Isolated elliptical galaxies in the local Universe
Context. We have studied a sample of 89 very isolated, elliptical galaxies at z < 0.08 and compared their properties with elliptical galaxies located in a high-density environment such as the Coma supercluster. Aims. Our aim is to probe the role of environment on the morphological transformation...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2016 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/133763 |
| Acceso en línea: | http://hdl.handle.net/10261/133763 |
| Access Level: | acceso abierto |
| Palabra clave: | Galaxies: star formation Galaxies: fundamental parameters Galaxies: formation Galaxies: photometry Galaxies: elliptical and lenticular, cD Galaxies: structure |
| Sumario: | Context. We have studied a sample of 89 very isolated, elliptical galaxies at z < 0.08 and compared their properties with elliptical galaxies located in a high-density environment such as the Coma supercluster. Aims. Our aim is to probe the role of environment on the morphological transformation and quenching of elliptical galaxies as a function of mass. In addition, we elucidate the nature of a particular set of blue and star-forming isolated ellipticals identified here. Methods. We studied physical properties of ellipticals, such as color, specific star formation rate, galaxy size, and stellar age, as a function of stellar mass and environment based on SDSS data. We analyzed the blue and star-forming isolated ellipticals in more detail, through photometric characterization using GALFIT, and infer their star formation history using STARLIGHT. Results. Among the isolated ellipticals ≈ 20% are blue, ≤ 8% are star forming, and ≈ 10% are recently quenched, while among the Coma ellipticals ≈ 8% are blue and just ≤ 1% are star forming or recently quenched. There are four isolated galaxies (≈ 4.5%) that are blue and star forming at the same time. These galaxies, with masses between 7 × 10 and 2 × 10 h MO, are also the youngest galaxies with light-weighted stellar ages ≤ 1 Gyr and exhibit bluer colors toward the galaxy center. Around 30-60% of their present-day luminosity, but only <5% of their present-day mass, is due to star formation in the last 1 Gyr. Conclusions. The processes of morphological transformation and quenching seem to be in general independent of environment since most of elliptical galaxies are >red and dead>, although the transition to the red sequence should be faster for isolated ellipticals. In some cases, the isolated environment seems to propitiate the rejuvenation of ellipticals by recent (<1 Gyr) cold gas accretion. |
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