The discovery of a type II quasar at z= 1.65 with integral-field spectroscopy

In this Letter we report the serendipitous discovery of a genuine type II quasar at z= 1.65 using integral-field data from the Visual Multi-Object Spectrograph (VIMOS) on the Very Large Telescope (VLT). This is the first discovery of a type II quasar at z > 1 from optical data alone. J094531-242831, hereafter J0945-2428, exhibits strong narrow (v < 1500 km s-1) emission lines, has a resolved host galaxy, and is undetected to a radio flux density limit of S5 GHz= 0.15 mJy (3σ) . All of these characteristics lead us to believe that J0945-2428 is a bona fide type II quasar. The luminosity of the narrow emission lines in this object suggest that the intrinsic power of the central engine is similar to that found in powerful radio galaxies, indicative of a similarly large supermassive black hole of ∼ 3 × 108 M⊙ (assuming that it is accreting at its Eddington limit). However, from near-infrared imaging observations we find that the old stellar population in the host galaxy has a luminosity of ∼ 0.2 L⋆, mildly inconsistent with the correlation between black hole mass and bulge luminosity found locally, although the uncertainty in the black hole mass estimate is large. This discovery highlights the power that integral-field units have in discovering hidden populations of objects, particularly the sought-after type II quasars, which are invoked to explain the hard X-ray background. As such, future large integral-field surveys could open up a new window on the obscured accretion activity in the Universe

A complete distribution of redshifts for sub-millimetre galaxies in the SCUBA-2 Cosmology Legacy Survey UDS field

This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. Available online at https://doi.org/10.1093/mnras/stx1689. © 2017 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.Sub-milllimetre galaxies (SMGs) are some of the most luminous star-forming galaxies in the Universe, however their properties remain hard to determine due to the difficulty of identifying their optical\slash near-infrared counterparts. One of the key steps to determining the nature of SMGs is measuring a redshift distribution representative of the whole population. We do this by applying statistical techniques to a sample of 761 850$\mu$m sources from the SCUBA-2 Cosmology Legacy Survey observations of the UKIDSS Ultra-Deep Survey (UDS) Field. We detect excess galaxies around $> 98.4$ per cent of the 850$\mu$m positions in the deep UDS catalogue, giving us the first 850$\mu$m selected sample to have virtually complete optical\slash near-infrared redshift information. Under the reasonable assumption that the redshifts of the excess galaxies are representative of the SMGs themselves, we derive a median SMG redshift of $z = 2.05 \pm 0.03$, with 68 per cent of SMGs residing between $1.07Peer reviewedFinal Accepted Versio

Integral-field studies of the high-redshift Universe

We present results from a new method of exploring the distant Universe. We use 3-D spectroscopy to sample a large cosmological volume at a time when the Universe was less than 3 billion years old to investigate the evolution of star-formation activity. Within this study we also discovered a high redshift type-II quasar which would not have been identified with imaging studies alone. This highlights the crucial role that integral-field spectroscopy may play in surveying the distant Universe in the future.Comment: From proceedings of Euro3D Spectroscopy annual RTN network meeting (ed. J. Walsh). 5 pages, accepted for publication in Astron. Nach

Possible High-Redshift, Low-Luminosity AGN Activity in the Hubble Deep Field

In the Hubble Deep Field (HDF), twelve candidate sources of high-redshift (z > 3.5) AGN activity have been identified. The color selection criteria were established by passing spectra of selected quasars and Seyfert galaxies (appropriately redshifted and modified for "Lyman forest" absorption), as well as stars, observed normal and starburst galaxies, and galaxy models for various redshifts through the filters used for the HDF observations. The actual identification of AGN candidates also involved convolving a Laplacian-of-Gaussian filter with the HDF images, thereby removing relatively flat galactic backgrounds and leaving only the point-like components in the centers. Along with positions and colors, estimated redshifts and absolute magnitudes are reported, with the candidates falling toward the faint end of the AGN luminosity function. One candidate has been previously observed spectroscopically, with a measured redshift of 4.02. The number of sources reported here is consistent with a simple extrapolation of the observed quasar luminosity function to magnitude 30 in B_Johnson. Implications for ionization of the intergalactic medium and for gravitational lensing are discussed.Comment: 10 pages LaTex plus 2 separate files (Table 1 which is a two-page landscape LaTex file; and Figure 6 which is a large (0.7 MB) non-encapsulated postscript file). Accepted for publication in the Astronomical Journa

Ground and flight test experience with a triple redundant digital fly by wire control system

A triplex digital fly by wire flight control system was developed and installed in an F-8C aircraft to provide fail operative, full authority control. Hardware and software redundancy management techniques were designed to detect and identify failures in the system. Control functions typical of those projected for future actively controlled vehicles were implemented

Assessing smoking status in children, adolescents and adults: cotinine cut-points revisited

