间从12小时增加到总共50小时，但在较小的区域内，0.16平方度。额外的深度显著增加了微弱星等下的勘测完整性。本文介绍了S-CANDELS调查的设计、处理和公开提供的数据产品。我们目前的IRAC双波段3.6+4.5微米目录达到26.5 AB MAG的深度。深IRAC计数的大约135,000个星系检测的S-CANDELS是一致的模型的基础上已知的星系种群。比早期斯皮策/IRAC调查更深的深度增加并没有揭示离散源对弥漫的宇宙红外背景（CIB）的显着额外贡献。因此，它仍然是正确的，只有大约一半的估计CIB通量从COBE/DIRBE解决。
We present band 6 ALMA observations of a heavily-obscured radio-loud ($L_{1.4\ \mathrm{GHz}}=10^{25.4}$ W Hz$^{-1}$) AGN candidate at $z_\mathrm{phot}=6.83\pm0.06$ found in the 1.5 deg$^2$ COSMOS field. The ALMA data reveal detections of exceptionally strong [CII]158$μ$m ($z_\mathrm{[CII]}=6.8532$) and underlying dust continuum emission from this object (COS-87259), where the [CII] line luminosity, line width, and 158$μ$m continuum luminosity are comparable to that seen from $z\sim7$ sub-mm galaxies and quasar hosts. The 158$μ$m continuum detection suggests a total infrared luminosity of $9\ti…
Using the CANDELS photometric catalogs for the HST/ACS and WFC3, we identified massive evolved galaxies at $3 < z < 4.5$, employing three different selection methods. We find the comoving number density of these objects to be $\sim 2 \times 10^{-5}$ and $8 \times 10^{-6}Mpc^{-3}$ after correction for completeness for two redshift bins centered at $z=3.4, 4.7$. We quantify a measure of how much confidence we should have for each candidate galaxy from different selections and what are the conservative error estimates propagated into our selection. Then we compare the evolution of the correspondi…
We present ASTRODEEP-GS43, a new multiwavelength photometric catalogue of the GOODS-South field, which builds and improves upon the previously released CANDELS catalogue. We provide photometric fluxes and corresponding uncertainties in 43 optical and infrared bands (25 wide and 18 medium filters), as well as photometric redshifts and physical properties of the 34930 CANDELS $H$-detected objects, plus an additional sample of 178 $H$-dropout sources, of which 173 are $Ks$-detected and 5 IRAC-detected. We keep the CANDELS photometry in 7 bands (CTIO $U$, Hubble Space Telescope WFC3 and ISAAC-$K$)…
Beyond the Brightest: A Deep Learning Approach to Identifying Major and Minor Galaxy Mergers in CANDELS at $z \sim 1$
University of Colorado, Boulder（科罗拉多大学博尔德分校）；Fermi National Accelerator Laboratory（费米国家加速器实验室）；University of Chicago（芝加哥大学）；NSF-Simons AI Institute for the Sky (SkAI)（美国国家科学基金会-西蒙斯天空人工智能研究所）；California Institute of Technology（加州理工学院）；Massachusetts Institute of Technology（麻省理工学院）；Vanderbilt University（范德堡大学）；University of Florida（佛罗里达大学）
It is a widespread opinion that hydrogen reionization is mainly driven by primeval star-forming galaxies, with a minor role of high-z active galactic nuclei. Recent observations, however, challenge this notion, indicating a number of issues related to a galaxy-driven reionization scenario. We provide here an updated assessment of the space density of relatively faint (M1450~-22.5) AGNs at zspec~5.5 in order to improve the estimate of the photo-ionization rate contribution from accreting super massive black holes. Exploiting deep UV rest-frame ground-based spectra collected at the Very Large Te…
A complete census of Active Galactic Nuclei (AGN) is a prerequisite for understanding the growth of supermassive black holes across cosmic time. A significant challenge toward this goal is the whereabouts of heavily obscured AGN that remain uncertain. This paper sets new constraints on the demographics of this population by developing a methodology that combines X-ray spectral information with priors derived from multiwavelength observations. We select X-ray AGN in the Chandra COSMOS Legacy survey and fit their $2.2-500μm$ spectral energy distributions with galaxy and AGN templates to determin…
To understand the Active Galactic Nuclei (AGN) phenomenon and their impact on the evolution of galaxies, a complete AGN census is required; however, finding heavily obscured AGNs is observationally challenging. Here we use the deep and extensive multi-wavelength data in the COSMOS field to select a complete sample of 578 infrared (IR) quasars ($L_{\rm AGN,IR}>10^{45}\rm \: erg\: s^{-1}$) at $z<3$, with minimal obscuration bias, using detailed UV-to-far IR spectral energy distribution (SED) fitting. We complement our SED constraints with X-ray and radio observations to further investigate the p…
Many X-ray bright active galactic nuclei (AGN) are predicted to follow an extended stage of obscured black hole growth. In support of this picture we examine the X-ray undetected AGNs in the COSMOS field and compare their host galaxies with X-ray bright AGNs. We examine galaxies with M_\ast>10^{9.5}M_\odot for the presence of AGNs at redshifts $z=0.5-3$. We select AGNs in the infrared using \textit{Spitzer} and \textit{Herschel} detections and use color selection techniques to select AGNs within strongly star forming hosts. We stack \textit{Chandra} X-ray data of galaxies with an IR detection …
Near-IR Weak-lensing (NIRWL) Measurements in the CANDELS Fields. II. Mass Mapping and Overdensity Characterization
IPAC, California Institute of Technology（加州理工学院 IPAC）；Korea Astronomy and Space Science Institute (KASI)（韩国天体宇宙科学研究所）；SPACE Institute, University of California（加州大学 SPACE 研究所）；Institute for Astronomy, University of Edinburgh（爱丁堡大学天文研究所）；Department of Physics, Duke University（杜克大学物理系）；Department of Astronomy, Yonsei University（延世大学天文学系）；Department of Physics and Astronomy, University of California, Davis（加州大学戴维斯分校物理与天文学系）；Center for Cosmology and Astroparticle Physics, The Ohio State University（俄亥俄州立大学宇宙学与高能粒子物理中心）；Department of Physics, The Ohio State University（俄亥俄州立大学物理系）；Department of Astronomy, The Ohio State University（俄亥俄州立大学天文学系）
In this work we report the discovery of the hyperluminous galaxy HELP_J100156.75+022344.7 at the photometric redshift of z ~ 4.3. The galaxy was discovered in the Cosmological Evolution Survey (COSMOS) field, one of the fields studied by the Herschel Extragalactic Legacy Project (HELP). We present the spectral energy distribution (SED) of the galaxy and fit it with the CYprus models for Galaxies and their NUclear Spectra (CYGNUS) multi-component radiative transfer models. We find that its emission is dominated by an obscured quasar with a predicted total 1-1000um luminosity of $3.91^{+1.69}_{-…
Evolution of the infrared luminosity function and its corresponding dust-obscured star formation rate density out to z~6
Institute of Astronomy, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University（尼古拉·哥白尼大学物理、天文与信息学学院天体物理研究所）；National Centre for Nuclear Research（国家核研究中心）；Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh（爱丁堡大学天体物理研究所皇家天文台）；Astronomical Observatory Institute, Faculty of Physics and Astronomy, Adam Mickiewicz University（亚当·密茨凯维奇大学物理与天文学学院天文台研究所）
