A view of the narrow-line region in the infrared: active galactic nuclei with resolved fine-structure lines in the Spitzer archive

We queried the Spitzer archive for high-resolution observations with the Infrared Spectrograph of optically selected active galactic nuclei (AGN) for the purpose of identifying sources with resolved fine-structure lines that would enable studies of the narrow-line region (NLR) at mid-infrared wavelengths. By combining 298 Spitzer spectra with 6 Infrared Space Observatory spectra, we present kinematic information of the NLR for 81 z<=0.3 AGN. We used the [NeV], [OIV], [NeIII], and [SIV] lines, whose fluxes correlate well with each other, to probe gas photoionized by the AGN. We found that the widths of the lines are, on average, increasing with the ionization potential of the species that emit them. No correlation of the line width with the critical density of the corresponding transition was found. The velocity dispersion of the gas, sigma, is systematically higher than that of the stars, sigma_*, in the AGN host galaxy, and it scales with the mass of the central black hole, M_BH. Further correlations between the line widths and luminosities L, and between L and M_BH, are suggestive of a three dimensional plane connecting log(M_BH) to a linear combination of log(sigma) and log(L). Such a plane can be understood within the context of gas motions that are driven by AGN feedback mechanisms, or virialized gas motions with a power-law dependence of the NLR radius on the AGN luminosity. The M_BH estimates obtained for 35 type 2 AGN from this plane are consistent with those obtained from the M_BH-sigma_* relation.Comment: ApJ, revised to match the print versio

The Research On Space Design Method Of University Library In Digital Age-- The Library Design Of Xiamen University, Malaysia

作为信息整合、传播的重要“窗口”，大学图书馆在数字时代快速发展的信息技术、网络应用的影响下，其功能、空间发生了一系列变化，逐渐从单一功能演变为信息媒体中心、多元学习中心、多功能交流中心以及文化艺术中心，具有全新的时代定义，成为容纳学习、科研、休闲等多种功能的复合型空间。在这种情形下，通过空间建构方式的研究使大学图书馆空间更适应数字时代带来的变化，具有理论及实践两方面的重要意义。 本文将分析数字时代大学图书馆功能的再定义，探讨空间的转变问题，最后总结出空间建构方式；同时，理论与设计实践相结合，完成厦门大学马来西亚分校图书馆空间设计。论文主要分为三部分： 第一章绪论是为第一部分，主要交待论文的...As an important “window” for information integration and transmission,university library made a series of changes of its function and space under the influence of rapid development of digital information technology and network application .It gradually evolved from a single function building to information media center, multiple learning center, multi-functional exchange center and cultural arts c...学位：建筑学硕士院系专业：建筑与土木工程学院_建筑设计及其理论学号：2522011115170

An Over-Massive Black Hole in a Typical Star-Forming Galaxy, 2 Billion Years After the Big Bang

Supermassive black holes (SMBHs) and their host galaxies are generally thought to coevolve, so that the SMBH achieves up to about 0.2 to 0.5% of the host galaxy mass in the present day. The radiation emitted from the growing SMBH is expected to affect star formation throughout the host galaxy. The relevance of this scenario at early cosmic epochs is not yet established. We present spectroscopic observations of a galaxy at redshift z = 3.328, which hosts an actively accreting, extremely massive BH, in its final stages of growth. The SMBH mass is roughly one-tenth the mass of the entire host galaxy, suggesting that it has grown much more efficiently than the host, contrary to models of synchronized coevolution. The host galaxy is forming stars at an intense rate, despite the presence of a SMBH-driven gas outflow.Comment: Author's version, including the main paper and the Supplementary Materials (16+21 pages, 3+3 figures

Compton-thick accretion in the local universe

Heavily obscured accretion is believed to represent an important stage in the growth of supermassive black holes and to play an important role in shaping the observed spectrum of the cosmic X-ray background. Hard X-ray (E &gt; 10 keV) selected samples are less affected by absorption than samples selected at lower energies, and are therefore one of the best ways to detect and identify Compton-thick (CT, log NH ≥ 24) active galactic nuclei (AGNs). In this letter we present the first results of the largest broadband (0.3–150 keV) X-ray spectral study of hard X-ray selected AGNs to date, focusing on the properties of heavily obscured sources. Our sample includes the 834 AGNs (728 non-blazar, average redshift z sime 0.055) reported in the 70-month catalog of the all-sky hard X-ray Swift/Burst Alert Monitor survey. We find 55 CT AGNs, which represent 7.6-2.1+1.1 % of our non-blazar sample. Of these, 26 are reported as candidate CT AGNs for the first time. We correct for selection bias and derive the intrinsic column density distribution of AGNs in the local universe in two different luminosity ranges. We find a significant decrease in the fraction of obscured Compton-thin AGNs for increasing luminosity, from 46 ± 3% (for log L14-195 = 40–43.7) to 39 ± 3% (for log L14-195 = 43.7–46). A similar trend is also found for CT AGNs. The intrinsic fraction of CT AGNs with log NH = 24–25 normalized to unity in the NH = 20–25 range is 27 ± 4%, and is consistent with the observed value obtained for AGNs located within 20 Mpc

Fast-Growing SMBHs in Fast-Growing Galaxies, at High Redshifts: The Role of Major Mergers As Revealed by ALMA

