MEGARA-GTC Stellar Spectral Library (II). MEGASTAR First Release

TL;DR

This paper introduces the first release of the MEGASTAR spectral library, comprising high-resolution spectra of 414 stars observed with the MEGARA instrument at GTC, essential for interpreting MEGARA data.

Contribution

It provides the initial version of an empirical stellar spectral library from MEGARA-GTC observations, including data, reduction procedures, and an atlas of spectra.

Findings

Spectra of 414 stars included in the first release.

Spectral resolution around R ≈ 20000.

High signal-to-noise ratio averaging 260.

Abstract

MEGARA is an optical integral field and multiobject fibre based spectrograph for the 10.4m Gran Telescopio CANARIAS that offers medium to high spectral resolutions (FWHM) of R $\simeq$ 6000, 12000, 20000. Commissioned at the telescope in 2017, it started operation as a common-user instrument in 2018. We are creating an instrument-oriented empirical spectral library from MEGARA-GTC stars observations, MEGASTAR, crucial for the correct interpretation of MEGARA data. This piece of work describes the content of the first release of MEGASTAR, formed by the spectra of 414 stars observed with R $\simeq$ 20000 in the spectral intervals from 6420 to 6790 $\r{A}$ and from 8370 to 8885 $\r{A}$, and obtained with a continuum average signal to noise ratio around 260. We describe the release sample, the observations, the data reduction procedure and the MEGASTAR database. Additionally, we include in Appendix A, an atlas with the complete set of 838 spectra of this first release of the MEGASTAR catalogue.