scholarly journals Chemical abundances of globular clusters in NGC 5128 (Centaurus A)

2018 ◽  
Vol 476 (4) ◽  
pp. 5189-5215 ◽  
Author(s):  
Svea Hernandez ◽  
Søren Larsen ◽  
Scott Trager ◽  
Lex Kaper ◽  
Paul Groot
Keyword(s):  
Globular Clusters ◽  
Chemical Abundances ◽  
Centaurus A

scholarly journals Chemical Abundances of Seven Outer Halo M31 Globular Clusters from the Pan-Andromeda Archaeological Survey

2016 ◽  
Vol 11 (S321) ◽  
pp. 10-12
Author(s):  
Charli M. Sakari
Keyword(s):  
Globular Clusters ◽  
Milky Way ◽  
Dwarf Galaxy ◽  
Large Magellanic Cloud ◽  
Archaeological Survey ◽  
Chemical Abundances ◽  
Light Spectra ◽  
Sigma Level ◽  
Stellar Streams ◽  
Detailed Chemical

AbstractObservations of stellar streams in M31’s outer halo suggest that M31 is actively accreting several dwarf galaxies and their globular clusters (GCs). Detailed abundances can chemically link clusters to their birth environments, establishing whether or not a GC has been accreted from a satellite dwarf galaxy. This talk presents the detailed chemical abundances of seven M31 outer halo GCs (with projected distances from M31 greater than 30 kpc), as derived from high-resolution integrated-light spectra taken with the Hobby Eberly Telescope. Five of these clusters were recently discovered in the Pan-Andromeda Archaeological Survey (PAndAS)—this talk presents the first determinations of integrated Fe, Na, Mg, Ca, Ti, Ni, Ba, and Eu abundances for these clusters. Four of the target clusters (PA06, PA53, PA54, and PA56) are metal-poor ([Fe/H] < -1.5), α-enhanced (though they are possibly less alpha-enhanced than Milky Way stars at the 1 sigma level), and show signs of star-to-star Na and Mg variations. The other three GCs (H10, H23, and PA17) are more metal-rich, with metallicities ranging from [Fe/H] = -1.4 to -0.9. While H23 is chemically similar to Milky Way field stars, Milky Way GCs, and other M31 clusters, H10 and PA17 have moderately-low [Ca/Fe], compared to Milky Way field stars and clusters. Additionally, PA17’s high [Mg/Ca] and [Ba/Eu] ratios are distinct from Milky Way stars, and are in better agreement with the stars and clusters in the Large Magellanic Cloud (LMC). None of the clusters studied here can be conclusively linked to any of the identified streams from PAndAS; however, based on their locations, kinematics, metallicities, and detailed abundances, the most metal-rich PAndAS clusters H23 and PA17 may be associated with the progenitor of the Giant Stellar Stream, H10 may be associated with the SW Cloud, and PA53 and PA56 may be associated with the Eastern Cloud.

scholarly journals Chemical abundances in tidally disrupted globular clusters

2009 ◽  
Vol 5 (S266) ◽  
pp. 157-160
Author(s):  
D. Yong ◽  
J. Meléndez ◽  
K. Cunha ◽  
A. I. Karakas ◽  
J. E. Norris ◽  
...  
Keyword(s):  
Globular Cluster ◽  
Preliminary Analysis ◽  
Globular Clusters ◽  
Building Blocks ◽  
Light Elements ◽  
Chemical Abundances ◽  
Chemical Enrichment ◽  
Abundance Variation

AbstractWe present abundance measurements in the tidally disrupted globular cluster NGC 6712. In this cluster, there are large star-to-star variations of the light elements C, N, O, F and Na. While such abundance variations are seen in every well-studied globular cluster, they are not found in field stars and indicate that clusters like NGC 6712 cannot provide many field stars and/or field stars do not form in environments with chemical-enrichment histories like those of NGC 6712. Preliminary analysis of NGC 5466, another tidally disrupted cluster, suggests little (if any) abundance variation for O and Na and the abundance ratios [X/Fe] are comparable to field stars at the same metallicity. Therefore, globular clusters like NGC 5466 may have been Galactic building blocks.

Globular Clusters Old and Young in NGC 5128 (Centaurus A)

2006 ◽  
pp. 129-132
Author(s):  
Eric W. Peng ◽  
Holland C. Ford ◽  
Kenneth C. Freeman
Keyword(s):  
Globular Clusters ◽  
Centaurus A

Chemical composition of globular clusters in dwarf galaxies

2019 ◽  
Vol 14 (S351) ◽  
pp. 317-320
Author(s):  
Søren S. Larsen
Keyword(s):  
Chemical Composition ◽  
Globular Clusters ◽  
Milky Way ◽  
Local Group ◽  
Dwarf Galaxies ◽  
Chemical Abundances ◽  
Preliminary Results ◽  
Detailed Chemical

AbstractThis contribution gives an update on on-going efforts to characterise the detailed chemical abundances of Local Group globular clusters (GCs) from integrated-light spectroscopy. Observations of a sample of 20 GCs so far, located primarily within dwarf galaxies, show that at low metallicities the [α/Fe] ratios are generally indistinguishable from those in Milky Way GCs. However, the “knee” above which [α/Fe] decreases towards Solar-scaled values occurs at lower metallicities in the dwarfs, implying that GCs follow the same trends seen in field stars. Efforts are underway to establish NLTE corrections for integrated-light abundance measurements, and preliminary results for Mn are discussed.

