84 research outputs found
The rate of extreme coronal line emitters in the Baryon Oscillation Spectroscopic Survey LOWZ sample
No full textJ. Callow et al.Extreme coronal line emitters (ECLEs) are a rare class of galaxy that exhibit strong, high-ionization iron coronal emission lines in their spectra. In some cases, these lines are transient and may be the result of tidal disruption event (TDEs). To test this connection, we calculate the rate of variable ECLEs (vECLEs) at redshift. We search for ECLEs in the Baryon Oscillation Spectroscopic Survey (BOSS) LOWZ sample and discover two candidate ECLEs. Using follow-up spectra from the Dark Energy Spectroscopic Instrument and Gemini Multi-Object Spectrograph, and mid-infrared observations from the Wide-field Infrared Survey Explorer, we determine that one of these galaxies is a vECLE. Using this galaxy, we calculate the galaxy-normalized vECLE rate at redshift to be and the mass-normalized rate to be. This is then converted to a volumetric rate of. Formally, the LOWZ vECLE rates are times lower than the rates calculated from the Sloan Digital Sky Survey Legacy sample at redshift. However, given the large uncertainties on both measurements, they are consistent with each other at. Both the galaxy-normalized and volumetric rates are one to two orders of magnitude lower than TDE rates from the literature, consistent with vECLEs being caused by per cent of all TDEs.This work was supported by the Science and Technology Facilities Council [grants ST/S000550/1 and ST/W001225/1]. Funding for the Sloan Digital Sky Survey (SDSS) and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, and the Max Planck Society, and the Higher Education Funding Council for England. The SDSS Website is http://www.sdss.org/. The SDSS is managed by the Astrophysical Research Consortium (ARC) for the Participating Institutions. The Participating Institutions are the American Museum of Natural History, Astrophysical Institute Potsdam, University of Basel, University of Cambridge, Case Western Reserve University, The University of Chicago, Drexel University, Fermilab, the Institute for Advanced Study, the Japan Participation Group, The Johns Hopkins University, the Joint Institute for Nuclear Astrophysics, the Kavli Institute for Particle Astrophysics and Cosmology, the Korean Scientist Group, the Chinese Academy of Sciences (LAMOST), Los Alamos National Laboratory, the Max-Planck-Institute for Astronomy (MPIA), the Max-Planck-Institute for Astrophysics (MPA), New Mexico State University, Ohio State University, University of Pittsburgh, University of Portsmouth, Princeton University, the United States Naval Observatory, and the University of Washington. This material is based upon work supported by the U.S. Department of Energy (DOE), Office of Science, Office of High-Energy Physics, under Contract no. DE-AC02-05CH11231, and by the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility under the same contract. Additional support for DESI was provided by the U.S. National Science Foundation (NSF), Division of Astronomical Sciences under Contract No. AST-0950945 to the NSF’s National Optical-Infrared Astronomy Research Laboratory; the Science and Technology Facilities Council of the United Kingdom; the Gordon and Betty Moore Foundation; the Heising–Simons Foundation; the French Alternative Energies and Atomic Energy Commission (CEA); the National Council of Humanities, Science and Technology of Mexico (CONAHCYT); the Ministry of Science, Innovation and Universities of Spain (MICIU/AEI/10.13039/501100011033), and by the DESI Member Institutions: https://www.desi.lbl.gov/collaborating-institutions. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the U. S. National Science Foundation, the U. S. Department of Energy, or any of the listed funding agencies. This research has made use of NASA’s Astrophysics Data System Bibliographic Services and the NASA/IPAC Infrared Science Archive, which is funded by the National Aeronautics and Space Administration (NASA) and operated by the California Institute of Technology. This publication also makes use of data products from NEOWISE, which is a project of the Jet Propulsion Laboratory/California Institute of Technology, funded by the Planetary Science Division of NASA. The CRTS survey is supported by the U.S. National Science Foundation (NSF) under grants AST-0909182 and AST-1313422.Peer reviewe
Potential utilisation of organic waste in concrete at OT mine: Project Progress Report – Phase 1
No full textThis project investigated the feasibility of using wastewater treatment plant sludge to supplement concrete mixtures to reduce the overall amount of cement used in the concrete mixture. The amended concrete mixture is intended to lower the carbon footprint, reduce operational costs, save water, and minimise environmental impacts of the disposal of the treated waste.
