Zobrazeno 1 - 10
of 121
pro vyhledávání: '"Robert F. Carswell"'
Publikováno v:
Monthly Notices of the Royal Astronomical Society. 508:3620-3633
This paper describes the optimisation theory on which VPFIT, a non-linear least-squares program for modelling absorption spectra, is based. Particular attention is paid to precision. Voigt function derivatives have previously been calculated using nu
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::05595dbfee2fa7f9d02f63b380dc3489
https://doi.org/10.1093/mnras/stab2895
https://doi.org/10.1093/mnras/stab2895
Publikováno v:
Monthly Notices of the Royal Astronomical Society. 507:27-42
High resolution spectra of quasar absorption systems provide the best constraints on temporal or spatial changes of fundamental constants in the early universe. An important systematic that has never before been quantified concerns model non-uniquene
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::0e6a90d23e6b281c160f406a0fc5c9e2
https://doi.org/10.1093/mnras/stab2005
https://doi.org/10.1093/mnras/stab2005
Publikováno v:
Monthly Notices of the Royal Astronomical Society. 504:1787-1800
Exploring the possibility that fundamental constants of Nature might vary temporally or spatially constitutes one of the key science drivers for the European Southern Observatory's ESPRESSO spectrograph on the VLT and for the HIRES spectrograph on th
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::b86d7a2d43b08efb87880ff0371e9a03
https://doi.org/10.1093/mnras/stab977
https://doi.org/10.1093/mnras/stab977
Publikováno v:
Monthly Notices of the Royal Astronomical Society. 501:2268-2278
Robust model-fitting to spectroscopic transitions is a requirement across many fields of science. The corrected Akaike and Bayesian information criteria (AICc and BIC) are most frequently used to select the optimal number of fitting parameters. In ge
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::0f2b7a66a207d510922c9232f539f4a9
https://doi.org/10.1093/mnras/staa3551
https://doi.org/10.1093/mnras/staa3551
Autor:
John K. Webb, Luca Pasquini, Paolo Molaro, Chung-Chi Lee, Robert F. Carswell, Dinko Milaković
Publikováno v:
Monthly Notices of the Royal Astronomical Society. 500:1-21
New observations of the quasar HE0515$-$4414 have been made using the HARPS spectrograph on the ESO 3.6m telescope, aided by the Laser Frequency Comb (LFC). We present three important advances for $\alpha$ measurements in quasar absorption spectra fr
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::36cec910d251de735cc2f80214d3fe57
https://doi.org/10.1093/mnras/staa3217
https://doi.org/10.1093/mnras/staa3217
Autor:
Chung-Chi Lee, John K Webb, Robert F Carswell, Vladimir A Dzuba, Victor V Flambaum, Dinko Milaković
The high resolution spectrograph ESPRESSO on the VLT allows measurements of fundamental constants at unprecedented precision and hence enables tests for spacetime variations predicted by some theories. In a series of recent papers, we developed optim
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::5cc5d28f47d466537f8561875e06cb8f
Autor:
Sarah E. I. Bosman, Luca Pasquini, Chung-Chi Lee, Paolo Molaro, Jochen Liske, Mariusz P. Dąbrowski, Katarzyna Leszczynska, Konrad Marosek, Robert F. Carswell, Matthew Bainbridge, Carlos Martins, Dinko Milaković, John K. Webb, A. C. O. Leite, Vincent Dumont, Michael R. Wilczynska, John D. Barrow
Publikováno v:
Science Advances
Observations of the redshift z=7.085 quasar J1120+0641 have been used to search for variations of the fine structure constant, alpha, over the redshift range 5.5 to 7.1. Observations at z=7.1 probe the physics of the universe when it was only 0.8 bil
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::0a46f7a208227471a8c8aaa5da92031f
https://doi.org/10.1126/sciadv.aay9672
https://doi.org/10.1126/sciadv.aay9672
Autor:
Robert F. Carswell, Laura C. Keating, Alberto Rorai, James S. Bolton, Prakash Gaikwad, Ewald Puchwein, Fakhri S. Zahedy, Elisa Boera, Vid Iršič, George D. Becker, Hsiao-Wen Chen, Girish Kulkarni, Jonathan Chardin, Michael Rauch, Martin G. Haehnelt, Eduardo Bañados
Publikováno v:
Mon.Not.Roy.Astron.Soc.
Mon.Not.Roy.Astron.Soc., 2020, 494 (4), pp.5091-5109. ⟨10.1093/mnras/staa907⟩
Mon.Not.Roy.Astron.Soc., 2020, 494 (4), pp.5091-5109. ⟨10.1093/mnras/staa907⟩
We compare a sample of five high-resolution, high S/N Ly$\alpha$ forest spectra of bright $65$ with those obtained from mock absorption spectra from the Sherwood and Sherwood-Relics suites of hydrodynamical simulations of the intergalactic medium (IG
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e78c31af6e11ac115ee2a8fac72912be
https://hal.archives-ouvertes.fr/hal-02483886
https://hal.archives-ouvertes.fr/hal-02483886
Autor:
Benjamin Rosenwasser, Andrew J. Fox, Fahad Nasir, Blair D. Savage, Robert F. Carswell, Martin G. Haehnelt, Bart P. Wakker, T. S. Kim, Jane C. Charlton, James S. Bolton, Matteo Viel
We present a new, uniform analysis of the HI transmitted flux (F) and HI column density (N(HI)) distribution in the low-density IGM as a function of redshift z for 0
Comment: 24 pages, 17 figures, 8 tables, accepted for publication to MNRAS, 5 s
Comment: 24 pages, 17 figures, 8 tables, accepted for publication to MNRAS, 5 s
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::025f5e1b31ab22ca8439fd141a784d72
Publikováno v:
Monthly Notices of the Royal Astronomical Society.
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 approximation. Whilst the Voigt profile is excellent for many circumstances, the accuracy is insuff
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::10eb192fe8aee23e620f17064d93df59
https://doi.org/10.1093/mnras/stz3170
https://doi.org/10.1093/mnras/stz3170