Uma Biblioteca de Espectros Estelares no Infravermelho Próximo para Medidas de Cinemática Estelar em Galáxias

Marlon R. Diniz, Rogemar A. Riffel


In this work, we have expanded the library in the K-band spectra of thelate-type stars in the Gemini observatory through the observationsobtained with the Near-infrared Integral Field Spectrograph (NIFS),available in the Gemini archive. The main application of this library isthe measurement of stellar kinematics in galaxies by the fitting of theCO band heads at ~ 2.3 mm. To obtain reliable measurements of velocitydispersion ( !*) it is necessary to include different spectral types,representative of the stellar population which produces such absorptions.We present spectra of 20 stars with spectral resolution of ~ 3.2 Å,including 11 K stars, 8 M and 1 of the type G, representing an increase of50%. The inclusion of eight spectra of M-type stars has a fundamentalimportance because such stars were absent the original library. Thisinclusion allows more robust measurements for the stellar !* in galaxies.We present plots of equivalent width (EW) for CaIl 2.2636m m,FeIl 2.2387l m, NaIl 2.2070m m, 12COl 2.2935m m, 13COl 2.3448mmand MgIl 2.2814m m versus the effective temperature (Teff ) of the star.These plots show that stars with lower Teff have greater values of EW forthe first five lines. While for MgIl 2.2814m m, the EW has a constantvalue of ~ 0.6 Å for stars of different temperatures. Finally, the use ofthe expanded library will provide more reliable measurements of stellarkinematics in the galaxies.


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