Gravitationally lensed QSOs in the ISSIS/WSO-UV era

Gravitationally lensed QSOs (GLQs) at redshift z = 1-2 play a key role in understanding the cosmic evolution of the innermost parts of active galaxies (black holes, accretion disks, coronas and internal jets), as well as the structure of galaxies at intermediate redshifts. With respect to studies of normal QSOs, GLQ programmes have several advantages. For example, a monitoring of GLQs may lead to unambiguous detections of intrinsic and extrinsic variations. Both kinds of variations can be used to discuss central engines in distant QSOs, and mass distributions and compositions of lensing galaxies. In this context, UV data are of particular interest, since they correspond to emissions from the immediate surroundings of the supermassive black hole. We describe some observation strategies to analyse optically bright GLQs at z of about 1.5, using ISSIS (CfS) on board World Space Observatory-Ultraviolet.Comment: 7 pages, 4 figures, Accepted for publication in Astrophysics & Space Scienc

Residual stress in laser cladded rail

To improve the fatigue life of components subject to loads with high surface strain gradients, it is possible to coat them with an alloy of higher durability. The present study focuses on the effect of cladding high value track components, made of a standard rail steel UIC 900A/grade 260, with a layer of a premium martensitic stainless steel to reduce wear and fatigue. The laser cladding process inevitably generates residual stresses in the clad and parent metal, which could be detrimental to the integrity of the component. Therefore, measurements to determine the residual stress state of cladded rail were performed using semi-destructive centre-hole and deep hole drilling and non-destructive neutron diffraction techniques. Subsequently, the effects of cycling loading and wear, representative of typical service loads, on the redistribution of the residual stress field were investigated. It was observed that laser cladding causes a triaxial compressive residual stress field in the clad and near the interface and a tensile stress field in the parent material. The stress field is shown to change when the first cycle of load is applied but reaches a steady state after only 10 cycles: After the 10th cycle there is no evidence that the clad continues accumulating strain which could indicate that there is low risk of ratcheting. Wear effect on residual stress redistribution was found to be local on the surface of the specimen only

Hubble Space Telescope observations of [O III] emission in nearby QSO2s : physical properties of the ionized outflows

We use Hubble Space Telescope/Space Telescope Imaging Spectrograph long-slit G430M and G750M spectra to analyse the extended [O iii] λ5007 emission in a sample of 12 nearby (z 1.6 × 1045 erg s−1) QSO2s. The purpose of the study is to determine the properties of the mass outflows of ionized gas and their role in active galactic nucleus feedback. We measure fluxes and velocities as functions of radial distances. Using cloudy models and ionizing luminosities derived from [O iii] λ5007, we are able to estimate the densities for the emission-line gas. From these results, we derive masses of [O iii]-emitting gas, mass outflow rates, kinetic energies, kinetic luminosities, momenta, and momentum flow rates as a function of radial distance for each of the targets. For the sample, masses are several times 103–107M⊙ and peak outflow rates are from 9.3 × 10−3 to 10.3M⊙yr−1. The peak kinetic luminosities are (3.4 × 10−8)–(4.9 × 10−4) of the bolometric luminosity, which does not approach the (5.0 × 10−3)–(5.0 × 10−2) range required by some models for efficient feedback. For Mrk 34, which has the largest kinetic luminosity of our sample, in order to produce efficient feedback there would have to be 10 times more [O iii]-emitting gas than that we detected at its position of maximum kinetic luminosity. Three targets show extended [O iii] emission, but compact outflow regions. This may be due to different mass profiles or different evolutionary histories

Quasars and their host galaxies

This review attempts to describe developments in the fields of quasar and quasar host galaxies in the past five. In this time period, the Sloan and 2dF quasar surveys have added several tens of thousands of quasars, with Sloan quasars being found to z>6. Obscured, or partially obscured quasars have begun to be found in significant numbers. Black hole mass estimates for quasars, and our confidence in them, have improved significantly, allowing a start on relating quasar properties such as radio jet power to fundamental parameters of the quasar such as black hole mass and accretion rate. Quasar host galaxy studies have allowed us to find and characterize the host galaxies of quasars to z>2. Despite these developments, many questions remain unresolved, in particular the origin of the close relationship between black hole mass and galaxy bulge mass/velocity dispersion seen in local galaxies.Comment: Review article, to appear in Astrophysics Update

