scholarly journals Element abundance ratios in stellar population modelling

2014 ◽  
Vol 10 (S311) ◽  
pp. 63-68
Author(s):  
Daniel Thomas
Keyword(s):  
Globular Clusters ◽  
Stellar Population ◽  
Chemical Elements ◽  
Element Abundance ◽  
Early Type ◽  
Population Modelling ◽  
The Past ◽  
Wide Range ◽  
Recent Developments ◽  
Absorption Features

AbstractI review the implementation of the effects from varying chemical element abundance ratios in stellar population modelling, focusing on α- and Fe-peak elements. A brief overview of the development of such models over the past 30 years is provided, starting with early work on the identification of relevant absorption features in the spectra of early-type galaxies in the 1980s leading to the most recent developments of the past years. Recent highlights include the adoption of new flux calibrated libraries, the inclusion of a wide range of chemical elements, the calculation of error estimates on the model, and the consideration of element variation effects on full spectra. The calibration of such models with globular clusters and some key results on the element ratios measured in early-type galaxies are presented.

scholarly journals Element abundance ratios in stellar population modelling

2015 ◽  
Vol 11 (A29B) ◽  
pp. 188-189
Author(s):  
Daniel Thomas
Keyword(s):  
Error Estimates ◽  
Chemical Element ◽  
Stellar Population ◽  
Chemical Elements ◽  
Element Abundance ◽  
Early Type ◽  
Population Modelling ◽  
Element Ratios ◽  
Wide Range ◽  
Element Variation

AbstractI review the implementation of the effects from varying chemical element abundance ratios in stellar population modelling. Recent highlights include the adoption of new flux calibrated libraries, the inclusion of a wide range of chemical elements, the calculation of error estimates on the model, and the consideration of element variation effects on full spectra. Some key results on the element ratios measured in early-type galaxies are discussed.

scholarly journals Fornax3D project: Overall goals, galaxy sample, MUSE data analysis, and initial results

2018 ◽  
Vol 616 ◽  
pp. A121 ◽  
Author(s):  
M. Sarzi ◽  
E. Iodice ◽  
L. Coccato ◽  
E. M. Corsini ◽  
P. T. de Zeeuw ◽  
...  
Keyword(s):  
Spectroscopic Data ◽  
Globular Clusters ◽  
Sample Selection ◽  
Element Abundance ◽  
Early Type ◽  
Population Modelling ◽  
Stellar Kinematics ◽  
High Quality ◽  
Cluster Galaxies ◽  
Initial Results

The Fornax cluster provides a uniquely compact laboratory in which to study the detailed history of early-type galaxies and the role played by the environment in driving their evolution and their transformation from late-type galaxies. Using the superb capabilities of the Multi Unit Spectroscopic Explorer on the Very Large Telescope, high-quality integral-field spectroscopic data were obtained for the inner regions of all the bright (mB ≤ 15) galaxies within the virial radius of Fornax. The stellar haloes of early-type galaxies are also covered out to about four effective radii. State-of-the-art stellar dynamical and population modelling allows characterising the disc components of fast-rotating early-type galaxies, constraining radial variations in the stellar initial-mass functions and measuring the stellar age, metallicity, and α-element abundance of stellar haloes in cluster galaxies. This paper describes the sample selection, observations, and overall goals of the survey, and provides initial results based on the spectroscopic data, including the detailed characterisation of stellar kinematics and populations to large radii; decomposition of galaxy components directly via their orbital structure; the ability to identify globular clusters and planetary nebulae, and derivation of high-quality emission-line diagnostics in the presence of complex ionised gas.

scholarly journals Bio-Based Alternatives to Phenol and Formaldehyde for the Production of Resins

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2237 ◽  
Author(s):  
P. R. Sarika ◽  
Paul Nancarrow ◽  
Abdulrahman Khansaheb ◽  
Taleb Ibrahim
Keyword(s):  
Raw Materials ◽  
Phenol Formaldehyde ◽  
Raw Material ◽  
Wood Industry ◽  
Suitable Material ◽  
The Past ◽  
Wide Range ◽  
Recent Developments ◽  
Sustainable Materials ◽  
Materials Used

Phenol–formaldehyde (PF) resin continues to dominate the resin industry more than 100 years after its first synthesis. Its versatile properties such as thermal stability, chemical resistance, fire resistance, and dimensional stability make it a suitable material for a wide range of applications. PF resins have been used in the wood industry as adhesives, in paints and coatings, and in the aerospace, construction, and building industries as composites and foams. Currently, petroleum is the key source of raw materials used in manufacturing PF resin. However, increasing environmental pollution and fossil fuel depletion have driven industries to seek sustainable alternatives to petroleum based raw materials. Over the past decade, researchers have replaced phenol and formaldehyde with sustainable materials such as lignin, tannin, cardanol, hydroxymethylfurfural, and glyoxal to produce bio-based PF resin. Several synthesis modifications are currently under investigation towards improving the properties of bio-based phenolic resin. This review discusses recent developments in the synthesis of PF resins, particularly those created from sustainable raw material substitutes, and modifications applied to the synthetic route in order to improve the mechanical properties.

