Chemical evolution, stellar nucleosynthesis, and a variable star formation rate

1987 ◽  
Vol 313 ◽  
pp. 813 ◽  
Author(s):  
Keith A. Olive ◽  
Friedrich-Karl Thielemann ◽  
James W. Truran
Keyword(s):  
Star Formation ◽  
Chemical Evolution ◽  
Variable Star ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Stellar Nucleosynthesis

scholarly journals Evolution of the star formation efficiency in galaxies

2012 ◽  
Vol 10 (H16) ◽  
pp. 341-341
Author(s):  
Jonathan Braine
Keyword(s):  
Star Formation ◽  
Chemical Evolution ◽  
Conversion Factor ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Molecular Gas ◽  
Present Evidence ◽  
Ngc 6822 ◽  
Physical And Chemical ◽  
Formation Efficiency

AbstractThe physical and chemical evolution of galaxies is intimately linked to star formation, We present evidence that molecular gas (H2) is transformed into stars more quickly in smaller and/or subsolar metallicity galaxies than in large spirals – which we consider to be equivalent to a star formation efficiency (SFE). In particular, we show that this is not due to uncertainties in the N(H2)/Ico conversion factor. Several possible reasons for the high SFE in galaxies like the nearby M33 or NGC 6822 are proposed which, separately or together, are the likely cause of the high SFE in this environment. We then try to estimate how much this could contribute to the increase in cosmic star formation rate density from z = 0 to z = 1.

scholarly journals DustPedia: the relationships between stars, gas, and dust for galaxies residing in different environments

2019 ◽  
Vol 626 ◽  
pp. A63 ◽  
Author(s):  
J. I. Davies ◽  
A. Nersesian ◽  
M. Baes ◽  
S. Bianchi ◽  
V. Casasola ◽  
...  
Keyword(s):  
Star Formation ◽  
Chemical Evolution ◽  
Star Formation Rate ◽  
Local Density ◽  
Formation Rate ◽  
Virgo Cluster ◽  
Star Formation History ◽  
Mass Ratio ◽  
Field Samples ◽  
Dust Mass

We use a sub-set of the DustPedia galaxy sample (461 galaxies) to investigate the effect the environment has had on galaxies. We consider Virgo cluster and field samples and also assign a density contrast parameter to each galaxy, as defined by the local density of SDSS galaxies. We consider their chemical evolution (using MDust/MBaryon and MGas/MBaryon), their specific star formation rate (SFR/MStars), star formation efficiency (SFR/MGas), stars-to-dust mass ratio (MStars/MDust), gas-to-dust mass ratio (MGas/MDust) and the relationship between star formation rate per unit mass of dust and dust temperature (SFR/MDust and TDust). Late type galaxies (later than Sc) in all of the environments can be modelled using simple closed box chemical evolution and a simple star formation history (SFR(t) ∝ t exp−t/τ). For earlier type galaxies the physical mechanisms that give rise to their properties are clearly much more varied and require a more complicated model (mergers, gas in or outflow). However, we find little or no difference in the properties of galaxies of the same morphological type within the cluster, field or with different density contrasts. It appears that it is morphology, how and whenever this is laid down, and consistent internal physical processes that primarily determine the derived properties of galaxies in the DustPedia sample and not processes related to differences in the local environment.

scholarly journals Chemical Evolution in Hierarchical Clustering Scenarios

2004 ◽  
Vol 217 ◽  
pp. 258-263
Author(s):  
Patricia B. Tissera ◽  
Cecilia Scannapieco
Keyword(s):  
Star Formation ◽  
Energy Distribution ◽  
Chemical Evolution ◽  
Star Formation Rate ◽  
Spectral Synthesis ◽  
Formation Rate ◽  
First Results ◽  
History Of ◽  
Chemical History ◽  
The Impact

We present first results of an implementation of chemical evolution in a cosmological hydrodynamical code, focusing the analysis on the effects of cooling baryons according to their metallicity. We found that simulations with primordial cooling can underestimate the star formation rate from z < 3 and by up to ≈ 20%. We constructed simulated spectra by combining the star formation and chemical history of galactic systems with spectral synthesis models and assess the impact of chemical evolution on the energy distribution.

scholarly journals Baryonic inflow and outflow histories in disk galaxies as revealed from observations of distant star-forming galaxies

2015 ◽  
Vol 11 (S317) ◽  
pp. 356-357
Author(s):  
Daisuke Toyouchi ◽  
Masashi Chiba
Keyword(s):  
Star Formation ◽  
Chemical Evolution ◽  
Milky Way ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Chemical Abundance ◽  
Star Forming ◽  
Distant Star ◽  
Fundamental Information ◽  
Outflow Rate

AbstractGas inflow and outflow are the most important processes, which determine the structural and chemical evolution of a disk galaxy like the Milky Way. In order to get new insights into these baryonic processes in Milky Way like galaxies (MWLGs), we consider the data of distant star-forming galaxies and investigate the evolution of the radial density profile of their stellar components and the associated total amount of gaseous inflow and outflow. For this purpose, we analyze the redshift evolution of their stellar mass distribution, combined with the scaling relations between the mass of baryonic components, star formation rate and chemical abundance for both high- and low-z star-forming galaxies. As a result, we find the new relations between star formation rate and inflow/outflow rate as deduced from these distant galaxies, which will provide fundamental information for understanding the structural and chemical evolution of MWLGs.

