Search Results - "Carswell, R F"

Indications of a spatial variation of the fine structure constant by Webb, J K, King, J A, Murphy, M T, Flambaum, V V, Carswell, R F, Bainbridge, M B

“…We previously reported Keck telescope observations suggesting a smaller value of the fine structure constant α at high redshift. New Very Large Telescope (VLT)…”
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Measuring the fine-structure constant on a white dwarf surface; a detailed analysis of Fe v absorption in G191−B2B by Hu, J, Webb, J K, Ayres, T R, Bainbridge, M B, Barrow, J D, Barstow, M A, Berengut, J C, Carswell, R F, Dumont, V, Dzuba, V, Flambaum, V V, Lee, C C, Reindl, N, Preval, S P, Tchang-Brillet, W-Ü L

“…ABSTRACT The gravitational potential ϕ = GM/Rc2 at the surface of the white dwarf G191−B2B is 10 000 times stronger than that at the Earth’s surface. Numerous…”
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Metals in the z ∼ 3 intergalactic medium: results from an ultra-high signal-to-noise ratio UVES quasar spectrum by D'Odorico, V, Cristiani, S, Pomante, E, Carswell, R F, Viel, M, Barai, P, Becker, G D, Calura, F, Cupani, G, Fontanot, F, Haehnelt, M G, Kim, T-S, Miralda-Escude, J, Rorai, A, Tescari, E, Vanzella, E

“…In this work, we investigate the abundance and distribution of metals in the intergalactic medium (IGM) at ... through the analysis of an ultra-high…”
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Keck telescope constraint on cosmological variation of the proton-to-electron mass ratio by Malec, A. L., Buning, R., Murphy, M. T., Milutinovic, N., Ellison, S. L., Prochaska, J. X., Kaper, L., Tumlinson, J., Carswell, R. F., Ubachs, W.

“…Molecular transitions recently discovered at redshift zabs= 2.059 towards the bright background quasar J2123−0050 are analysed to limit cosmological variation…”
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Possible evidence for an inverted temperature–density relation in the intergalactic medium from the flux distribution of the Lyα forest by Bolton, J. S., Viel, M., Kim, T.-S., Haehnelt, M. G., Carswell, R. F.

“…We compare the improved measurement of the Lyα forest flux probability distribution at 1.7 < z < 3.2 presented by Kim et al. to a large set of hydrodynamical…”
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A cold component and the complex velocity structure of DLA1331 + 170 by Carswell, R. F., Jorgenson, R. A., Wolfe, A. M., Murphy, M. T.

“…We examine the velocity structure in the gas associated with H i in the damped Lyα absorption system at redshift z= 1.7764 towards the QSO 1331 + 170 using…”
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The power spectrum of the flux distribution in the Lyman α forest of a large sample of UVES QSO absorption spectra (LUQAS) by Kim, T.-S., Viel, M., Haehnelt, M. G., Carswell, R. F., Cristiani, S.

“…The flux power spectra of the Lyman α forest from a sample of 27 quasi-stellar objects (QSOs) taken with the high-resolution Ultraviolet Echelle Spectrograph…”
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High-precision limit on variation in the fine-structure constant from a single quasar absorption system by Kotu, S M, Murphy, M T, Carswell, R F

“…The brightest southern quasar above redshift z = 1, HE 0515-4414, with its strong intervening metal absorption line system at z^sub abs^ = 1.1508, provides a…”
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A precise deuterium abundance: remeasurement of the z = 3.572 absorption system towards the quasar PKS1937–101 by Riemer-Sørensen, S., Kotuš, S., Webb, J. K., Ali, K., Dumont, V., Murphy, M. T., Carswell, R. F.

