Results 11 to 20 of about 4,473,250 (366)

Chemical abundances in active galaxies [PDF]

Monthly Notices of the Royal Astronomical Society, 2020
The Sloan Digital Sky Survey (SDSS) has proved to be a powerful resource for understanding the physical properties and chemical composition of star-forming galaxies in the local universe.
S. Flury, E. Moran
semanticscholar   +4 more sources

Chemical Abundances from the Continuum [PDF]

Physica Scripta, 2008
The calculation of solar absolute fluxes in the near-UV is revisited, discussing in some detail recent updates in theoretical calculations of bound-free opacity from metals.
Allende Prieto C, Allende Prieto C, Allende Prieto C, Asplund M, Bautista M A, C Allende Prieto, Cunto W, Hubeny I Lanz T, Koesterke L, Nahar S N, Sbordone L   +10 more
core   +2 more sources

Origin of cosmic chemical abundances [PDF]

Monthly Notices of the Royal Astronomical Society, 2015
Cosmological N-body hydrodynamic computations following atomic and molecular chemistry (e$^-$, H, H$^+$, H$^-$, He, He$^+$, He$^{++}$, D, D$^+$, H$_2$, H$_2^+$, HD, HeH$^+$), gas cooling, star formation and production of heavy elements (C, N, O, Ne, Mg ...
U. Maio, E. Tescari
semanticscholar   +4 more sources

Chemical Abundances of Planetary Nebulae in M33 [PDF]

Astronomy & Astrophysics, 2004
Using spectroscopic data presented in Magrini et al. (2003), we have analyzed with the photoionization code CLOUDY 94.00 (Ferland et al. 1998) 11 Planetary Nebulae belonging to the spiral galaxy M 33. Central star temperatures and nebular parameters have
A. Mampaso, Ambartsumian, Armsdorfer, Che, Corradi, Costa, Dufour, Exter, Ferland, Gurzadyan, Henry, Howard, Iben, Jacoby, Jacoby, Jacoby, Kingsburgh, L. Magrini, Leisy, M. Perinotto, Magrini, Mampaso, Maran, Morisset, Peimbert, Perinotto, Phillips, R. L. M. Corradi, Rauch, Richer, Stasinska, Vílchez, Walsh, Walsh   +33 more
core   +2 more sources

Chemical abundances in Seyfert galaxies – VIII. Argon abundance estimates [PDF]

Monthly Notices of the Royal Astronomical Society, 2021
ABSTRACT For the first time, the argon abundance relative to hydrogen abundance (Ar/H) in the narrow line region of a sample of Seyfert 2 nuclei has been derived. In view of this, optical narrow emission line intensities of a sample of 64 local Seyfert 2 nuclei (z < 0.25) taken from Sloan Digital Sky Survey DR7 and measured by the
A F Monteiro, O L Dors
  +7 more sources

Chemical abundances of Seyfert 2 AGNs – III. Reducing the oxygen abundance discrepancy [PDF]

Monthly Notices of the Royal Astronomical Society, 2020
ABSTRACT We investigate the discrepancy between oxygen abundance estimations for narrow-line regions of active galactic nuclei (AGNs) type Seyfert 2 derived using direct estimations of the electron temperature (Te-method) and those derived using photoionization models.
O. L. Dors, R. Maiolino, M. V. Cardaci, G. F. Hägele, A. C. Krabbe, E. Pérez‐Montero, Mark Armah   +6 more
openalex   +6 more sources

Chemical abundances in the nuclear region of nearby galaxies from the Palomar Survey [PDF]

, 2021
We estimate chemical abundances and ionization parameters in the nuclear region of a sample of 143 galaxies from the Palomar Spectroscopic Survey, composed by Star-Forming Galaxies (87), Seyferts 2 (16) and LINERs (40) using the Hii-Chi-mistry code.
B. P'erez-D'iaz, J. Masegosa, I. M'arquez, Enrique P'erez-Montero Instituto de Astrof'isica de Andaluc'ia, Granada, Spain   +5 more
semanticscholar   +1 more source

High-precision chemical abundances of Galactic building blocks. The distinct chemical abundance sequence of Sequoia

Astronomy & Astrophysics, 2021
Context. Sequoia is a retrograde kinematic substructure in the nearby Galactic halo, whose properties are a matter of debate. For example, previous studies do not necessarily agree on the chemical abundances of Sequoia stars, which are important for understanding its nature. Aims.
Tadafumi Matsuno, Helmer H. Koppelman, A. Helmi, Wako Aoki, Miho N. Ishigaki, Takuma Suda, Zhen Yuan, Kohei Hattori   +7 more
openalex   +4 more sources

The Open Cluster Chemical Abundances and Mapping Survey. IV. Abundances for 128 Open Clusters Using SDSS/APOGEE DR16 [PDF]

Astronomical Journal, 2020
The Open Cluster Chemical Abundances and Mapping (OCCAM) survey aims to constrain key Galactic dynamical and chemical evolution parameters by the construction of a large, comprehensive, uniform, infrared-based spectroscopic data set of hundreds of open ...
J. Donor, P. Frinchaboy, K. Cunha, J. O’Connell, C. Prieto, Andrés Almeida, F. Anders, R. Beaton, D. Bizyaev, J. Brownstein, R. Carrera, C. Chiappini, R. Cohen, D. A. García-Hernández, D. Geisler, S. Hasselquist, H. Jönsson, R. Lane, S. Majewski, D. Minniti, C. M. Bidin, K. Pan, A. Roman-Lopes, J. Sobeck, G. Zasowski   +24 more
semanticscholar   +1 more source

SPCANet: Stellar Parameters and Chemical Abundances Network for LAMOST-II Medium Resolution Survey [PDF]

Astrophysical Journal, 2020
The fundamental stellar atmospheric parameters (Teff and log g) and 13 chemical abundances are derived for medium-resolution spectroscopy from Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) Medium Resolution Survey (MRS) data sets ...
Rui Wang, A. Luo, Jian-Jun Chen, W. Hou, Shuo Zhang, Yongheng Zhao, Xiangru Li, Yong-Hui Hou   +7 more
semanticscholar   +1 more source