scholarly journals Integrated spectroscopy of extragalactic Globular Clusters

2019 ◽  
Vol 14 (S351) ◽  
pp. 155-160
Author(s):  
Charli M. Sakari
Keyword(s):  
Globular Clusters ◽  
Milky Way ◽  
Light Element ◽  
Element Abundance ◽  
Future Perspectives ◽  
Host Galaxies ◽  
Chemical Abundances ◽  
Essential Information ◽  
Light Element Abundance ◽  
Detailed Chemical

AbstractIntegrated light (IL) spectroscopy enables studies of stellar populations beyond the Milky Way and its nearest satellites. In this paper, I will review how IL spectroscopy reveals essential information about globular clusters and the assembly histories of their host galaxies, concentrating particularly on the metallicities and detailed chemical abundances of the GCs in M31. I will also briefly mention the effects of multiple populations on IL spectra, and how observations of distant globular clusters help constrain the source(s) of light-element abundance variations. I will end with future perspectives, emphasizing how IL spectroscopy can bridge the gap between Galactic and extragalactic astronomy.

scholarly journals The Chemical Abundances of the Halo Clusters of the Galaxy

1978 ◽  
Vol 80 ◽  
pp. 177-182
Author(s):  
R. Canterna ◽  
R. A. Schommer
Keyword(s):  
Globular Clusters ◽  
Broad Band ◽  
Mean Value ◽  
Red Giants ◽  
Galactocentric Distance ◽  
Chemical Abundances ◽  
Dwarf Spheroidal Galaxies ◽  
The Galaxy ◽  
Ursa Minor ◽  
Metal Abundances

Photometric metal abundances of individual red giants in eight extremely distant halo globular clusters and the Draco and Ursa Minor dwarf spheroidal galaxies have been obtained using the Washington broad-band system, C, M, T1, T2(Canterna 1976). Observations were made at the KPNO 2.1-m and CTIO 1.5-m telescopes. In Table I we list for each system the mean value of [Fe/H], the number of stars observed in each system, n, the Galactocentric distance, RGC, the intrinsic color of the giant branch at the level of the horizontal branch (HB), (B-V)o,g, and the fraction of HB stars bluer than the RR Lyrae gap, fB. Sources for unpublished color-magnitude diagram (CMD) data are: Pal 11 (Canterna and Schommer), Pal 12 (Canterna and Harris), and Ursa Minor (Schommer, Olszewski and Kunkel).

scholarly journals Twins born in different environments? Nuclei of two dSphs: isolated galaxy KKS3 and E269-66, a close neighbor of NGC5128

2015 ◽  
Vol 12 (S316) ◽  
pp. 349-350
Author(s):  
Margarita Sharina ◽  
Alexei Kniazev ◽  
Igor Karachentsev
Keyword(s):  
Globular Clusters ◽  
Massive Star ◽  
Stellar Population ◽  
Central Star ◽  
Close Neighbor ◽  
Dwarf Spheroidal Galaxies ◽  
Star Forming ◽  
Star Formation Histories ◽  
Massive Clusters ◽  
Centaurus A

AbstractWe present the results of age, metallicity and radial velocity determination for central massive globular clusters (GCs) in dwarf spheroidal galaxies: KKs3 and ESO269-66. KKS3 is a unique isolated galaxy. ESO269-66 is a close neighbor of the giant S0 Centaurus A. The results contribute to the knowledge about the origin of massive star clusters and their host dSphs. The structure and star formation histories of the two dwarf galaxies look rather similar. Both of them have experienced several star-forming events. The most recent ones occurred 1-2 Gyr ago, and most powerful bursts happened 12-14 Gyrs ago. Our analysis has shown that both GCs appear to be 1-2 Gyr younger and 0.1-0.3 dex more metal-rich than the most ancient metal-poor stars in the host dSphs. We examine signatures of multiple stellar population in the GCs using our data. Since central star-forming bursts were extended in time, the massive clusters might be considered as nuclei of the galaxies.

scholarly journals A high-spectral-resolution study of abundances and isotopic composition of BHB stars in NGC 6397 and NGC 6752

2009 ◽  
Vol 5 (S266) ◽  
pp. 421-421
Author(s):  
S. Hubrig ◽  
F. Castelli ◽  
G. De Silva ◽  
J. F. González ◽  
Y. Momany ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Main Sequence ◽  
High Spectral Resolution ◽  
Horizontal Branch ◽  
Main Sequence Stars ◽  
Chemical Abundances ◽  
Chemically Peculiar ◽  
Abundance Anomalies ◽  
Isotopic Anomalies ◽  
Resolution Study

AbstractLarge abundance anomalies have previously been detected in horizontal-branch B-type stars. We present the first high-resolution study of isotopic anomalies and chemical abundances in six horizontal-branch B-type stars in the globular clusters NGC 6397 and NGC 6752, carried out with UVES on the VLT and compare them to those observed in chemically peculiar main-sequence stars.

Chemical abundances in the globular clusters M3, M13, and NGC 6752

1980 ◽  
Vol 242 ◽  
pp. 657 ◽  
Author(s):  
R. A. Bell ◽  
R. J. Dickens
Keyword(s):  
Globular Clusters ◽  
Chemical Abundances
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