We present a long-term, multi-wavelength project to understand the epoch of fastest growth of the most massive black holes by using a sample of 40 luminous quasars at z~4.8. These quasars have rather uniform properties, with typical accretion rates and black hole masses of L/L_Edd~0.7 and M_BH~10^9 M_sol. The sample consists of "FIR-bright" sources with a previous Herschel/SPIRE detection, suggesting SFR > 1000 M_sol/yr, as well as of "FIR-faint" sources for which Herschel stacking analysis implies a typical SFR of ~400 M_sol/yr. Six of the quasars have been observed by ALMA in [CII]{\lambda}157.74 micron line emission and adjacent rest-frame 150 micron continuum, to study the dusty cold ISM. ALMA detected companion, spectroscopically confirmed sub-mm galaxies (SMGs) for three sources - one FIR-bright and two FIR-faint. The companions are separated by ~14-45 kpc from the quasar hosts, and we interpret them as major galaxy interactions. Our ALMA data therefore clearly support the idea that major mergers may be important drivers for rapid, early SMBH growth. However, the fact that not all high-SFR quasar hosts are accompanied by interacting SMGs, and their ordered gas kinematics observed by ALMA, suggest that other processes may be fueling these systems. Our analysis thus demonstrates the diversity of host galaxy properties and gas accretion mechanisms associated with early and rapid SMBH growth

The fraction of AGN in major merger galaxies and its luminosity dependence

We use a phenomenological model which connects the galaxy and AGN populations to investigate the process of AGN triggering through major galaxy mergers at z~0. The model uses stellar mass functions as input and allows the prediction of AGN luminosity functions based on assumed Eddington ratio distribution functions (ERDFs). We show that the number of AGN hosted by merger galaxies relative to the total number of AGN increases as a function of AGN luminosity. This is due to more massive galaxies being more likely to undergo a merger and does not require the assumption that mergers lead to higher Eddington ratios than secular processes. Our qualitative analysis also shows that to match the observations, the probability of a merger galaxy hosting an AGN and accreting at a given Eddington value has to be increased by a factor ~10 relative to the general AGN population. An additional significant increase of the fraction of high Eddington ratio AGN among merger host galaxies leads to inconsistency with the observed X-ray luminosity function. Physically our results imply that, compared to the general galaxy population, the AGN fraction among merger galaxies is ~10 times higher. On average, merger triggering does however not lead to significantly higher Eddington ratios.Comment: 11 pages, 3 figues, accepted for publication in MNRA

Magnetic fields and gas flows around circumnuclear starbursts

Radio continuum observations of barred galaxies revealed strong magnetic fields of >= 50-100 muG in the circumnuclear starbursts. Such fields are dynamically important and give rise to magnetic stress that causes inflow of gas towards the center at a rate of several solar masses per year, possibly along the spiral field seen in radio polarization and as optical dust lanes. This may solve the long-standing question of how to feed active nuclei, and explain the relation between the bolometric luminosity of AGN nuclei and the star-formation rate of their hosts. The strong magnetic fields generated in young galaxies may serve as the link between star formation and accretion onto supermassive black holes. -- Magnetic fields of >= 160 muG strength were measured in the central region of the almost edge-on starburst galaxy NGC 253. Four filaments emerging from the inner disk delineate the boundaries of the central outflow cone of hot gas. Strong Faraday rotation of the polarized emission from the background disk indicates a large-scale helical field in the outflow walls.Comment: 6 pages, 6 figures. To be published in 'The Central Kiloparsec in Galactic Nuclei - Astronomy at High Angular Resolution 2011', Journal of Physics Conf. Ser., IOP Publishin

Weighted Automata and Logics for Infinite Nested Words

Nested words introduced by Alur and Madhusudan are used to capture structures with both linear and hierarchical order, e.g. XML documents, without losing valuable closure properties. Furthermore, Alur and Madhusudan introduced automata and equivalent logics for both finite and infinite nested words, thus extending B\"uchi's theorem to nested words. Recently, average and discounted computations of weights in quantitative systems found much interest. Here, we will introduce and investigate weighted automata models and weighted MSO logics for infinite nested words. As weight structures we consider valuation monoids which incorporate average and discounted computations of weights as well as the classical semirings. We show that under suitable assumptions, two resp. three fragments of our weighted logics can be transformed into each other. Moreover, we show that the logic fragments have the same expressive power as weighted nested word automata.Comment: LATA 2014, 12 page

ALMA Observations of Quasar Host Galaxies at z ≃ 4.8

We present ALMA band-7 data of the [C ii] 157:74 m emission line and underlying far-infrared (FIR) continuum for twelve luminous quasars at z ' 4:8 powered by fast-growing supermassive black holes (SMBHs). Our total sample consists of eighteen quasars, twelve of which are presented here for the rst time. The new sources consists of six Herschel/SPIRE detected systems, which we de ne as "FIR-bright" sources, and six Herschel/SPIRE undetected systems, which we de ne as "FIR-faint" sources. We determine dust masses for the quasars hosts of Mdust 0:225:0 108M , implying ISM gas masses comparable to the dynamical masses derived from the [C ii] kinematics. It is found that on average the Mgii line is blueshifted by 500kms1 with respect to the [C ii] emission line, which is also observed when complementing our observations with data from the literature. We nd that all of our "FIR-bright" subsample and most of the "FIR-faint" objects lie above the main sequence of star forming galaxies at z 5. We detect companion sub-millimeter galaxies (SMGs) for two sources, both FIR-faint, with a range of projected distances of 20 60 kpc and with typical velocity shifts of j vj < 200kms1 from the quasar hosts. Of our total sample of eighteen quasars, 5/18 are found to have dust obscured starforming companions.ERC; STF