scholarly journals Abundances in WR Nebulae

1991 ◽  
Vol 143 ◽  
pp. 379-384
Author(s):  
J.M. Vilchez ◽  
C. Esteban
Keyword(s):  
Interstellar Medium ◽  
Chemical Enrichment ◽  
Master List ◽  
Stellar Nucleosynthesis ◽  
Wr Nebulae

Within an ongoing program of long slit spectroscopy of the known WR nebulae, we show here some results for eight objects of the sample selected from the master list of Chu et al. (1983). We present an analysis of their ionisation structure and determine abundances of oxygen, nitrogen and helium in as many positions as possible. The implications of the abundance results for the chemical enrichment of the Interstellar Medium and stellar nucleosynthesis are briefly reviewed.

scholarly journals Distances of Galactic supernova remnants

2013 ◽  
Vol 9 (S296) ◽  
pp. 378-379 ◽  
Author(s):  
Hui Zhu ◽  
Wenwu Tian
Keyword(s):  
Cosmic Rays ◽  
Interstellar Medium ◽  
Supernova Remnants ◽  
Galactic Cosmic Rays ◽  
Distance Measurement ◽  
Explosion Energy ◽  
Chemical Enrichment ◽  
Basic Parameters ◽  
Co Emission

AbstractSupernova remnants (SNRs) play a key role in understanding supernovae explosion mechanisms, exploring the likely sources of Galactic cosmic rays and the chemical enrichment of interstellar medium (ISM). Reliable distance determinations to Galactic SNRs are key to obtain their basic parameters, such as size, age, explosion energy, which helps us to study their environment and interstellar medium. We review the methods to determine the distances to SNRs and highlight the kinematic distance measurement by Hi absorption and CO emission observations.

scholarly journals Chemical enrichment from Wolf-Rayet stellar winds

1999 ◽  
Vol 193 ◽  
pp. 218-226
Author(s):  
Georges Meynet
Keyword(s):  
Angular Velocity ◽  
Interstellar Medium ◽  
Mass Loss ◽  
Solar Nebula ◽  
Cosmic Ray ◽  
Stellar Winds ◽  
Chemical Enrichment ◽  
Galactic Cosmic Ray ◽  
Loss Rates

Stellar winds contribute together with supernovae explosions to the chemical enrichment of the interstellar medium. We recall how the metallicity dependence of the stellar winds implies a metallicity dependence of the stellar yields. We show that an increase of the initial angular velocity has different effects than an increase of the mass loss rates. Wolf-Rayet stars appear as important sources of 19F and 26Al. They are the favoured candidates for the 22Ne anomaly observed in the Galactic cosmic ray sources. They may also have injected into the proto-solar nebula short-lived radionuclides as 26Al, 36Cl, 41Ca, 107Pd and 205Pb.

scholarly journals Star Formation in Disk Galaxies

1998 ◽  
Vol 15 (1) ◽  
pp. 118-122 ◽  
Author(s):  
Rosemary F. G. Wyse ◽  
Annette M. N. Ferguson ◽  
Jay S. Gallagher ◽  
Deidre A. Hunter
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Massive Stars ◽  
Broad Band ◽  
Hii Regions ◽  
Disk Galaxies ◽  
Chemical Enrichment

AbstractWe present results, some preliminary, from a major new study of the star formation properties of a sample of nearby disk galaxies (Ferguson 1997). Our emphasis is on the faint outer regions of disks. Hα images, combined with broad-band images and spectroscopy of HII regions, constrain the present and past star formation rates and chemical enrichment. These data also allow study of faint diffuse ionised gas, which traces the influence of massive stars on their environment, and the structure of the interstellar medium.

scholarly journals Chemical Abundances and Hierarchical Clustering

2004 ◽  
Vol 217 ◽  
pp. 264-265
Author(s):  
P. B. Tissera ◽  
D.G. Lambas
Keyword(s):  
Interstellar Medium ◽  
Hierarchical Clustering ◽  
Stellar Population ◽  
Intergalactic Medium ◽  
Chemical Elements ◽  
Building Blocks ◽  
Chemical Abundances ◽  
Energy Feedback ◽  
Chemical Enrichment ◽  
Central Regions

In this contribution we study the chemical enrichment of the interstellar medium and stellar population of the building blocks of current typical galaxies in the field, in cosmological hydrodynamics simulations. The simulations include detailed modeling of chemical enrichment by SNIa and SNII In our simulations the missing metal problem is caused by chemical elements being locked up in stars, in the central regions (or bulges) mainly. Supernova energy feedback could help to reduce this concentration by expelling metals to the intergalactic medium.

