相关论文: Panchromatic calibration of Ca II triplet luminosi…

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 $Gaia$…

Context. [...] One of the most efficient methods is the measurement of the equivalent width (EW) of the Calcium II Triplet (CaT), corrected for the luminosity and temperature effects via magnitude differences from the horizontal branch…

Measurements are presented and analyzed of the strength of the Ca II triplet lines in red giants in Galactic globular and open clusters, and in a sample of red giants in the LMC disk that have significantly different [Ca/Fe] abundance…

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…

How can we accurately determine the metallicity of faint red giant stars in nearby galaxies? The equivalent widths of the broad absorption lines from Ca II at 8498, 8542, and 8662 Angstrom (the calcium triplet) have shown a smooth…

Medium resolution (R=4,000 to 9,000) spectra of the near infrared Ca II lines (at 8498, 8542, and 8662 A) in M31 globular cluster integrated light spectra are presented. In individual stars the Ca II triplet (CaT) traces stellar…

We extend our previous calibration of the infrared Ca II triplet as metallicity indicator to the metal-poor regime by including observations of 55 field stars with [Fe/H] down to -4.0 dex. While we previously solved the saturation at…

We present a new calibration of the Calcium II Triplet equivalent widths versus [Fe/H], constructed upon K giant stars in the Galactic bulge. This calibration will be used to derive iron abundances for the targets of the GIBS survey, and in…

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…

Using data from the WiFeS Atlas of Galactic Globular cluster Spectra we study the behaviour of the calcium triplet (CaT), a popular metallicity indicator in extragalactic stellar population studies. A major caveat of these studies is that…

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…

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…

The Ca triplet (CaT) feature in the near-infrared has been employed as a metallicity indicator for individual stars as well as integrated light of Galactic globular clusters (GCs) and galaxies with varying degrees of success, and sometimes…

From observations of almost 500 RGB stars in 29 Galactic open and globular clusters, we have investigated the behaviour of the infrared Ca II triplet (8498, 8542 and 8662 \AA) in the age range 13$\leq$Age/Gyr$\leq$0.25 and the metallicity…

We present theoretical equivalent widths for the sum of the two strongest lines of the Calcium Triplet, CaT index, in the near-IR, using evolutionary techniques and the most recent models and observational data for this feature in…

Modelling the low ionization lines (LIL) in active galactic nuclei still faces problems in explaining the observed equivalent widths (EWs). We examine the optical Fe II and near-infrared Ca II triplet (CaT) emission strengths using the…

The Ca~II H \& K lines are among the few features available to infer the metallicity of extremely metal-poor stars from medium-resolution spectroscopy. Unfortunately, these lines can overlap with absorption produced in the intervening…

We describe a new spectroscopic technique for measuring radial metallicity gradients out to large galactocentric radii. We use the DEIMOS multi-object spectrograph on the Keck telescope and the galaxy spectrum extraction technique of…

The NIR Ca II triplet absorption lines have proven to be an important tool for quantitative spectroscopy of individual red giant branch stars in the Local Group, providing a better understanding of metallicities of stars in the Milky Way…

The serendipitous discovery of the M31 globular cluster (GC) EXT8 has presented a significant challenge to current theories for GC formation. By finding other GCs similar to EXT8, it should become clear if and/or how EXT8 can fit into our…