The Gemini spectral library of near-IR late type stellar templates and its application for velocity dispersion measurements

TL;DR

This paper introduces a high-resolution near-IR spectral library of late-type stars designed to improve stellar kinematic measurements in galaxies, aiding supermassive black hole mass estimations.

Contribution

It provides a new spectral library tailored for near-IR stellar kinematics, supporting more accurate velocity dispersion measurements with modern spectrographs.

Findings

The library enhances the analysis of circumnuclear stellar kinematics.

It allows assessment of the 'template mismatch' effect on velocity dispersion.

The templates are adaptable for various near-IR spectrographs.

Abstract

We present a spectroscopic library of late spectral type stellar templates in the near-IR range 2.15-2.42microns, at R=5300-5900 resolution, oriented to support stellar kinematics studies in external galaxies, such as the direct determination of the masses of supermassive black-holes in nearby active (or non-active) galaxies. The combination of high spectral resolution and state-of-the-art instrumentation available in 8-m class telescopes has made the analysis of circumnuclear stellar kinematics using the near-IR CO band heads one of the most used techniques for such studies, and this library aims to provide the supporting datasets required by the higher spectral resolution and larger spectral coverage currently achieved with modern near-IR spectrographs. Examples of the application for kinematical analysis are given for data obtained with two Gemini instruments, but the templates can be easily adjusted for use with other near-IR spectrographs at similar or lower resolution. The example datasets are also used to revisit the "template mismatch" effect and the dependence of the velocity dispersion values obtained from the fitting process with the characteristics of the stellar templates. The library is available in electronic form from the Gemini web pages (link above).