The first phase of the project was dedicated to determining the characteristics of typical wastewater sludge, undertaking initial concrete preparation with different sludge ratios and the analysis of the prepared concrete for its leaching potential and odour release
Potential Utilisation of Organic Waste in Concrete at OT Mine: Exploring Mechanical Properties of Amended Concrete (Phase 2)
No full textThis project investigated mechanical properties of amended shotcrete mixture using waste materials including compressive strength, tensile strength and other key parameters as well as leaching potential of the mixture as a function of time
Geophysical early warning of salt precipitation during geological carbon sequestration
No full textSequestration of industrial carbon dioxide (CO2) in deep geological saline aquifers is needed to mitigate global greenhouse gas emissions; monitoring the mechanical integrity of reservoir formations is essential for effective and safe operations. Clogging of fluid transport pathways in rocks from CO2-induced salt precipitation reduces injectivity and potentially compromises the reservoir storage integrity through pore fluid pressure build-up. Here, we show that early warning of salt precipitation can be achieved through geophysical remote sensing. From elastic P- and S-wave velocity and electrical resistivity monitoring during controlled laboratory CO2 injection experiments into brine-saturated quartz-sandstone of high porosity (29%) and permeability (1660 mD), and X-ray CT imaging of pore-scale salt precipitation, we were able to observe, for the first time, how CO2-induced salt precipitation leads to detectable geophysical signatures. We inferred salt-induced rock changes from (i) strain changes, (ii) a permanent ~ 1.5% decrease in wave velocities, linking the geophysical signatures to salt volume fraction through geophysical models, and (iii) increases of porosity (by ~ 6%) and permeability (~ 7%). Despite over 10% salt saturation, no clogging effects were observed, which suggests salt precipitation could extend to large sub-surface regions without loss of CO2 injectivity into high porosity and permeability saline sandstone aquifers
Welcome home to 'Smithy' of the air [music] : (song-dance) /
No full textD11 (Publisher number). For voice and piano.; Caption title.; Cover bears port. of Smithy.; Cover bears ill. by Ian Porter.; Pl. no.: D11.; Also available online http://nla.gov.au/nla.mus-vn5465277; 1930 in Australia, Great Britain and throughout by Basil C.W. Dean, Song Writer & Publisher, State Theatre Block, Sydney, Australia.; From the collection of Keith Watson. ANL
The rate of extreme coronal line emitting galaxies in the Sloan Digital Sky Survey and their relation to tidal disruption events
No full textThe data underlying this article are available in the article and in its online supplementary material through Zenodo at Callow et al. (2024). The reduced data and derived measurements in this article will be shared on reasonable request to the corresponding author.J. Callow et al.High-ionization iron coronal lines (CLs) are a rare phenomenon observed in galaxy and quasi-stellar object spectra that are thought to be created by high-energy emission from active galactic nuclei and certain types of transients. In cases known as extreme coronal line emitting galaxies (ECLEs), these CLs are strong and fade away on a time-scale of years. The most likely progenitors of these variable CLs are tidal disruption events (TDEs), which produce sufficient high-energy emission to create and sustain the CLs over these time-scales. To test the possible connection between ECLEs and TDEs, we present the most complete variable ECLE rate calculation to date and compare the results to TDE rates from the literature. To achieve this, we search for ECLEs in the Sloan Digital Sky Survey (SDSS). We detect sufficiently strong CLs in 16 galaxies, more than doubling the number previously found in SDSS. Using follow-up spectra from the Dark Energy Spectroscopic Instrument and Gemini Multi-Object Spectrograph, Wide-field Infrared Survey Explorer mid-infrared observations, and Liverpool Telescope optical photometry, we find that none of the nine new ECLEs evolve in a manner consistent with that of the five previously discovered variable ECLEs. Using this sample of five variable ECLEs, we calculate the galaxy-normalized rate of variable ECLEs in SDSS to be RG = 3.6 +2.6 −1.8 (statistical) +5.1 −0.0 (systematic) × 10−6 galaxy−1 yr−1. The mass-normalized rate is RM = 3.1 +2.3 −1.5 (statistical) +4.4 −0.0 (systematic) × 10−17 M−1 yr−1 and the volumetric rate is RV = 7 +20 −5 (statistical) +10 −0.0 (systematic) × 10−9 Mpc−3 yr−1. Our rates are one to two orders of magnitude lower than TDE rates from the literature, which suggests that only 10–40 per cent of all TDEs produce variable ECLEs. Additional uncertainties in the rates arising from the structure of the interstellar medium have yet to be included.This work was supported by the Science & Technology Facilities Council (grants ST/S000550/1 and ST/W001225/1).
Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, and the Max Planck Society, and the Higher Education Funding Council for England. The SDSS Website is http://www.sdss.org/.
The SDSS is managed by the Astrophysical Research Consortium (ARC) for the Participating Institutions. The Participating Institutions are the American Museum of Natural History, Astrophysical Institute Potsdam, University of Basel, University of Cambridge, Case Western Reserve University, The University of Chicago, Drexel University, Fermilab, the Institute for Advanced Study, the Japan Participation Group, The Johns Hopkins University, the Joint Institute for Nuclear Astrophysics, the Kavli Institute for Particle Astrophysics and Cosmology, the Korean Scientist Group, the Chinese Academy of Sciences (LAMOST), Los Alamos National Laboratory, the Max-Planck-Institute for Astronomy (MPIA), the Max-Planck-Institute for Astrophysics (MPA), New Mexico State University, Ohio State University, University of Pittsburgh, University of Portsmouth, Princeton University, the United States Naval Observatory, and the University of Washington.
