11 results on '"Ryan J. Cooke"'
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2. PypeIt: The Python Spectroscopic Data Reduction Pipeline.
- Author
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J. Xavier Prochaska, Joseph F. Hennawi, Kyle B. Westfall, Ryan J. Cooke, Feige Wang, Tiffany Hsyu, Frederick B. Davies, Emanuele Paolo Farina, and Debora Pelliccia
- Published
- 2020
- Full Text
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3. Primordial helium-3 redux: The helium isotope ratio of the Orion nebula
- Author
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Ryan J. Cooke, Pasquier Noterdaeme, James W. Johnson, Max Pettini, Louise Welsh, Celine Peroux, Michael T. Murphy, David H. Weinberg, Cooke, Ryan J [0000-0001-7653-5827], Noterdaeme, Pasquier [0000-0002-5777-1629], Johnson, James W [0000-0002-6534-8783], Pettini, Max [0000-0002-5139-4359], Welsh, Louise [0000-0002-0786-7307], Peroux, Celine [0000-0002-4288-599X], Murphy, Michael T [0000-0002-7040-5498], Weinberg, David H [0000-0001-7775-7261], Apollo - University of Cambridge Repository, Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), and Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Galaxies and Cosmology ,Astrophysics - Astrophysics of Galaxies ,Space and Planetary Science ,TheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITY ,Astrophysics of Galaxies (astro-ph.GA) ,Astrophysics::Solar and Stellar Astrophysics ,5106 Nuclear and Plasma Physics ,Astrophysics::Earth and Planetary Astrophysics ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] ,51 Physical Sciences ,Astrophysics::Galaxy Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We report the first direct measurement of the helium isotope ratio, 3He/4He, outside of the Local Interstellar Cloud, as part of science verification observations with the upgraded CRyogenic InfraRed Echelle Spectrograph (CRIRES). Our determination of 3He/4He is based on metastable HeI* absorption along the line-of-sight towards Tet02 Ori A in the Orion Nebula. We measure a value 3He/4He=(1.77+/-0.13)x10^{-4}, which is just ~40 per cent above the primordial relative abundance of these isotopes, assuming the Standard Model of particle physics and cosmology, (3He/4He)_p = (1.257+/-0.017)x10^-4. We calculate a suite of galactic chemical evolution simulations to study the Galactic build up of these isotopes, using the yields from Limongi & Chieffi (2018) for stars in the mass range M=8-100 M_sun and Lagarde (2011,2012) for M=0.8-8 M_sun. We find that these simulations simultaneously reproduce the Orion and protosolar 3He/4He values if the calculations are initialized with a primordial ratio (3He/4He)_p=(1.043+/-0.089)x10^-4. Even though the quoted error does not include the model uncertainty, this determination agrees with the Standard Model value to within ~2sigma. We also use the present-day Galactic abundance of deuterium (D/H), helium (He/H), and 3He/4He to infer an empirical limit on the primordial 3He abundance, (3He/H)_p < (1.09+/-0.18)x10^-5, which also agrees with the Standard Model value. We point out that it is becoming increasingly difficult to explain the discrepant primordial 7Li/H abundance with non-standard physics, without breaking the remarkable simultaneous agreement of three primordial element ratios (D/H, 4He/H, and 3He/4He) with the Standard Model values., 23 pages, 9 figures, Resubmitted to the Astrophysical Journal after addressing referee comments
- Published
- 2022
4. CUBES: the Cassegrain U-band Efficient Spectrograph
- Author
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Stefano Cristiani, Juan Manuel Alcalá, Alencar Silvia, Serj Balashev, Nate Bastian, Beatriz Barbuy, Battino Umberto, Ariadna Calcines Rosario, Giorgio Calderone, Pamela Cambianica, Roberta Carini, Brad Carter, Santi Cassisi, Bruno Castilho, Gabriele Cescutti, Norbert Christlieb, Roberto Cirami, Igor Coretti, Ryan J. Cooke, Stefano Covino, Gabriele Cremonese, Katia Cunha, Guido Cupani, André da Silva, Vincenzo De Caprio, Annalisa De Cia, Hans Dekker, Valerio D'Elia, Gayandhi de Silva, Marcos P. Diaz, Paolo Di Marcantonio, Domenico D'Auria, Valentina D'Odorico, Alan Fitzsimmons, Heitor Ernandes, Chris Evans, Mariagrazia Franchini, Matteo Genoni, Boris Gänsicke, Riano Escate Giribaldi, Clemens D. Gneiding, Andrea Grazian, Camilla Juul Hansen, Fiorangela La Forgia, Marco Landoni, Monica Lazzarin, David Lunney, Walter J. Maciel, Wagner Marcolino, Marcella Marconi, Alessandra Migliorini, Chris Miller, Pasquier Noterdaeme, Cyrielle Opitom, Giorgio Pariani, Bogumil Pilecki, Silvia Piranomonte, Andreas Quirrenbach, Edoardo Maria Alberto Redaelli, Claudio Pereira, Sofia Randich, Silvia Rossi, Ruben Sanchez-Janssen, Walter Seifert, Rodolfo Smiljanic, Colin Snodgrass, Ingo Stilz, Julian Stürmer, Eros Vanzella, Paolo Ventura, Orlando Verducci, Chris Waring, Stephen Watson, Martyn Wells, Duncan Wright, Tayyaba Zafar, and Alessio Zanutta
