Seyfert's Sextet: A Slowly Dissolving Stephan's Quintet - AstrophysicsReportar como inadecuado

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Abstract: We present a multiwavelength study of the highly evolved compact galaxy groupknown as Seyfert-s Sextet HCG79: SS. We interpret SS as a 2-3 Gyr moreevolved analog of Stephan-s Quintet HCG92: SQ. We postulate that SS formed bysequential acquisition of 4-5 primarily late-type field galaxies. Four of thefive galaxies show an early-type morphology which is likely the result ofsecular evolution driven by gas stripping. Stellar stripping has produced amassive-luminous halo and embedded galaxies that are overluminous for theirsize. These are interpreted as remnant bulges of the accreted spirals. H79dcould be interpreted as the most recent intruder being the only galaxy with anintact ISM and uncertain evidence for tidal perturbation. In addition tostripping activity we find evidence for past accretion events. H79b NGC6027shows a strong counter-rotating emission line component interpreted as anaccreted dwarf spiral. H79a shows evidence for an infalling component of gasrepresenting feedback or possible cross fueling by H79d. The biggest challengeto this scenario involves the low gas fraction in the group. If SS formed fromnormal field spirals then much of the gas is missing. Finally, despite itsadvanced stage of evolution, we find no evidence for major mergers and inferthat SS and SQ are telling us that such groups coalesce via slow dissolution.

Autor: A. Durbala, A. del Olmo, M. S. Yun, M. Rosado, J. W. Sulentic, H. Plana, A. Iovino, J. Perea, L. Verdes-Montenegro, I. Fuentes-Ca


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