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Related papers: Stroemgren metallicity calibration: the m1, b-y re…

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We present wide field JHKs photometry of 16 Galactic globular clusters located towards the Galactic bulge, calibrated on the 2MASS photometric system. Differential reddening corrections and statistical field star decontamination are…

Solar and Stellar Astrophysics · Physics 2016-11-15 Roger E. Cohen , Christian Moni Bidin , Francesco Mauro , Charles Bonatto , Douglas Geisler

Clusters of galaxies allow a direct estimate of the metallicity and metal production yield on the largest scale so far. The ratio of the total iron mass in the ICM to the total optical luminosity of the cluster (the iron…

Astrophysics · Physics 2007-05-23 Alvio Renzini

The near-infrared Calcium II Triplet (CaT), around 850nm, is a key metallicity indicator for red giant stars. We present a revised [Fe/H] calibration as a function of CaT line strengths and four luminosity indicators, including the $Gaia$…

Solar and Stellar Astrophysics · Physics 2026-02-04 M. Navabi , R. Carrera , N. E. D. Noël , C. Gallart , E. Pancino , M. De Leo

Variations of ~0.4 mag are expected in the I-band absolute magnitude of red clump giants, M_I^RC, as a function of both stellar age and metallicity. This regardless of some potential theoretical uncertainties. Due to the quite large…

Astrophysics · Physics 2007-05-23 Leo Girardi

The colour and luminosity distributions of red galaxies in the cluster Abell 1185 (z=0.0325) were studied down to M*+8 in the B, V and R bands. The colour-magnitude (hereafter CM) relation is linear without evidence for a significant…

Astrophysics · Physics 2009-11-11 S. Andreon , J. -C. Cuillandre , E. Puddu , Y. Mellier

We present an empirical method to derive photometric metallicity, reddening and distance to old stellar populations by using a few major features of the Red Giant Branch (RGB) in near IR color magnitude diagrams. We combine the observed RGB…

Astrophysics · Physics 2008-11-26 F. R. Ferraro , E. Valenti , L. Origlia

We use the Stetson, HST, and Gaia DR3 data sets for 22 Galactic globular clusters to select their members and fit their CMDs with isochrones from DSED and BaSTI for $[\alpha/$Fe$]=+0.4$ and an adopted helium mass fraction $Y$. As a result,…

Astrophysics of Galaxies · Physics 2026-05-28 G. A. Gontcharov , O. S. Ryutina , C. J. Bonatto , S. S. Savchenko , S. V. Troitsky

We are using full spectrum fitting to determine the ages and metallicities of Galactic clusters (M67 and globular clusters). We find that the method is very accurate to measure the metallicity. Blue horizontal branches are well identified…

Astrophysics · Physics 2009-11-13 Mina Koleva , Philippe Prugniel , Pierre Ocvirk , Damien Le Borgne

We present metallicity and photometric parallax calibrations for the F and G type dwarfs with photometric, astrometric and spectroscopic data. The sample consists of 168 dwarf stars covering the colour, iron abundance and absolute magnitude…

Astrophysics of Galaxies · Physics 2016-06-15 S. Tuncel Guctekin , S. Bilir , S. Karaali , S. Ak , T. Ak , Z. F. Bostanci

We present metallicity dependent transformation equations between UBV and SDSS ugr colours for red giants with synthetic data. The ranges of the colours used for the transformations are 0.400 $\leq(B-V)_{0}\leq$ 1.460, -0.085$\leq(U -…

Solar and Stellar Astrophysics · Physics 2015-06-16 Salih Karaali , Esma Yaz Gökçe

The mass-luminosity relation for late-type stars has long been a critical tool for estimating stellar masses. However, there is growing need for both a higher-precision relation and a better understanding of systematic effects (e.g.,…

Aims. We use the spectra of more than 30,000 red giant branch (RGB) stars in 25 globular clusters (GC), obtained within the MUSE survey of Galactic globular clusters, to calibrate the Ca II triplet (CaT) metallicity relation and derive…

We use the most homogeneous $Geneva$ seven-colour photometric system to derive new metallicity calibrations for early A- to K-type stars that cover both, dwarf stars and giants. The calibrations are based on several spectroscopic data sets…

Solar and Stellar Astrophysics · Physics 2017-06-21 Martin Netopil

We have obtained metallicities of ~ 360 red giant stars distributed in 15 Small Magellanic Cloud (SMC) fields from near-infrared spectra covering the CaII triplet lines using the VLT + FORS2. The errors of the derived [Fe/H] values range…

Solar and Stellar Astrophysics · Physics 2015-05-14 M. C. Parisi , D. Geisler , A. J. Grocholski , J. J. Claria , A. Sarajedini

In an era of extensive photometric observations, the catalogs of RR Lyr type variable stars number tens of thousands of objects. The relation between the iron abundance [Fe/H] and the Fourier parameters of the stars light curve allows us to…

We present results from the largest CaII triplet line metallicity study of Small Magellanic Cloud (SMC) field red giant stars to date, involving 3037 objects spread across approximately 37.5 sq. deg., centred on this galaxy. We find a…

Astrophysics of Galaxies · Physics 2015-06-19 P. D. Dobbie , A. A. Cole , A. Subramaniam , S. Keller

In this contribution, results from CCD vby Stroemgren photometry of a statistically complete sample of red giants and stars in the main sequence turn-off region in omega Centauri are presented. From the location of stars in the (b-y),m_1…

Astrophysics · Physics 2007-05-23 Michael Hilker , Tom Richtler

We demonstrate how the metallicities of young super star clusters can be measured using novel spectroscopic techniques in the J-band. The near-infrared flux of super star clusters older than ~6 Myr is dominated by tens to hundreds of red…

We derive a new relation between the metallicity of Seyfert 2 Active Galactic Nuclei (AGNs) and the intensity of the narrow emission-lines ratio $N2O2$=log([N II]$\lambda$6584/[O II]$\lambda$3727). The calibration of this relation was…

Astrophysics of Galaxies · Physics 2017-02-01 C. S. Castro , O. L. Dors , M. V. Cardaci , G. F. Hagele

We present deep CCD photometry of the globular cluster M13 (NGC 6205) in the Stromgren uvby-Beta system, and determine a foreground reddening of E(b-y)= 0.015mag. From a fit to the main-sequence of metal-poor subdwarfs with Hipparcos…

Astrophysics · Physics 2009-10-30 Frank Grundahl , Don A. VandenBerg , Michael I. Andersen
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