Aims To reassess saliva cotinine cut-points to discriminate smoking status. Cotinine cut-points that are in use were derived from relatively small samples of smokers and non-smokers 20 or more years ago. It is possible that optimal cut-points may have changed as prevalence and exposure to passive smoking have declined. Design Cross-sectional survey of the general population, with assessment of self-reported smoking and saliva cotinine. Participants A total of 58 791 respondents aged 4 years and older in the Health Survey for England for the years 1996-2004 who provided valid saliva cotinine specimens. Measures Saliva cotinine concentrations, demographic variables, self-reported smoking, presence or absence of smoking in the home, a composite index of social disadvantage derived from occupation, housing tenure and access to a car. Findigns A cut-point of 12 ng/ml performed best overall, with specificity of 96.9% and sensitivity of 96.7% in discriminating confirmed cigarette smokers from never regular smokers. This cut-point also identified correctly 95.8% of children aged 8-15 years smoking six or more cigarettes a week. There was evidence of substantial misreport in claimed ex-smokers, especially adolescents (specificity 72.3%) and young adults aged 16-24 years (77.5%). Optimal cut-points varied by presence (18 ng/ml) or absence (5 ng/ml) of smoking in the home, and there was a gradient from 8 ng/ml to 18 ng/ml with increasing social disadvantage. Conclusions The extent of non-smokers' exposure to other people's tobacco smoke is the principal factor driving optimal cotinine cut-points. A cut-point of 12 ng/ml can be recommended for general use across the whole age range, although different cut-points may be appropriate for population subgroups and in societies with differing levels of exposure to secondhand smoke

Resource acquisition, distribution and end-use efficiencies and the growth of industrial society

A key feature of the growth of industrial society is the acquisition of increasing quantities of resources from the environment and their distribution for end use. With respect to energy, growth has been near exponential for the last 160 years. We attempt to show that the global distribution of resources that underpins this growth may be facilitated by the continual development and expansion of near optimal directed networks. If so, the distribution efficiencies of these networks must decline as they expand due to path lengths becoming longer and more tortuous. To maintain long-term exponential growth the physical limits placed on the distribution networks appear to be counteracted by innovations deployed elsewhere in the system: namely at the points of acquisition and end use. We postulate that the maintenance of growth at the specific rate of ~2.4% yr−1 stems from an implicit desire to optimise patterns of energy use over human working lifetimes

The environment and host haloes of the brightest z~6 Lyman-break galaxies

By studying the large-scale structure of the bright high-redshift Lyman-break galaxy (LBG) population it is possible to gain an insight into the role of environment in galaxy formation physics in the early Universe. We measure the clustering of a sample of bright (-22.7<M_UV<-21.125) LBGs at z~6 and use a halo occupation distribution (HOD) model to measure their typical halo masses. We find that the clustering amplitude and corresponding HOD fits suggests that these sources are highly biased (b~8) objects in the densest regions of the high-redshift Universe. Coupled with the observed rapid evolution of the number density of these objects, our results suggest that the shape of high luminosity end of the luminosity function is related to feedback processes or dust obscuration in the early Universe - as opposed to a scenario where these sources are predominantly rare instances of the much more numerous M_UV ~ -19 population of galaxies caught in a particularly vigorous period of star formation. There is a slight tension between the number densities and clustering measurements, which we interpret this as a signal that a refinement of the model halo bias relation at high redshifts or the incorporation of quasi-linear effects may be needed for future attempts at modelling the clustering and number counts. Finally, the difference in number density between the fields (UltraVISTA has a surface density ~1.8 times greater than UDS) is shown to be consistent with the cosmic variance implied by the clustering measurements.Comment: 19 pages, 8 figures, accepted MNRAS 23rd March 201

Transportation noise pollution - Control and abatement

Control and abatement of transportation noise pollutio

Using the split squat to potentiate bilateral and unilateral jump performance

The purpose of this study was to examine if a split squat conditioning exercise with no or light loads could potentiate unilateral and bilateral jump performance. Twelve semi-professional rugby players (age: 22.3 +/- 1.4 years; height: 1.84 +/- 0.05 m, mass: 92.4 +/- 9.6 kg) from the English National League 1 performed a series of unilateral and bilateral countermovement jumps (CMJ) and broad jumps (BJ) over the course of two testing days. Both testing days involved performing baseline jumps before completing two sets of ten repetitions of a split squat, this completed with either bodyweight (testing session 1) or a 30kg weighted vest (testing session 2). A five-minute recovery period was permitted both following the warm up and following the completion of the split squat exercise. Significantly larger bilateral jump scores were reported following completion of the bodyweight split squat: CMJ (p = 0.001, ES = 0.44, [mean difference 2.517]), BJ (p = 0.001, ES = 0.37, [mean difference 3.817]), and the weighted vest split squat; CMJ (p = 0.001, ES = 0.8, [mean difference 4.383]), BJ (p = 0.001, ES = 0.68, [mean difference 6.817]). The findings of this study demonstrate that no or light loads of a split squat conditioning exercise are able to potentiate bilateral jump performance in semi-professional rugby players without the need for expensive weight room equipment. As such, this may provide coaches with a viable option of enhancing bilateral jump performance as part of a warm up or on-field conditioning practice