Results 1 to 10 of about 7,840,951 (243)

The Chemical Evolution of Galaxies [PDF]

Proceedings of Frank N. Bash Symposium 2015 — PoS(BASH2015), 2016
The gas-phase oxygen abundance, i.e. metallicity, of a galaxy is set by the interplay between star formation and gas flows. Metals are dispersed into the interstellar medium by stellar winds and supernovae. Metals accumulate in the interstellar medium of star-forming galaxies and provide a record of star-formation.
openaire   +1 more source

On the Chemical Evolution of Our Galaxy [PDF]

Publications of the Astronomical Society of Japan, 1996
We have investigated the chemical evolution of the solar neighborhood with a particular emphasis on the helium abundance and the current supernova (SN) rate, while taking into account the effects of the stellar mass loss on nucleosynthesis in stars. We found that the Scalo IMF can reproduce the solar-helium abundance as well as the current ratio of ...
Kuniko Mihara, Fumio Takahara
openaire   +1 more source

Chemical Abundance Ratios of Nitrogen-rich Galaxies Identified at z ∼ 6–12: Observational Demographics and Models

The Astrophysical Journal
We present chemical abundance ratios of eight nitrogen-rich ([N/O] > 0.3) galaxies at z  ∼ 6–12 identified by the first 4 yr of JWST observations, and compare these ratios with chemical evolution models.
Kuria Watanabe, Masami Ouchi, Kimihiko Nakajima, Nozomu Tominaga, Yuichi Harikane, Miho N. Ishigaki, Yuki Isobe, Minami Nakane, Moka Nishigaki, Ken’ichi Nomoto, Yoshiaki Ono, Masato Onodera, Akihiro Suzuki, Koh Takahashi, Yui Takeda, Hiroto Yanagisawa   +15 more
doaj   +1 more source

Modeling the Ages and Chemical Abundances of Elliptical Galaxies

The Astrophysical Journal
Spectroscopic studies of elliptical galaxies show that their stellar population ages, mean metallicity, and α enhancement traced by [Mg/Fe] all increase with galaxy stellar mass or velocity dispersion.
Nicole Marcelina Gountanis, David H. Weinberg, Aliza G. Beverage, Nathan R. Sandford, Charlie Conroy, Mariska Kriek   +5 more
doaj   +1 more source

Strong He i Emission Lines in High N/O Galaxies at z ∼ 6 Identified in JWST Spectra: High He/H Abundance Ratios or High Electron Densities?

The Astrophysical Journal
We present He i /H β flux and He/H abundance ratios in three James Webb Space Telescope galaxies with significant constraints on N/O abundance ratios, GS-NDG-9422, RXCJ2248-ID, and GLASS150008 at z ∼ 6 mostly with the spectroscopic coverage from He i λ ...
Hiroto Yanagisawa, Masami Ouchi, Kuria Watanabe, Akinori Matsumoto, Kimihiko Nakajima, Hidenobu Yajima, Kentaro Nagamine, Koh Takahashi, Minami Nakane, Nozomu Tominaga, Hiroya Umeda, Hajime Fukushima, Yuichi Harikane, Yuki Isobe, Yoshiaki Ono, Yi Xu, Yechi Zhang   +16 more
doaj   +1 more source

INHOMOGENEITIES OF CHEMICAL COMPOSITION AND COSMOCHRONOLOGY PROBLEMS

Odessa Astronomical Publications, 2017
The problems of determination of chemical composition of stars and connection with theory of chemical evolution of Galaxy are discussed.
V. G. Klochkova, V. E. Panchuk
doaj   +1 more source

The Disrupted Chemical Enrichment History of the Milky Way Driven by Gas Accretion

The Astrophysical Journal Letters
As the only galaxy enabling temporally resolved observations from an internal vantage point, the Milky Way as a galaxy offers unique insights into galactic chemical enrichment history, establishment of fundamental scaling relations, and the underlying ...
Jianhui Lian, Qinhao Shao, Min Du, Hanyuan Zhang, Xinxin Duan, Xin Wang, Zheng Zheng   +6 more
doaj   +1 more source

Gas-phase Metallicity of Local Active Galactic Nuclei in the GASP and MaNGA Surveys: The Role of Ram Pressure Stripping

The Astrophysical Journal, 2023
Growing evidence in support of a connection between active galactic nuclei (AGN) activity and the ram pressure stripping (RPS) phenomenon has been found both observationally and theoretically in the past decades.
Giorgia Peluso, Mario Radovich, Alessia Moretti, Matilde Mingozzi, Benedetta Vulcani, Bianca M. Poggianti, Antonino Marasco, Marco Gullieuszik   +7 more
doaj   +1 more source

A model for the chemical evolution of the galaxy with refuses

Astrophysics and Space Science, 1994
11 pages (figures and table upon request), Tex, Ap.Spac.Sci. (in press)
Rocha-Pinto, Helio J., Arany-Prado, Lilia I., Maciel, Walter J.   +2 more
openaire   +2 more sources

Stellar Populations with MaNGA: Iron Kink and Nitrogen Fuzz

The Astrophysical Journal
Recent analysis of 2968 MaNGA early-type galaxies has yielded two notable trends with velocity dispersion ( σ ) not previously discussed in the literature. First, Fe abundance rises with σ but only until σ  ≈ 100 km s ^−1 , after which it falls.
Guy Worthey, Tathagata Pal
doaj   +1 more source