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Physics - Instrumentation and Detectors ,FOS: Physical sciences ,Instrumentation and Detectors (physics.ins-det) ,Astrophysics - Instrumentation and Methods for Astrophysics ,Instrumentation and Methods for Astrophysics (astro-ph.IM) - Abstract
In the era of Extremely Large Telescopes, the current generation of 8-10m facilities are likely to remain competitive at ground-UV wavelengths for the foreseeable future. The Cassegrain U-Band Efficient Spectrograph (CUBES) has been designed to provide high-efficiency (>40%) observations in the near UV (305-400 nm requirement, 300-420 nm goal) at a spectral resolving power of R>20,000 (with a lower-resolution, sky-limited mode of R ~ 7,000). With the design focusing on maximizing the instrument throughput (ensuring a Signal to Noise Ratio (SNR) ~20 per high-resolution element at 313 nm for U ~18.5 mag objects in 1h of observations), it will offer new possibilities in many fields of astrophysics, providing access to key lines of stellar spectra: a tremendous diversity of iron-peak and heavy elements, lighter elements (in particular Beryllium) and light-element molecules (CO, CN, OH), as well as Balmer lines and the Balmer jump (particularly important for young stellar objects). The UV range is also critical in extragalactic studies: the circumgalactic medium of distant galaxies, the contribution of different types of sources to the cosmic UV background, the measurement of H2 and primordial Deuterium in a regime of relatively transparent intergalactic medium, and follow-up of explosive transients. The CUBES project completed a Phase A conceptual design in June 2021 and has now entered the detailed design and construction phase. First science operations are planned for 2028., SPIE proceedings, SPIE Astronomical Telescopes + Instrumentation 2022, Montr\'eal, Canada; 20 pages, 13 figures, 2 tables
- Published
- 2022
5. MUSE Analysis of Gas around Galaxies (MAGG) – IV. The gaseous environment of z ∼ 3–4 Ly α emitting galaxies
- Author
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Emma K Lofthouse, Michele Fumagalli, Matteo Fossati, Rajeshwari Dutta, Marta Galbiati, Fabrizio Arrigoni Battaia, Sebastiano Cantalupo, Lise Christensen, Ryan J Cooke, Alessia Longobardi, Michael T Murphy, J Xavier Prochaska, K Lofthouse, E, Fumagalli, M, Fossati, M, Dutta, R, Galbiati, M, Arrigoni Battaia, F, Cantalupo, S, Christensen, L, J Cooke, R, Longobardi, A, T Murphy, M, and Xavier Prochaska, J
- Subjects
galaxies: haloe ,galaxies: high-redshift ,Space and Planetary Science ,galaxies: formation ,quasars: absorption line ,Astronomy and Astrophysics ,galaxies: evolution - Abstract
We study the link between galaxies and H i-selected absorption systems at z ∼ 3–4 in the MUSE Analysis of Gas around Galaxies (MAGG) survey, an ESO large programme consisting of integral field spectroscopic observations of 28 quasar fields hosting 61 strong absorbers with $\rm N_{\rm H\,{\small I}}\gtrsim 10^{16.5}~\rm cm^{-2}$. We identify 127 Ly α emitting galaxies (LAEs) around the absorbers, corresponding to a detection rate of 82 ± 16 per cent. The luminosity function of these LAEs is ≈5 times higher in normalization than the field population and we detect a significant clustering of galaxies with respect to the gas, confirming that high column density absorbers and LAEs trace each other. Between 30 and 40 per cent of the absorbers are associated with multiple LAEs, which lie preferentially along filaments. Galaxies in groups also exhibit a three times higher covering factor of optically thick gas compared to isolated systems. No significant correlations are identified between