“…Abstract The primordial deuterium abundance probes fundamental physics during the big bang nucleosynthesis and can be used to infer cosmological parameters…”
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Artificial intelligence and quasar absorption system modelling; application to fundamental constants at high redshift by Lee, Chung-Chi, Webb, John K, Carswell, R F, Milaković, Dinko

“…ABSTRACT We have developed a new fully automated Artificial Intelligence (AI)-based method for deriving optimal models of complex absorption systems. The AI…”
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The physical properties of the Lyα forest at z > 1.5 by Kim, T.-S., Carswell, R. F., Cristiani, S., D'Odorico, S., Giallongo, E.

“…Combining a new, increased data set of eight quasi-stellar objects (QSOs) covering the Lyα forest at redshifts 1.5 < z < 3.6 from VLT/UVES observations with…”
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Quantum mechanics at high redshift – Modelling Damped Lyman–α absorption systems by Lee, C C, Webb, J K, Carswell, R F

“…Abstract For around 100 years, hydrogen spectral modelling has been based on Voigt profile fitting. The semi-classical Voigt profile is based on a 2-level atom…”
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The evolution of the low-density H i intergalactic medium from z = 3.6 to 0: data, transmitted flux, and H i column density by Kim, T-S, Wakker, B P, Nasir, F, Carswell, R F, Savage, B D, Bolton, J S, Fox, A J, Viel, M, Haehnelt, M G, Charlton, J C, Rosenwasser, B E

“…ABSTRACT We present a new, uniform analysis of the H i transmitted flux (F) and H i column density ($N_{\mathrm{H\,{\small I}}}$) distribution in the…”
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The effect of (strong) discrete absorption systems on the Lyman α forest flux power spectrum by Viel, M., Haehnelt, M. G., Carswell, R. F., Kim, T.-S.

“…We demonstrate that the Lyman α forest flux power spectrum of ‘randomized’ quasi-stellar object (QSO) absorption spectra is comparable in shape and amplitude…”
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Exploring the thermal state of the low-density intergalactic medium at z = 3 with an ultrahigh signal-to-noise QSO spectrum by Rorai, A., Becker, G. D., Haehnelt, M. G., Carswell, R. F., Bolton, J. S., Cristiani, S., D'Odorico, V., Cupani, G., Barai, P., Calura, F., Kim, T.-S., Pomante, E., Tescari, E., Viel, M.

“…Abstract At low densities, the standard ionization history of the intergalactic medium (IGM) predicts a decreasing temperature of the IGM with decreasing…”
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A high deuterium abundance at redshift z = 0.7 by Lanzetta, K. M, Webb, J. K, Carswell, R. F, Ferlet, R, Lemoine, M, Vidal-Madjar, A, Bowen, D. V

“…Of the light elements, the primordial abundance of deuterium relative to hydrogen, (D/H)p, provides the most sensitive diagnostic for the cosmological mass…”
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Evidence of bimodal physical properties of intervening, optically thin C iii absorbers at z ∼ 2.5 by Kim, T.-S., Carswell, R. F., Ranquist, D.

“…We present the Voigt profile analysis of 132 intervening C iv+C iii components associated with optically thin H i absorbers at 2.1 < z < 3.4 in the 19…”
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Cosmological evolution of heavy-element and H2 abundances by Curran, S. J., Webb, J. K., Murphy, M. T., Carswell, R. F.

“…ABSTRACT Spectroscopic observations of distant quasars have resulted in the detection of molecular hydrogen in intervening damped Lyman α absorption clouds…”
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A large population of metal-rich, compact, intergalactic C iv absorbers – evidence for poor small-scale metal mixing by Schaye, Joop, Carswell, Robert F., Kim, Tae-Sun

“…We carried out a survey for high-metallicity C iv absorbers at redshift z≈ 2.3 in nine high-quality quasar spectra. Using a novel analysis technique, based on…”
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Evidence for structure in the H I column density distribution of QSO absorbers by Petitjean, P., Webb, J. K., Rauch, M., Carswell, R. F., Lanzetta, K.

“…The H I column density distribution function of QSO absorption line systems is investigated using recent data with high spectral resolution, and extensive…”
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