This material is based upon work supported by the U.S. Department of Energy (DOE), Office of Science, Office of High-Energy Physics, under Contract No. DE-AC02-05CH11231, and by the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility under the same contract. Additional support for DESI was provided by the U.S. National Science Foundation (NSF), Division of Astronomical Sciences under Contract No. AST-0950945 to the NSF’s National Optical-Infrared Astronomy Research Laboratory; the Science and Technology Facilities Council of the United Kingdom; the Gordon and Betty Moore Foundation; the Heising-Simons Foundation; the French Alternative Energies and Atomic Energy Commission (CEA); the National Council of Science and Technology of Mexico (CONACYT); the Ministry of Science and Innovation of Spain (MICINN), and by the DESI Member Institutions: https://www.desi.lbl.gov/collaborating-institutions. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the U.S. National Science Foundation, the U.S. Department of Energy, or any of the listed funding agencies.
The authors are honoured to be permitted to conduct scientific research on Iolkam Du’ag (Kitt Peak), a mountain with particular significance to the Tohono O’odham Nation.
This research has made use of NASA’s Astrophysics Data System Bibliographic Services and the NASA/IPAC Infrared Science Archive, which is funded by the National Aeronautics and Space Administration (NASA) and operated by the California Institute of Technology. This publication also makes use of data products from NEOWISE, which is a project of the Jet Propulsion Laboratory/California Institute of Technology, funded by the Planetary Science Division of NASA. The CRTS survey is supported by the U.S. National Science Foundation (NSF) under grants AST-0909182 and AST-1313422.
Based on observations obtained at the international Gemini Observatory, a programme of NSF’s NOIRLab, processed using dragons (Data Reduction for Astronomy from Gemini Observatory North and South), which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation on behalf of the Gemini Observatory partnership: the National Science Foundation (United States), National Research Council (Canada), Agencia Nacional de Investigación y Desarrollo (Chile), Ministerio de Ciencia, Tecnología e Innovación (Argentina), Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). This work was enabled by observations made from the Gemini North telescope, located within the Maunakea Science Reserve and adjacent to the summit of Maunakea. We are grateful for the privilege of observing the Universe from a place that is unique in both its astronomical quality and its cultural significance.Peer reviewe
Extending Relational Model Transformations to Better Support the Verification of Increasingly Autonomous Systems
No full textExtending relational model transformations to better support the verification of increasingly autonomous systems This item was submitted to Loughborough University’s Institutional Repository by the/an author. Additional Information: • A dissertation thesis submitted in partial fulfilment of the requirements fo
Specificity in the settlement - modifying response of bacterial biofilms towards zoospores of the marine alga Enteromorpha
No full textPrevious studies have shown that the rate of settlement of zoospores of the green alga Enteromorpha is stimulated by mixed microbial biofilms and that the number of zoospores settling is positively correlated with the number of bacteria in the biofilm. In the present study the specificity of this relationship has been investigated. Ninety-nine strains of marine bacteria were isolated from natural biofilms on rocks and the surface of Enteromorpha plants. Isolates were screened by denaturing gradient gel electrophoresis (DGGE) to eliminate replicates and 16S rDNA sequencing identified a total of 37 unique strains. Phylogenetic analysis revealed that the isolated bacterial strains belonged to three groups gamma-Proteobacteria (28 strains), Cytophaga-Flavobacteria-Bacteroid (CFB) group (six strains) and alpha-Proteobacteria (one strain). Two strains were unassigned, showing <93% sequence similarity with the CFB group. The main genera of gamma-Proteobacteria were Pseudoalteromonas (14 strains), Vibrio (five strains), Shewanella (five strains), Halomonas (three strains) and Pseudomonas (one strain). Spore settlement experiments were conducted on single-species biofilms, developed for different times on glass slides. The effect of correcting spore settlement values for biofilm density was evaluated. Results showed that the effect of bacterial strains on spore settlement was strain- but not taxon-specific and activity varied with the age of the biofilm. However, most of the strains belonging to genera Vibrio and Shewanella showed stimulation. Pseudoalteromonas strains showed a range of effects including settlement-inhibiting, paralysing and lysing activities. Spatial analysis of bacterial density in the presence and absence of spores revealed a range of different types of association between spores and bacteria. Overall, the spatial association between spores and bacteria appears to be independent of the overall quantitative influence of bacterial cells on spore settlement
Is there a symbiotic relationship between periphytic bacteria and the green alga Ulva (syn. Enteromorpha)?
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