The Fueling and Evolution of AGN: Internal and External Triggers

In this chapter, I review the fueling and evolution of active galactic nuclei (AGN) under the influence of internal and external triggers, namely intrinsic properties of host galaxies (morphological or Hubble type, color, presence of bars and other non-axisymmetric features, etc) and external factors such as environment and interactions. The most daunting challenge in fueling AGN is arguably the angular momentum problem as even matter located at a radius of a few hundred pc must lose more than 99.99 % of its specific angular momentum before it is fit for consumption by a BH. I review mass accretion rates, angular momentum requirements, the effectiveness of different fueling mechanisms, and the growth and mass density of black BHs at different epochs. I discuss connections between the nuclear and larger-scale properties of AGN, both locally and at intermediate redshifts, outlining some recent results from the GEMS and GOODS HST surveys.Comment: Invited Review Chapter to appear in LNP Volume on "AGN Physics on All Scales", Chapter 6, in press. 40 pages, 12 figures. Typo in Eq 5 correcte

Supermassive Binaries and Extragalactic Jets

Some quasars show Doppler shifted broad emission line peaks. I give new statistics of the occurrence of these peaks and show that, while the most spectacular cases are in quasars with strong radio jets inclined to the line of sight, they are also almost as common in radio-quiet quasars. Theories of the origin of the peaks are reviewed and it is argued that the displaced peaks are most likely produced by the supermassive binary model. The separations of the peaks in the 3C 390.3-type objects are consistent with orientation-dependent "unified models" of quasar activity. If the supermassive binary model is correct, all members of "the jet set" (astrophysical objects showing jets) could be binaries.Comment: 31 pages, PostScript, missing figure is in ApJ 464, L105 (see http://www.aas.org/ApJ/v464n2/5736/5736.html

Introducing the World Register of Introduced Marine Species (WRiMS)

Este artículo contiene 20 páginas, 1 figura, 4 tablas.A major historical challenge for the management of anthropogenic introductions of species has been the absence of a globally standardised system for species nomenclature. For over a decade, the World Register of Marine Species (WoRMS) has provided a taxonomically authoritative classification and designation of the currently accepted names for all known marine species. However, WoRMS mainly focuses on taxonomy and does not specifically address species introductions. Here, we introduce the World Register of Introduced Marine Species (WRiMS), a database directly linked to WoRMS that includes all introduced marine species, distinguishing native and introduced geographic ranges. Both the WoRMS and WRiMS contents are continually updated by specialists who add citations of original species descriptions, key taxonomic literature, images and notes on native and introduced geographic distributions. WRiMS editors take responsibility for assessing the validity of species records by critically evaluating if a species has been introduced to a region, erroneously identified and/or potentially naturally present in a region but previously unnoticed. WRiMS currently contains 2,714 introduced species. The amount and quality of the information entered depend on the availability of experts to update its contents. Because WRiMS is global and it combines species taxonomic and geographic information with links to other resources and expertise, it is currently the most comprehensive standardised database of marine introduced species. In addition, WRiMS forms the basis for a future global early warning system of marine species introductions.WRiMS came about through funding from the University of Auckland, Census of Marine Life’s OBIS funding, and EMODnet Biology (to Mark Costello), and LifeWatch Belgium (from VLIZ). We acknowledge the Research Foundation Flanders (FWO) who, as part of the Belgian contribution to LifeWatch, provided funding to organise the second WRiMS workshop held at VLIZ, in Oostende, Belgium, during the 23rd–25th of April 2018.Peer reviewe

High-tech composites to ancient metals

Neutron diffraction methods offer a direct measure of the elastic component of strain deep within crystalline materials through precise characterisation of the interplanar crystal lattice spacing. The unique non-destructive nature of this measurement technique is particularly beneficial in the context of engineering design and archaeological materials science, since it allows the evaluation of a variety of structural and deformational parameters inside real components without material removal, or at worst with minimal interference. We review a wide range of recent experimental studies using the Engin-X materials engineering instrument at the ISIS neutron source and show how the technique provides the basis for developing improved insight into materials of great importance to applications and industry. © 2009 Elsevier Ltd. All rights reserved