scholarly journals Using MUSE-AO observations to constrain the formation of the large nuclear star cluster in FCC 47

2019 ◽  
Vol 14 (S351) ◽  
pp. 108-111
Author(s):  
Katja Fahrion ◽  
Mariya Lyubenova ◽  
Glenn van de Ven ◽  
Michael Hilker
Keyword(s):  
Globular Clusters ◽  
Stellar Population ◽  
Host Galaxy ◽  
Wide Field ◽  
Early Type ◽  
Gas Reservoir ◽  
External Galaxies ◽  
Integral Field ◽  
Early Type Galaxy

AbstractNuclear star clusters (NSCs) are found in at least 70% of all galaxies, but their formation path is still unclear. In the most common scenarios, NSCs form in-situ from the galaxy’s central gas reservoir, through merging of globular clusters (GCs), or through a combination of the two. As the scenarios pose different expectations for angular momentum and stellar population properties of the NSC in comparison to the host galaxy and the GC system, it is necessary to characterise the stellar light, NSC, and GCs simultaneously. Wide-field observations with modern integral field units such as the Multi Unit Spectroscopic Explorer (MUSE) allow to perform such studies. However, at large distances, NSCs usually are not resolved in MUSE observations. The particularly large NSC (Reff ∼ 66 pc) of the early-type galaxy FCC 47 at distance of ∼20 Mpc is an exception and is therefore an ideal laboratory to constrain NSC formation of external galaxies.

scholarly journals XMM-Newton observations of elliptical galaxies in the local universe

2009 ◽  
Vol 5 (H15) ◽  
pp. 273-273
Author(s):  
Ginevra Trinchieri
Keyword(s):  
Globular Clusters ◽  
Large Scale ◽  
Spectral Characteristics ◽  
Large Field ◽  
Specific Class ◽  
Early Type ◽  
X Ray ◽  
Compact Source ◽  
Wide Range ◽  
The Individual

XMM-Newton is well suited to the study of the X-ray properties of early-type galaxies: the wide energy band allows a characterization of the different components of the X-ray emission in galaxies, separating the gas from the compact source component through their spectral characteristics, and identifying low-luminosity absorbed AGNs; the large field of view allows a proper understanding of the large scale emission, and the separation between the galaxy and the surrounding group. Nonetheless, in spite of the much improved understanding of the X-ray characteristics of this class of sources, much of the original questions on the global X-ray properties of early-type galaxies remain. One in particular: how can we predict how much gas is there in any given galaxy? We have learned that the individual sources are tightly linked to the stellar component, both field stars and relative frequency of globular clusters. We have also learned that the central group galaxies, brighter and more extended, might represent a specific class of early-type galaxies, rather than the population as a whole. Yet we have not learned how to predict, from the stellar properties, how much hot gas a galaxy will have. Even a well selected class of sources, namely early type galaxies in isolation, where we can exclude the influence of the environment, appear to retain different amounts of the hot ISM produced by the stellar population, and display a wide range of Lx for their gaseous component for a relative narrow range of Lb, or mass [measured through LK], as shown by Fig. 1.

scholarly journals Recent Developments in Liposome-Based Veterinary Therapeutics

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Hassan Sadozai ◽  
Dorsa Saeidi
Keyword(s):  
Veterinary Medicine ◽  
Research Interest ◽  
Circulation Time ◽  
Phospholipid Vesicles ◽  
Future Directions ◽  
Ongoing Research ◽  
The Past ◽  
Wide Range ◽  
Recent Developments

Recent advances in nanomedicine have been studied in the veterinary field and have found a wide variety of applications. The past decade has witnessed a massive surge of research interest in liposomes for delivery of therapeutic substances in animals. Liposomes are nanosized phospholipid vesicles that can serve as delivery platforms for a wide range of substances. Liposomes are easily formulated, highly modifiable, and easily administered delivery platforms. They are biodegradable and nontoxic and have long in vivo circulation time. This review focuses on recent and ongoing research that may have relevance for veterinary medicine. By examining the recent developments in liposome-based therapeutics in animal cancers, vaccines, and analgesia, this review depicts the current significance and future directions of liposome-based delivery in veterinary medicine.

scholarly journals Ultra-Compact Dwarf Galaxies – More Massive than Allowed?

