MEGARA恒星光谱库：第二版发布
MEGARA Stellar Spectral Library. Second Release
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中文总结 AI 辅助
本文发布MEGASTAR DR2恒星光谱库，含2838条高分辨率光谱，可用于演化合成模型构建及恒星星团、星系模拟等研究。
中文摘要 AI 辅助
本文介绍MEGARA光谱库的第二版——MEGASTAR，该版本包含在Gran Telescopio CANARIAS望远镜的十个观测学期内采集的所有光谱。此新版本取代了第一版，新增了2000条高光谱分辨率（R(FWHM)≈20000）的观测数据，覆盖两个波长范围：以Hα为中心的6420-6790埃和以CaII三重线为中心的8370-8885埃。本文旨在向学界推出MEGASTAR DR2，其高分辨率光谱可作为多种研究的宝贵资源，尤其将用于在HR-PyPopStar演化合成模型中构建SSP块。恒星通过仪器的积分场光谱模式观测，数据采用MEGARA数据处理流水线进行统一处理。研究人员通过对积分场单元（IFU）重构图像中流量最高的空间像素（spaxel）为中心的37个空间像素的光谱求和来估计恒星光度，该方法确保所有光谱的有效狭缝宽度及光谱分辨率一致。第二版MEGASTAR共包含对应1408颗恒星的2838条光谱，相比第一版更好地覆盖了恒星参数空间，光谱的平均连续谱信噪比约为215。此第二版符合现代经验光谱库的标准：提供可靠校准、无狭缝效应的数据、大量恒星的观测，以及用于模拟MEGARA观测的单个恒星星团和整个星系的高光谱分辨率。
英文摘要
We present the second release of the MEGARA spectral library, MEGASTAR, which now includes all spectra collected during ten observing semesters at the Gran Telescopio CANARIAS. This new release supersedes our first release and incorporates a substantial number of additional observations (2000 new spectra), obtained at high spectral resolution, R(FWHM)$\sim$20000, in two wavelength ranges centred on H$α$ (6420 - 6790 A) and on the CaII triplet (8370 - 8885 A). The aim of this paper is to introduce MEGASTAR DR2 to the community as its high-resolution spectra can serve as a valuable resource for numerous types of research. In particular, we will use MEGASTAR spectra to construct SSP blocks within the HR-PyPopStar evolutionary synthesis models. The stars were observed using the integral field spectroscopy mode of the instrument. We process the data in a uniform way with the MEGARA data reduction pipeline. We estimate the stellar flux by adding the spectra from 37 spaxels, centred on the spaxel with the highest flux in the IFU reconstructed image. This approach guarantees that the effective slit width, and therefore the spectral resolution, are the same for all spectra. The second MEGASTAR release consists of 2838 spectra corresponding to 1408 stars, providing a better coverage of the stellar parameter space than the first release. The spectra were acquired with an average continuum S/N of about 215. This second release meets the standards of a modern empirical library: it offers reliable calibrations, data free from slit effects, observations of a large number of stars, and provides high spectral resolution to model both individual stellar clusters and entire galaxies observed with MEGARA.
发表机构
- Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE)（墨西哥国家天体物理学、光学和电子学研究所）
- FRACTAL S.L.N.E.
- Universidad Complutense de Madrid（马德里康普顿斯大学）
- Centro de Astrobiología (CSIC-INTA)（天体生物学中心（西班牙国家研究委员会-国家航空航天技术研究所））
- Universidad de La Laguna（拉古纳大学）
- Instituto de Astrofísica de Canarias（加那利群岛天体物理研究所）
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