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Evolutionary trends in the surface abundances of heavier elements have recently been identified in the globular cluster NGC 6397 ([Fe/H]=-2), indicating the operation of atomic diffusion in these stars. Such trends constitute important…

Astrophysics · Physics 2009-11-13 K. Lind , A. J. Korn , P. S. Barklem , F. Grundahl

We present mean horizontal branch absolute magnitudes and iron abundances for a sample of 39 globular clusters. These quantities were calculated in an unprecedented homogeneous fashion based on Fourier decomposition of ligt curves of RR…

Solar and Stellar Astrophysics · Physics 2023-06-05 Armando Arellano Ferro

Intrinsic iron abundance spreads in globular clusters, although usually small, are very common, and are signatures of self enrichment: some stars within the cluster have been enriched by supernova ejecta from other stars within the same…

Astrophysics of Galaxies · Physics 2022-02-02 Jeremy Bailin , Ryker von Klar

In this paper, we aim to derive high-precision alpha-element abundances using CRIRES high-resolution IR spectra of 72 cool M giants of the inner Galactic bulge. Silicon, magnesium, and calcium abundances were determined by fitting a…

Astrophysics of Galaxies · Physics 2023-03-08 N. Nieuwmunster , G. Nandakumar , E. Spitoni , N. Ryde , M. Schultheis , R. M. Rich , P. S. Barklem , O. Agertz , F. Renaud , F. Matteucci

We study the relationship between the iron abundance (IA) in red giant branch (RGB) stars and their radial distribution (RD) in Galactic globular clusters (GCs). We relied on publicly available archival data on IA in red giants (RGs) of…

Astrophysics of Galaxies · Physics 2013-06-21 Valery V. Kravtsov

Differential abundances of C, O, Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, and Zr were determined from high signal-to-noise VLT/UVES spectra for 25 turnoff stars with -2.4 < [Fe/H] < -1.3. Effective temperatures were obtained from…

Astrophysics of Galaxies · Physics 2026-05-01 Poul Erik Nissen , Anish Amarsi

A set of 76 open clusters with abundances based upon DDO photometry and/or moderate dispersion spectroscopy has been transformed to a common [Fe/H] scale and used to study the local structure and evolution of the galactic disk. The…

Astrophysics · Physics 2009-10-30 Bruce A. Twarog , Keith M. Ashman , Barbara J. Anthony-Twarog

We have performed a detailed spectral analysis of the inner halo Galactic globular cluster (GC) NGC 6723 using high resolution (R$\approx$ 22000-48000) spectra for for eleven red giant branch stars collected with MIKE (Magellan) and FEROS…

Solar and Stellar Astrophysics · Physics 2019-07-10 Juliana Crestani , Alan Alves-Brito , Giuseppe Bono , Arthur A. Puls , Javier Alonso-García

We have obtained medium-resolution infrared K band spectra of 44 giants in seven heavily reddened clusters in the Galactic bulge, as well as 12 giants in omega Centauri. We measure the equivalent widths of the Na doublet, the Ca triplet,…

Astrophysics · Physics 2009-11-10 Andrew W. Stephens , Jay A. Frogel

The metallicity spread, or the metallicity trend along the evolutionary sequence of a globular cluster, is a rich source of information to help understand the cluster physics (e.g. multiple populations) and stellar physics (e.g. atomic…

Solar and Stellar Astrophysics · Physics 2022-05-25 Martina Baratella , Deepthi S. Prabhu , Luiz A. Silva-Lima , Philippe Prugniel

We estimate the empirical R parameter in 26 Galactic Globular Clusters covering a wide metallicity range, imaged by WFPC2 on board the HST. The improved spatial resolution permits a large fraction of the evolved stars to be measured and…

Astrophysics · Physics 2009-10-31 M. Zoccali , S. Cassisi , G. Bono , G. Piotto , R. M. Rich , S. G. Djorgovski

A subset of 150 globular clusters in M87 has been selected on the basis of S/N ratio for abundance and age determinations from the sample of Paper I. Indices measuring the strength of the strongest spectral features were determined for the…

Astrophysics · Physics 2009-10-30 Judith G. Cohen , John P. Blakeslee , Anton Ryzhov

We studied the distributions of metal abundances and metal-mass-to-light ratios in the intracluster medium (ICM) of four galaxy groups, MKW 4, HCG 62, the NGC 1550 group, and the NGC 5044 group, out to 0.5 r180 observed with Suzaku. The Fe…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Toru Sasaki , Kyoko Matsushita , Kosuke Sato

We explore a scenario where metal-poor globular clusters (GCs) are enriched by the first supernovae in the Universe. If the first stars in a 10^7 Msun dark halo were very massive (>180 Msun), then a pair instability supernova from a single…

Integrated spectra of Milky Way globular clusters (GCs) are reproduced by computing synthetic spectra taking into account individual element abundances. Five clusters were selected from their location in the Galactic bulge, for which…

Solar and Stellar Astrophysics · Physics 2019-11-05 Tatiana Coelho de Moura , Marina Trevisan , Beatriz Barbuy , Silvia Rossi

We report new metallicities for stars of Galactic globular cluster M4 using the largest number of stars ever observed at high spectral resolution in any cluster. We analyzed 7250 spectra for 2771 cluster stars gathered with the VLT…

Solar and Stellar Astrophysics · Physics 2015-06-17 Luca Malavolta , Christopher Sneden , Giampaolo Piotto , Antonino P. Milone , Luigi R. Bedin , Valerio Nascimbeni

We present the analysis of the X-ray spectra of 18 distant clusters of galaxies with redshift 0.3 < z < 1.3. Most of them were observed with the Chandra satellite in long exposures ranging from 36 ks to 180 ks. For two of the z>1 clusters…

Astrophysics · Physics 2009-11-07 P. Tozzi , P. Rosati , S. Ettori , S. Borgani , V. Mainieri , C. Norman

We have observed 15 red giant stars in the relatively massive, metal-poor globular cluster NGC 4833 using the Magellan Inamori Kyocera Echelle spectrograph at Magellan. We calculate stellar parameters for each star and perform a standard…

Solar and Stellar Astrophysics · Physics 2015-06-24 Ian U. Roederer , Ian B. Thompson

We investigate the spatial distribution of iron in the intra-cluster medium in a selected sample of 41 relaxed clusters in the redshift range $0.05 < z < 1.03$ using {\sl Chandra} archival data. We compute the azimuthally-averaged,…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-29 Ang Liu , Paolo Tozzi , Heng Yu , Sabrina De Grandi , Stefano Ettori

Understanding the spatial distribution of metals within galaxies allows us to study the processes of chemical enrichment and mixing in the interstellar medium (ISM). In this work, we map the two-dimensional distribution of metals using a…