Análisis de los índices de Lick en el cúmulo de Coma

SCALIA, M. C.; SMITH CASTELLI, A.; FAIFER, F.

Congreso; 64 Reunión Anual de la Asociación Argentina de Astronomía; 2022

We present here the analysis of the color-magnitude relation (CMR) or red sequence (RS) of the Coma cluster, by obtaining the Lick indices. The CMR or RS is a photometric relation that has been analyzed and discussed for more than 60 years. It is known that it mainly represents a mass-metallicity relationship and that it also shows similar slopes and dispersions in different environments. However, it is still unknown how the different chemical species contribute to the definition and location of each galaxy in this relation. In previous work, we have found that in the Virgo cluster there seems to be some degree of color (g-z) dependence on some of the above indices, a dependence that is not detected in a sample of early-type galaxies located in the Stripe-82 region of the sky. We wonder if the detection of such dependencies in the Virgo cluster and not in the Stripe-82 region would indicate that they originate from environmental effects. To try to answer this question, we analyzed a sample of 154 galaxies belonging to the Coma cluster, through their spectra obtained from the Sloan Digital Sky Survey (SDSS) database. We find that the behavior of these indices for the Coma Cluster sample is similar to that of the Virgo Cluster, but extended towards higher luminosities, indicating similar dependencies in cluster environments.