scholarly journals The chemical evolution of the Galaxy

1985 ◽  
Vol 106 ◽  
pp. 587-596
Author(s):  
Bruce A. Twarog
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Chemical Evolution ◽  
Gas Dynamics ◽  
Common Point ◽  
Galactic Chemical Evolution ◽  
Stellar Nucleosynthesis ◽  
Double Edge ◽  
The Galaxy ◽  
Double Edge Sword

Over the last few years, our picture of the chemical evolution of the Galaxy has changed substantially. These changes are of interest because chemical evolution provides a common point of contact for most astrophysical processes of importance to galaxy evolution. By astrophysical processes we mean star formation, stellar nucleosynthesis, gas dynamics, etc. An understanding of galactic chemical evolution would allow us to place constraints on all of these topics simultaneously. This property, however, is a double-edge sword because, with so many variables involved, unique solutions to problems in chemical evolution are almost impossible.

scholarly journals The Rate of Supernovae in Normal Galaxies

1996 ◽  
Vol 171 ◽  
pp. 81-84
Author(s):  
Enrico Cappellaro
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Chemical Evolution ◽  
Stellar Evolution ◽  
Star Formation History ◽  
Individual Stars ◽  
Normal Galaxies ◽  
Formation History ◽  
The Galaxy ◽  
Chemical Content

The rate of supernovae (SNe) is a key number linking stellar evolution with galaxy evolution models. Stellar evolution theories predict life times, fates and nucleosysntesis yields of individual stars which are used to predicted the galaxy chemical evolution once the star formation history in the galaxy is known. Constraints to the models are the present chemical content of galaxies but also the present observed SN rate (Arimoto & Yoshi, 1987; Ferrini & Poggianti, 1993; Matteucci, 1994; Renzini et al., 1993; Bressan et al., 1994; Elbaz et al., 1995).

scholarly journals How to Model the Chemical Evolution of Galaxies

1993 ◽  
Vol 155 ◽  
pp. 557-566
Author(s):  
Joachim Köppen
Keyword(s):  
Star Formation ◽  
Chemical Evolution ◽  
Time Scale ◽  
Life Time ◽  
Magellanic Clouds ◽  
Formation Time ◽  
List Type ◽  
The Galaxy ◽  
H Ii Region ◽  
Magellanic Stream

For a first interpretation of the comparison of observational data, the crude “Simple Model” of chemical evolution is quite useful. Since it has well been described in the literature (e.g. Pagel and Patchett 1975, Tinsley 1980), let us here just review the assumptions and whether they are satisfied: 1.The galaxy is a closed system, with no exchange of matter with its surroundings: For the solar neighbourhood this probably is not true (the infamous Gdwarf-“problem”, Pagel 1989b). For the Magellanic Clouds this is most certainly wrong, because of the presence of the Inter-Cloud Region and the Magellanic Stream, and evidence for interaction with each other and the Galaxy as well (cf. e.g. Westerlund 1990).2.It initially consists entirely of gas (without loss of generality of primordial composition): This is good approximation also for models with gas infall, as long as the infall occurs with a time scale shorter than the star formation time scale.3.The metal production of the average stellar generation (the yield y) is constant with time: Initially, it is reasonable to make this assumption. For tables of the oxygen yield see Koppen and Arimoto (1991).4.The metal rich gas ejected by the stars is completely mixed with the ambient gas. To neglect the finite stellar life times (“instantaneous recycling approximation”) is appropriate for elements synthesized in stars whose life time is much shorter than the star formation time scale, such as oxygen, neon, sulphur, and argon.5.The gas is well mixed at all times: We don't know. The dispersion of H II region abundances may give an indication. In the Magellanic Clouds Dufour (1984) finds quite a low value (±0.08 dex for oyxgen).

Presolar Al2O3 grains as probes of stellar nucleosynthesis and galactic chemical evolution

1997 ◽  
Vol 621 (1-2) ◽  
pp. 113-116 ◽  
Author(s):  
L.R. Nittler ◽  
C.M.O'D. Alexander ◽  
X. Gao ◽  
R.M. Walker ◽  
E. Zinner
Keyword(s):  
Chemical Evolution ◽  
Galactic Chemical Evolution ◽  
Stellar Nucleosynthesis

scholarly journals Gas accretion regulates the scatter of the mass–metallicity relation