the emission properties of LAEs and the absorption properties of optically thick gas clouds, except for a weak preference of brighter and multiple galaxies to reside near broad absorbers. Based on the measured impact parameters and the covering factor, we conclude that the near totality of optically thick gas in the Universe can be found in the outer circumgalactic medium (CGM) of LAEs or in the intergalactic medium (IGM) in proximity to these galaxies. Thus, LAEs act as tracers of larger scale structures within which both galaxies and optically thick clouds are embedded. The patchy and inhomogeneous nature of the CGM and IGM explains the lack of correlations between absorption and emission properties. This implies that very large samples are needed to unveil the trends that encode the properties of the baryon cycle.
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6. Searching for the Lowest-metallicity Galaxies in the Local Universe.
- Author
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Tiffany Hsyu, Ryan J. Cooke, J. Xavier Prochaska, and Michael Bolte
- Subjects
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DWARF galaxies , *OPTICAL spectroscopy , *PHOTOMETRY ,UNIVERSE - Abstract
We report a method of identifying candidate low-metallicity blue compact dwarf galaxies (BCDs) from the Sloan Digital Sky Survey (SDSS) imaging data, and present 3 m Lick Observatory and 10 m W.M. Keck Observatory optical spectroscopic observations of 94 new systems that have been discovered with this method. The candidate BCDs are selected from Data Release 12 (DR12) of SDSS on the basis of their photometric colors and morphologies. Using the Kast spectrometer on the 3 m telescope, we confirm that the candidate low-metallicity BCDs are emission-line galaxies, and we make metallicity estimates using the empirical R and S calibration methods. Follow-up observations on a subset of the lowest-metallicity systems are made at Keck using the Low Resolution Imaging Spectrometer, which allow for a direct measurement of the oxygen abundance. We determine that 45 of the reported BCDs are low-metallicity candidates with 12 + log(O/H) ≤ 7.65, including six systems which are either confirmed or projected to be among the lowest-metallicity galaxies known, at 1/30 of the solar oxygen abundance, or 12 + log(O/H) ∼ 7.20. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
7. One Percent Determination of the Primordial Deuterium Abundance.
- Author
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Ryan J. Cooke, Max Pettini, and Charles C. Steidel
- Subjects
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DEUTERIUM compounds , *REDSHIFT , *ECHELLE gratings , *NUCLEOSYNTHESIS , *BIG bang theory , *COSMIC background radiation - Abstract
We report a reanalysis of a near-pristine absorption system, located at a redshift toward the quasar Q1243+307, based on the combination of archival and new data obtained with the HIRES echelle spectrograph on the Keck telescope. This absorption system, which has an oxygen abundance [O/H] = −2.769 ± 0.028 (≃1/600 of the solar abundance), is among the lowest metallicity systems currently known where a precise measurement of the deuterium abundance is afforded. Our detailed analysis of this system concludes, on the basis of eight D i absorption lines, that the deuterium abundance of this gas cloud is , which is in very good agreement with the results previously reported by Kirkman et al., but with an improvement on the precision of this single measurement by a factor of ∼3.5. Combining this new estimate with our previous sample of six high precision and homogeneously analyzed D/H measurements, we deduce that the primordial deuterium abundance is or, expressed as a linear quantity, this value corresponds to a one percent determination of the primordial deuterium abundance. Combining our result with a big bang nucleosynthesis (BBN) calculation that uses the latest nuclear physics input, we find that the baryon density derived from BBN agrees to within 2σ of the latest results from the Planck cosmic microwave background data. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
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8. The Little Cub: Discovery of an Extremely Metal-poor Star-forming Galaxy in the Local Universe.