Final Remarks: Connections between Chemical and Dynamical Evolution

1977 ◽  
Vol 45 ◽  
pp. 309-319
Author(s):  
Beatrice M. Tinsley
Keyword(s):  
Interstellar Medium ◽  
Chemical Evolution ◽  
Dynamical Evolution ◽  
Theoretical Background ◽  
Dynamical Processes ◽  
Chemical Enrichment ◽  
The Galaxy ◽  
History Of

Dynamical processes strongly affect the chemical enrichment of gas in galaxies, so abundances in stars and the Interstellar medium can be used as probes of the dynamical history of the Galaxy. By way of tying together some diverse points, rather than summarizing the conference, I shall discuss some examples of connections between chemical and dynamical evolution. The first section of this paper mentions some of the well-known ways in which dynamical processes can affect chemical evolution, in order to outline a theoretical background to the use of abundances as clues to dynamics.

scholarly journals THE FMOS-COSMOS SURVEY OF STAR-FORMING GALAXIES ATz∼ 1.6. IV. EXCITATION STATE AND CHEMICAL ENRICHMENT OF THE INTERSTELLAR MEDIUM

2017 ◽  
Vol 835 (1) ◽  
pp. 88 ◽  
Author(s):  
D. Kashino ◽  
J. D. Silverman ◽  
D. Sanders ◽  
J. S. Kartaltepe ◽  
E. Daddi ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Star Forming ◽  
Chemical Enrichment ◽  
Excitation State

scholarly journals The Evolution of the Mass–Metallicity Relation in Seyferts

2009 ◽  
Vol 5 (S267) ◽  
pp. 144-144
Author(s):  
N. Vale Asari ◽  
G. Stasińska ◽  
R. Cid Fernandes ◽  
J. M. Gomes ◽  
M. Schlickmann ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Emission Line ◽  
Empirical Relation ◽  
Stellar Populations ◽  
Stellar Mass ◽  
Sloan Digital Sky Survey ◽  
Emission Lines ◽  
Chemical Enrichment ◽  
Sky Survey ◽  
History Of

Various studies have shown that there is an empirical relation between the nebular metallicity of a galaxy and its stellar mass. Until now, most studies of the mass-metallicity relation (M–Z) have focused on the abundances of the interstellar medium as measured by emission-line features. This technique thus excludes galaxies with AGN from the working samples, due to the difficulty to measure the nebular abundances when emission-lines are powered both by stars and AGN. With our synthesis code starlight, we are able to recover the stellar metallicities of galaxies from the Sloan Digital Sky Survey (SDSS). Therefore, although we still cannot measure the nebular metallicity in AGN hosts, we know their present-day stellar metallicities. Moreover, because we measure the metallicity of stellar populations of different ages in a galaxy, we are also able also recover the history of its chemical enrichment.

scholarly journals MUSE unravels the ionisation and origin of metal-enriched absorbers in the gas halo of a z = 2.92 radio galaxy

2019 ◽  
Vol 625 ◽  
pp. A102 ◽  
Author(s):  
S. Kolwa ◽  
J. Vernet ◽  
C. De Breuck ◽  
M. Villar-Martín ◽  
A. Humphrey ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Radio Galaxy ◽  
Stellar Winds ◽  
Chemical Enrichment ◽  
Velocity Shift ◽  
The Galaxy ◽  
Spatially Extended ◽  
Nitrogen Abundance ◽  
Circumgalactic Medium ◽  
Projected Distance

We have used the Multi-Unit Spectroscopic Explorer (MUSE) to study the circumgalactic medium (CGM) of a z = 2.92 radio galaxy, MRC 0943−242 by parametrising its emitting and absorbing gas. In both Lyα λ1216 and He II λ1640 lines, we observe emission with velocity shifts of Δv ≃ −1000 km s−1 from the systemic redshift of the galaxy. These blueshifted components represent kinematically perturbed gas that is aligned with the radio axis, and is therefore a signature of jet-driven outflows. Three of the four known Lyα absorbers in this source are detected at the same velocities as C IV λλ1548, 1551 and N V λλ1239, 1243 absorbers, proving that the gas is metal-enriched more so than previously thought. At the velocity of a strong Lyα absorber which has an H I column of NH I/cm−2 = 1019.2 and velocity shift of Δv ≃ −400 km s−1, we also detect Si II λ1260 and Si II λ1527 absorption, which suggests that the absorbing gas is ionisation bounded. With the added sensitivity of this MUSE observation, we are more capable of adding constraints to absorber column densities and consequently determining what powers their ionisation. To do this, we obtain photoionisation grid models in CLOUDY which show that AGN radiation is capable of ionising the gas and producing the observed column densities in a gas of metallicity of Z/Z⊙ ≃ 0.01 with a nitrogen abundance a factor of 10 greater than that of hydrogen. This metal-enriched absorbing gas, which is also spatially extended over a projected distance of r ≳ 60 kpc, is likely to have undergone chemical enrichment through stellar winds that have swept up metals from the interstellar-medium and deposited them in the outer regions of the galaxy’s halo.

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