2020 ◽  
Vol 498 (3) ◽  
pp. 3215-3227
Author(s):  
Gabriella De Lucia ◽  
Lizhi Xie ◽  
Fabio Fontanot ◽  
Michaela Hirschmann
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Formation Rate ◽  
Gas Content ◽  
Stellar Feedback ◽  
Accretion Rates ◽  
The Galaxy ◽  
Gas Cooling ◽  
Gas Accretion ◽  
Cold Gas

ABSTRACT In this paper, we take advantage of the GAlaxy Evolution and Assembly (GAEA) semi-analytic model to analyse the origin of secondary dependencies in the local galaxy mass–gas metallicity relation. Our model reproduces quite well the trends observed in the local Universe as a function of galaxy star formation rate and different gas-mass phases. We show that the cold gas content (whose largest fraction is represented by the atomic gas phase) can be considered as the third parameter governing the scatter of the predicted mass–metallicity relation, in agreement with the most recent observational measurements. The trends can be explained with fluctuations of the gas accretion rates: a decrease of the gas supply leads to an increase of the gas metallicity due to star formation, while an increase of the available cold gas leads to a metallicity depletion. We demonstrate that the former process is responsible for offsets above the mass–metallicity relation, while the latter is responsible for deviations below the mass–metallicity relation. In low- and intermediate-mass galaxies, these negative offsets are primarily determined by late gas cooling dominated by material that has been previously ejected due to stellar feedback.

scholarly journals Mentari: A pipeline to model the galaxy SED using semi analytic models

2019 ◽  
Vol 15 (S341) ◽  
pp. 119-123
Author(s):  
Dian Triani ◽  
Darren Croton ◽  
Manodeep Sinha
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Spectral Energy Distribution ◽  
Cosmic Time ◽  
Spectral Energy ◽  
Chemical Enrichment ◽  
The Galaxy ◽  
History Of ◽  
Gas Accretion ◽  
Analytic Models

AbstractWe build a theoretical picture of how the light from galaxies evolves across cosmic time. In particular, we predict the evolution of the galaxy spectral energy distribution (SED) by carefully integrating the star formation and metal enrichment histories of semi-analytic model (SAM) galaxies and combining these with stellar population synthesis models which we call mentari. Our SAM combines prescriptions to model the interplay between gas accretion, star formation, feedback process, and chemical enrichment in galaxy evolution. From this, the SED of any simulated galaxy at any point in its history can be constructed and compared with telescope data to reverse engineer the various physical processes that may have led to a particular set of observations. The synthetic SEDs of millions of simulated galaxies from mentari can cover wavelengths from the far UV to infrared, and thus can tell a near complete story of the history of galaxy evolution.

scholarly journals Carbon Isotopic Chemistry

1992 ◽  
Vol 150 ◽  
pp. 193-197
Author(s):  
W. D. Langer
Keyword(s):  
Chemical Evolution ◽  
Galactic Chemical Evolution ◽  
Interstellar Clouds ◽  
Carbon Isotopic ◽  
The Galaxy ◽  
Molecular Abundances

Isotopic molecular abundances are used to interpret Galactic chemical evolution and the properties of interstellar clouds. The isotopic chemistry of carbon plays an important role in the interpretation of these measurements. This paper reviews the recent measurements of the carbon twelve to thirteen ratio across the Galaxy and the isotopic chemistry.

Developing an astrophysical line list for Keck/Nirspec observations of red giants in the Galactic centre

2017 ◽  
Vol 13 (S334) ◽  
pp. 372-373 ◽  
Author(s):  
B. Thorsbro ◽  
N. Ryde ◽  
R. M. Rich ◽  
M. Schultheis ◽  
T. K. Fritz ◽  
...  
Keyword(s):  
Chemical Evolution ◽  
Wavelength Region ◽  
Galactic Centre ◽  
Red Giants ◽  
The Sun ◽  
Galactic Chemical Evolution ◽  
Line List ◽  
Stellar Spectroscopy ◽  
Near Ir ◽  
The Galaxy

AbstractA major avenue in the study of the Galaxy is the investigation of stellar populations and Galactic chemical evolution by stellar spectroscopy. Due to the dust obscuration, stars in the centre of the Galaxy can only be observed in the near-IR wavelength region. However, existing line lists in this wavelength region are demonstratively not of good enough quality for use in stellar spectroscopy. In response to this, we have developed an empirical astrophysical line list in the K-band based on modelling against the Sun and testing against Arcturus. Of ca. 700 identified interesting lines about 570 lines have been assigned empirically determined values.

Sign in / Sign up

Export Citation Format

Share Document