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We present a new method to derive oxygen and carbon abundances using the ultraviolet (UV) lines emitted by the gas-phase ionised by massive stars. The method is based on the comparison of the nebular emission-line ratios with those…

Astrophysics of Galaxies · Physics 2017-03-13 Enrique Pérez-Montero , Ricardo Amorín

Uncertainty quantification has emerged as a rapidly growing field in nuclear science. Theoretical predictions of physical observables often involve extrapolations to regions that are poorly constrained by laboratory experiments and…

Nuclear Theory · Physics 2020-10-14 Wei-Chia Chen , J. Piekarewicz

Reliable nebular emission line diagnostics are essential for accurately inferring the physical properties (e.g. electron temperature, density, pressure, and metallicity) of H II regions from spectra. When interpreting spectra, it is typical…

Astrophysics of Galaxies · Physics 2026-02-06 Larrance Xing , Nicholas Choustikov , Harley Katz , Alex J. Cameron

Accurately determining the elemental abundances of a low metallicity nebula strongly depends on measuring the density (n$_e$) and temperature (T$_e$) of the gas. Because these two parameters are inherently degenerate when derived solely…

Understanding the evolution of the Milky Way calls for the precise abundance determination of many elements in many stars. A common perception is that deriving more than a few elemental abundances ([Fe/H], [$\alpha$/Fe], perhaps [C/H],…

Solar and Stellar Astrophysics · Physics 2017-07-05 Yuan-Sen Ting , Charlie Conroy , Hans-Walter Rix , Phillip Cargile

Of the light element abundances capable of testing standard big bang nucleosynthesis, only He4 is measured with an accuracy of a few percent. Thus, it is imperative to establish a comprehensive technique for determining He4 abundances and…

Astrophysics · Physics 2007-05-23 Keith A. Olive , Evan D. Skillman

Aim: To determine whether or not gas-phase chemical models with homogeneous and time-independent physical conditions explain the many observed molecular abundances in astrophysical sources, it is crucial to estimate the uncertainties in the…

Astrophysics · Physics 2016-08-15 Valentine Wakelam , Eric Herbst , Franck Selsis , Gérard Massacrier

We present a new methodology for the analysis of the emission lines of the interstellar medium in the Narrow Line Regions around type-2 Active Galactic Nuclei. Our aim is to provide a recipe that can be used for large samples of objects in…

Astrophysics of Galaxies · Physics 2019-09-25 E. Pérez-Montero , O. L. Dors , J. M. Vílchez , R. García-Benito , M. V. Cardaci , G. F. Hägele

For the first time, we establish a gas phase abundance pattern calibration for quiescent galaxies using optical emission lines. Quiescent galaxies have warm ionized gas showing line ratios similar to low-ionization nuclear emission line…

Astrophysics of Galaxies · Physics 2018-09-05 Renbin Yan

We present a method to determine nitrogen abundance ratios with respect to iron ([N/Fe]) from molecular CN-band features observed in low-resolution ($R \sim$ 2000) stellar spectra obtained by the Sloan Digital Sky Survey (SDSS) and the…

Astrophysics of Galaxies · Physics 2022-05-25 Changmin Kim , Young Sun Lee , Timothy C. Beers , Thomas Masseron

Auroral lines enable accurate measurements of chemical abundances in ionized gaseous nebulae thanks to their sensitivity to electron temperature. However, metal-enriched systems remain a challenge, as even deep observations cannot retrieve…

Deep spectroscopy of the planetary nebula (PN) NGC\,6153 shows that its heavy element abundances derived from optical recombination lines (ORLs) are ten times higher than those derived from collisionally excited lines (CELs), and points to…

Solar and Stellar Astrophysics · Physics 2015-05-20 H. -B. Yuan , X. -W. Liu , D. Péquignot , R. H. Rubin , B. Ercolano , Y. Zhang

Although uncertainty quantification has been making its way into nuclear theory, these methods have yet to be explored in the context of reaction theory. For example, it is well known that different parameterizations of the optical…

Nuclear Theory · Physics 2017-03-01 A. E. Lovell , F. M. Nunes , J. Sarich , S. M. Wild

(Abridged) We present the abundance analysis of 12 PNe ionized by [WC]-type stars and wels obtained from high-resolution spectrophotometric data. Our main aims are to determine the chemical composition of the PNe and to study the behaviour…

Astrophysics of Galaxies · Physics 2015-06-17 J. Garcia-Rojas , M. Peña , C. Morisset , G. Delgado-Inglada , A. Mesa-Delgado , M. T. Ruiz

(Abridged) Planetary nebulae (PNe) around Wolf-Rayet [WR] central stars ([WR]PNe) constitute a particular photoionized nebula class that represents about 10% of the PNe with classified central stars. We analyse deep high-resolution…

Astrophysics of Galaxies · Physics 2015-06-03 Jorge García-Rojas , Miriam Peña , Christophe Morisset , Adal Mesa-Delgado , Maria Teresa Ruiz

We present high signal-to-noise spectrophotometric observations of seven luminous HII galaxies. The observations have been made with the use of a double-arm spectrograph which provides spectra with a wide wavelength coverage, from 3400 to…

We discuss the determination of elemental abundances from high resolution X-ray data. We emphasize the need for an accurate determination of the underlying temperature structure and advocate the use of a line ratio method which allows us to…

Astrophysics · Physics 2009-11-10 J. H. M. M. Schmitt , J. -U. Ness

The propagation of uncertainties in reaction cross sections and rates of neutron-, proton-, and $\alpha$-induced reactions into the final isotopic abundances obtained in nucleosynthesis models is an important issue in studies of…

High Energy Astrophysical Phenomena · Physics 2020-12-24 T. Rauscher

We show that ensembling effectively quantifies model uncertainty in Neural Radiance Fields (NeRFs) if a density-aware epistemic uncertainty term is considered. The naive ensembles investigated in prior work simply average rendered RGB…

Computer Vision and Pattern Recognition · Computer Science 2022-09-20 Niko Sünderhauf , Jad Abou-Chakra , Dimity Miller
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