The evolution of the oxygen radial gradients in spiral galaxies

2018 ◽  
Vol 14 (A30) ◽  
pp. 265-265
Author(s):  
M. Mollá ◽  
O. Cavichia ◽  
B. Gibson ◽  
P. Tissera ◽  
P. Sánchez-Blázquez ◽  
...  
Keyword(s):  
Star Formation ◽  
Chemical Evolution ◽  
Spiral Galaxies ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Stellar Mass ◽  
Radial Gradient

AbstractWe analyse the evolution with redshift of the radial gradient of oxygen abundances in spiral disks resulting from our MULCHEM chemical evolution models, computed for galaxies of different sizes or masses, studying the relationships between the gradients and galaxy characteristics as the stellar mass, the size, the gas fraction or the star formation rate for z < 4.

scholarly journals Why galaxies care about Type Ia supernovae?

2014 ◽  
Vol 10 (S309) ◽  
pp. 206-209
Author(s):  
Noelia Jiménez ◽  
Patricia B. Tissera ◽  
Francesca Matteucci
Keyword(s):  
Star Formation ◽  
Chemical Evolution ◽  
Galaxy Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Host Galaxy ◽  
Type Ia Supernovae ◽  
The Galaxy ◽  
Type Ia ◽  
Ia Supernovae

AbstractWe implement the Single Degenerate (SD) scenario proposed for Type Ia Supernova (SNIa) progenitors in SPH simulations. We analyse the chemical evolution of bulge-type galaxies together with the observed correlations relating SNIa rates with the characteristics of the host galaxy, such as their SFR. The models reproduce the observed signatures shown by [O/Fe] ratios in the Galactic Bulge and the present day SNIa rates. Also, the observed correlation found by Sullivan et al. (2006) between SSFR (specific star formation rate) and the SNIa rate per unit of galaxy mass (SSNIaR), naturally arises. This analysis helps to set more stringent constraints to the galaxy formation models and gives some hint on the progenitor problem.

scholarly journals Chemical Evolution of the Magellanic Clouds

1984 ◽  
Vol 108 ◽  
pp. 95-96
Author(s):  
Francesca Matteucci
Keyword(s):  
Star Formation ◽  
Chemical Evolution ◽  
Formation Process ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Magellanic Clouds ◽  
Continuous Mode ◽  
Formation Theory ◽  
Star Formation Activity

According to the stochastic self propagating star formation theory (SSPSF, Gerola and Seiden, 1978), the star formation process in galaxies changes from a fluctuating but continuous mode to a bursting one, when the size of the system becomes relatively small (R ≤ 3 Kpc). Then, due to its size, the LMC should be a system undergoing fluctuating but continuous star formation activity, whereas the SMC should be in the region between continuous and bursting modes (Gerola et al. 1980). In order to look better inside this problem a model of chemical evolution of the two Clouds, which takes into account the stochastic star formation rate, has been built. For the SMC both the continuous and the bursting modes of star formation have been considered. As a result we find that the different chemical histories of the two Clouds may be related to the fact that SMC has undergone several bursts of star formation (between 50 and 60), while a continuous star formation activity was present in LMC.

scholarly journals Properties of galaxies with an offset between the position angles of the major kinematic and photometric axes

2020 ◽  
Vol 634 ◽  
pp. A26 ◽  
Author(s):  
L. S. Pilyugin ◽  
E. K. Grebel ◽  
I. A. Zinchenko ◽  
J. M. Vílchez ◽  
F. Sakhibov ◽  
...  
Keyword(s):  
Star Formation ◽  
Surface Brightness ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Velocity Fields ◽  
Oxygen Abundance ◽  
Star Forming ◽  
Measured Position ◽  
Central Oxygen ◽  
Straight Lines

We derive the photometric, kinematic, and abundance characteristics of 18 star-forming MaNGA galaxies with fairly regular velocity fields and surface brightness distributions and with a large offset between the measured position angles of the major kinematic and photometric axes, ΔPA ≳ 20°. The aim is to examine if there is any other distinctive characteristic common to these galaxies. We found morphological signs of interaction in some (in 11 out of 18) but not in all galaxies. The observed velocity fields show a large variety; the maps of the isovelocities vary from an hourglass-like appearance to a set of straight lines. The position angles of the major kinematic axes of the stellar and gas rotations are close to each other. The values of the central oxygen abundance, radial abundance gradient, and star formation rate are distributed within the intervals defined by galaxies with small (no) ΔPA of similar mass. Thus, we do not find any specific characteristic common to all galaxies with large ΔPA. Instead, the properties of these galaxies are similar to those of galaxies with small (no) ΔPA. This suggests that either the reason responsible for the large ΔPA does not influence other characteristics or the galaxies with large ΔPA do not share a common origin, they can, instead, originate through different channels.

Sign in / Sign up

Export Citation Format

Share Document