2007 ◽  
Vol 3 (S246) ◽  
pp. 427-428 ◽  
Author(s):  
Michael Hilker ◽  
S. Mieske ◽  
H. Baumgardt ◽  
J. Dabringhausen
Keyword(s):  
Globular Clusters ◽  
Stellar Population ◽  
Velocity Dispersion ◽  
Dwarf Galaxies ◽  
Population Models ◽  
High Mass ◽  
Early Type ◽  
Dynamical Mass ◽  
Dispersion Diagram

AbstractDynamical mass estimates of ultra-compact dwarfs galaxies and massive globular clusters in the Fornax and Virgo clusters and around the giant elliptical Cen A have revealed some surprising results: 1) above ~106M⊙ the mass-to-light (M/L) ratio increases with the objects' mass; 2) some UCDs/massive GCs show high M/L values (4 to 6) that are not compatible with standard stellar population models; and 3) in the luminosity-velocity dispersion diagram, UCDs deviate from the well-defined relation of “normal” GCs, being more in line with the Faber-Jackson relation of early-type galaxies. In this contribution, we present the observational evidences for high mass-to-light ratios of UCDs and discuss possible explanations for them.

scholarly journals Radiation driven planar foil instability and mix experiments at the AWE HELEN laser

1990 ◽  
Vol 8 (1-2) ◽  
pp. 51-71 ◽  
Author(s):  
J. C. V. Hansom ◽  
P. A. Rosen ◽  
T. J. Goldack ◽  
K. Oades ◽  
P. Fieldhouse ◽  
...  
Keyword(s):  
Spectral Absorption ◽  
Parylene C ◽  
One Dimensional ◽  
The Past ◽  
First Results ◽  
Recent Developments ◽  
Full Analysis ◽  
Point Projection ◽  
Absorption Features ◽  
Made In

This paper reviews recent developments and achievements in the program of planar foil instability experiments being performed at the AWE HELEN laser. Point projection Xray backlighting, with spectroscopy, is used to measure hydrodynamic mix in radiatively accelerated ablator/foil packages; the mix is identified in the experimental radiograph from the overlap of distinguishable spectral absorption features associated with each of the constituent materials.The first part of the paper describes the backlighting technique, and briefly summarizes progress made in the past two years, leading to the first results being obtained on a “high mix” Parylene-C ablator/molybdenum payload package. The second part considers the full analysis of one such ‘high mix’ shot (Shot 7772), describing how the spatial distribution of mix has been quantified and considering the various sources of error. Comparisons are made with both one-dimensional and two-dimensional hydrocode simulations. Finally, various improvements and extensions to the experiment and codes are indicated.

scholarly journals Stellar Population and Elemental Abundance Gradients of Early-type Galaxies*

2021 ◽  
Vol 923 (1) ◽  
pp. 65
Author(s):  
A. Feldmeier-Krause ◽  
I. Lonoce ◽  
W. L. Freedman
Keyword(s):  
Stellar Population ◽  
Stellar Populations ◽  
Initial Mass Function ◽  
Elemental Abundance ◽  
Early Type ◽  
Elemental Abundances ◽  
Global Correlation ◽  
Wide Range ◽  
Local Correlations ◽  
The Imf

Abstract The evolution of galaxies is imprinted on their stellar populations. Several stellar population properties in massive early-type galaxies have been shown to correlate with intrinsic galaxy properties such as the galaxy’s central velocity dispersion, suggesting that stars formed in an initial collapse of gas (z ∼ 2). However, stellar populations change as a function of galaxy radius, and it is not clear how local gradients of individual galaxies are influenced by global galaxy properties and galaxy environment. In this paper, we study the stellar populations of eight early-type galaxies as a function of radius. We use optical spectroscopy (∼4000–8600 Å) and full spectral fitting to measure stellar population age, metallicity, slope of the initial mass function (IMF), and nine elemental abundances (O, Mg, Si, Ca, Ti, C, N, Na, and Fe) out to 1 R e for each galaxy individually. We find a wide range of properties, with ages ranging from 3–13 Gyr. Some galaxies have a radially constant, Salpeter-like IMF, and other galaxies have a super-Salpeter IMF in the center, decreasing to a sub-Salpeter IMF at ∼0.5 R e . We find a global correlation of the central [Z/H] with the central IMF and the radial gradient of the IMF for the eight galaxies, but local correlations of the IMF slope with other stellar population parameters hold only for subsets of the galaxies in our sample. Some elemental abundances also correlate locally with each other within a galaxy, suggesting a common production channel. These local correlations appear only in subsets of our galaxies, indicating variations of the stellar content among different galaxies.

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