- Author
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Tiffany Hsyu, Ryan J. Cooke, J. Xavier Prochaska, and Michael Bolte
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- 2017
- Full Text
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9. THE PRIMORDIAL DEUTERIUM ABUNDANCE OF THE MOST METAL-POOR DAMPED Lyα SYSTEM.
- Author
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Ryan J. Cooke, Max Pettini, Kenneth M. Nollett, and Regina Jorgenson
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METAL-poor stars , *DEUTERIUM , *ABSORPTION , *MONTE Carlo method , *BIG bang theory , *NUCLEOSYNTHESIS - Abstract
We report the discovery and analysis of the most metal-poor damped Lyα (DLA) system currently known, which also displays the Lyman series absorption lines of neutral deuterium. The average [O/H] abundance of this system is [O/H] = −2.804 ± 0.015, which includes an absorption component with [O/H] = −3.07 ± 0.03. Despite the unfortunate blending of many weak D i absorption lines, we report a precise measurement of the deuterium abundance of this system. Using the six highest-quality and self-consistently analyzed measures of D/H in DLAs, we report tentative evidence for a subtle decrease of D/H with increasing metallicity. This trend must be confirmed with future high-precision D/H measurements spanning a range of metallicity. A weighted mean of these six independent measures provides our best estimate of the primordial abundance of deuterium, 105 (D/H)P = 2.547 ± 0.033 (). We perform a series of detailed Monte Carlo calculations of Big Bang nucleosynthesis (BBN) that incorporate the latest determinations of several key nuclear reaction cross-sections, and propagate their associated uncertainty. Combining our measurement of (D/H)P with these BBN calculations yields an estimate of the cosmic baryon density, 100 ΩB,0h2(BBN) = 2.156 ± 0.020, if we adopt the most recent theoretical determination of the reaction rate. This measure of ΩB,0h2 differs by ∼2.3σ from the Standard Model value estimated from the Planck observations of the cosmic microwave background. Using instead a reaction rate that is based on the best available experimental cross-section data, we estimate 100 ΩB,0h2(BBN) = 2.260 ± 0.034, which is in somewhat better agreement with the Planck value. Forthcoming measurements of the crucial cross-section may shed further light on this discrepancy. [ABSTRACT FROM AUTHOR]
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- 2016
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10. BIG BANG NUCLEOSYNTHESIS AND THE HELIUM ISOTOPE RATIO.
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Ryan J. Cooke
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- 2015
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11. THE HISTORY OF R-PROCESS ENRICHMENT IN THE MILKY WAY.
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Sijing Shen, Ryan J. Cooke, Enrico Ramirez-Ruiz, Piero Madau, Lucio Mayer, and Javiera Guedes
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MILKY Way , *GALAXIES , *GALACTIC evolution , *SUPERNOVAE , *NUCLEOSYNTHESIS - Abstract
We investigate the production sites and the enrichment history of r-process elements in the Galaxy, as traced by the [Eu/Fe] ratio, using the high resolution, cosmological zoom-in simulation “Eris.” At z = 0, Eris represents a close analog to the Milky Way, making it the ideal laboratory to understand the chemical evolution of our Galaxy. Eris formally traces the production of oxygen and iron due to supernovae (SNe) Ia and SNe II. We include in post-processing the production of r-process elements from compact binary mergers. Unlike previous studies, we find that the nucleosynthetic products from compact binary mergers can be incorporated into stars of very low metallicity and at early times, even with a minimum delay time of 100 Myr. This conclusion is relatively insensitive to modest variations in the merger rate, minimum delay time, and the delay time distribution. By implementing a first-order prescription for metal mixing, we can further improve the agreement between our model and the data for the chemical evolution of both [α/Fe] and [Eu/Fe]. We argue that compact binary mergers could be the dominant source of r-process nucleosynthesis in the Galaxy. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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