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The metallicity distribution function of globular clusters (GCs) in galaxies is a key to understanding galactic formation and evolution. The calcium II triplet (CaT) index has recently become a popular metal abundance indicator thanks to…

Astrophysics of Galaxies · Physics 2016-03-16 Chul Chung , Suk-Jin Yoon , Sang-Yoon Lee , Young-Wook Lee

Measurements of [C/Fe], [Ca/H], and [Fe/H] have been derived from Keck I LRISb spectra of 35 giants in the Draco dwarf spheroidal galaxy. The iron abundances are derived by a spectrum synthesis modeling of the wavelength region from 4850 to…

Astrophysics of Galaxies · Physics 2013-03-14 Matthew D. Shetrone , Graeme H. Smith , Laura M. Stanford , Michael H. Siegel , Howard E. Bond

While the Milky Way Nuclear star cluster has been studied extensively, how it formed is uncertain. Studies have shown it contains a solar and supersolar metallicity population that may have formed in-situ, along with a subsolar metallicity…

Astrophysics of Galaxies · Physics 2022-02-02 Rory O. Bentley , Tuan Do , Wolfgang Kerzendorf , Devin S. Chu , Zhuo Chen , Quinn Konopacky , Andrea Ghez

Assuming that in the atmospheres of low-mass, metal-poor red giant stars, 1-D models based on LTE accurately predict the abundance of iron from Fe II, we derive a globular cluster metallicity scale based on the equivalent widths of Fe II…

Astrophysics · Physics 2009-07-28 Robert P. Kraft , Inese I. Ivans

Using a near-IR stellar library of 706 stars with a wide coverage of atmospheric parameters, we study the behaviour of the Ca II triplet strength in terms of effective temperature, surface gravity and metallicity. Empirical fitting…

Astrophysics · Physics 2009-11-07 A. J. Cenarro , J. Gorgas , N. Cardiel , A. Vazdekis , R. F. Peletier

Based on a carefully constructed sample of dwarf stars, a new optical-near infrared photometric calibration to estimate the metallicity of late-type K and early-to-mid-type M dwarfs is presented. The calibration sample has two parts; the…

Solar and Stellar Astrophysics · Physics 2015-06-24 Neda Hejazi , Michael M. De Robertis , Peter C. Dawson

A search for lithium is performed on seven metal poor dwarfs with metallicities ranging from [Fe/H]=-1.5 down to [Fe/H]=-3.0 but showing disk-like kinematics. These stars belong to the metal poor tail of the Galactic thick disk and they may…

Astrophysics · Physics 2016-01-13 P. Molaro , P. Bonifacio , L. Pasquini

We present measurements of the pseudo-equivalent width of the Fe II,$\lambda$5018 absorption feature in the spectra of 12 Type IIP supernovae (SNe II) in low luminosity ($M>-17$) dwarf host galaxies. The Fe II,$\lambda$5018 line has been…

Solar and Stellar Astrophysics · Physics 2019-01-16 Spencer Scott , Matt Nicholl , Peter Blanchard , Sebastian Gomez , Edo Berger

It is debated whether the Milky Way bulge has the characteristics of a classical bulge sooner than those of a pseudobulge. Detailed abundance studies of bulge stars is a key to investigate the origin, history, and classification of the…

We present the abundances of Li, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Zn, Sr, Y, Zr, and Ba in a wide metallicity range ($-2.8 \le$ [Fe/H] $\le -1.5$). Using the differential technique allowed us to obtain an unprecedented low…

Solar and Stellar Astrophysics · Physics 2017-12-06 Henrique Reggiani , Jorge Meléndez , Chiaki Kobayashi , Amanda Karakas , Vinicius Placco

Photospheric abundances of C, N, O, and Na were determined by applying the synthetic spectrum-fitting technique to 34 snap-shot high-dispersion spectra of 22 RR Lyr stars covering a metallicity range of -1.8 <[Fe/H] < 0.0, with an aim of…

Solar and Stellar Astrophysics · Physics 2022-06-29 Yoichi Takeda

We investigate the intrinsic scatter in the chemical abundances of a sample of metal-poor ([Fe/H]<-2.5) Milky Way halo stars. We draw our sample from four historic surveys and focus our attention on the stellar Mg, Ca, Ni, and Fe…

Astrophysics of Galaxies · Physics 2020-11-04 Louise Welsh , Ryan Cooke , Michele Fumagalli

We briefly describe our on-going investigation of the near-IR luminosity-metallicity relationship for dwarf irregular galaxies in nearby groups of galaxies. The motivations of the project and the observational databases are introduced, and…

Astrophysics · Physics 2007-05-23 Ivo Saviane , R. Riegerbauer , E. V. Held , V. Ivanov , D. Alloin , F. Bresolin , Y. Momany , R. M. Rich , L. Rizzi

We present a low metallicity map of the Milky Way consisting of $\sim$111,000 giants with $-3.5 \lesssim$ [Fe/H] $\lesssim -$0.75, based on public photometry from the second data release of the SkyMapper survey. These stars extend out to…

Astrophysics of Galaxies · Physics 2021-04-28 Anirudh Chiti , Mohammad K. Mardini , Anna Frebel , Tatsuya Daniel

We present chemical abundances derived from high-resolution Magellan/MIKE spectra of the nine brightest known red giant members of the ultra-faint dwarf galaxy Reticulum II. These stars span the full metallicity range of Ret II (-3.5 <…

Astrophysics of Galaxies · Physics 2016-10-26 Alexander P. Ji , Anna Frebel , Joshua D. Simon , Anirudh Chiti

Through a homogeneous analysis of spectroscopic literature data of red giant stars, we determine the radial metallicity profiles of 30 dwarf galaxies in the Local Group. We explore correlations between the calculated metallicity gradients…

Astrophysics of Galaxies · Physics 2022-09-14 S. Taibi , G. Battaglia , R. Leaman , A. Brooks , C. Riggs , F. Munshi , Y. Revaz , P. Jablonka

Deriving the metallicity, [Fe/H], in low-resolution spectra of carbon-enhanced metal-poor (CEMP) stars is a tedious task that, owing to the large number of line blends, often leads to uncertainties on [Fe/H] exceeding 0.25dex. The CEMP…

Solar and Stellar Astrophysics · Physics 2020-02-12 D. Singh , C. J. Hansen , J. S. Byrgesen , M. Reichert , H. M. Reggiani

We demonstrate that low resolution CaII triplet (CaT) spectroscopic estimates of the overall metallicity ([Fe/H]) of individual Red Giant Branch (RGB) stars in two nearby dwarf spheroidal galaxies (dSphs) agree to +-0.1-0.2 dex with…

Astrophysics · Physics 2009-11-13 G. Battaglia , M. Irwin , E. Tolstoy , V. Hill , A. Helmi , B. Letarte , P. Jablonka

We studied a sample of high proper motion, old and metal-rich dwarf stars, selected from the NLTT catalogue. The low pericentric distances and eccentric orbits of these solar neighbourhood stars indicate that they might have originated in…

Solar and Stellar Astrophysics · Physics 2014-10-15 M. Trevisan , B. Barbuy

Star-forming dwarf galaxies in the local Universe, especially extremely metal-poor ones, can be considered analogous to early galaxies of the Epoch of Reionization (z >= 6). Currently available telescopes cannot adequately detect and…