Evolutionary properties of the low-luminosity galaxy population in the NGC5044 Group
In this third paper of a series we present Johnson-Gunn B, g, V, r, i, z multicolour photometry for 79 objects, including a significant fraction of the faintest galaxies around NGC5044, assessing group membership on the basis of apparent morphology (through accurate Sérsic-profile fitting) and low-r...
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| Autores principales: | , , , |
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| Formato: | Articulo |
| Lenguaje: | Inglés |
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2012
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| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/84262 |
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I19-R120-10915-84262 |
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dspace |
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Universidad Nacional de La Plata |
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I-19 |
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R-120 |
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SEDICI (UNLP) |
| language |
Inglés |
| topic |
Ciencias Astronómicas Galaxies: clusters: individual: NGC5044 Group Galaxies: dwarf Galaxies: elliptical and lenticular, cD Galaxies: fundamental parameters Galaxies: photometry |
| spellingShingle |
Ciencias Astronómicas Galaxies: clusters: individual: NGC5044 Group Galaxies: dwarf Galaxies: elliptical and lenticular, cD Galaxies: fundamental parameters Galaxies: photometry Buzzoni, A. Cellone, Sergio Aldo Saracco, P. Zucca, E. Evolutionary properties of the low-luminosity galaxy population in the NGC5044 Group |
| topic_facet |
Ciencias Astronómicas Galaxies: clusters: individual: NGC5044 Group Galaxies: dwarf Galaxies: elliptical and lenticular, cD Galaxies: fundamental parameters Galaxies: photometry |
| description |
In this third paper of a series we present Johnson-Gunn B, g, V, r, i, z multicolour photometry for 79 objects, including a significant fraction of the faintest galaxies around NGC5044, assessing group membership on the basis of apparent morphology (through accurate Sérsic-profile fitting) and low-resolution (R= 500-1000) optical spectroscopy to estimate the redshift for 21 objects. Early- and late-type systems are found to be clearly separate in Sérsic parameter space, with the well-known luminosity versus shape relation being mostly traced by different morphological types spanning different ranges in the shape parameter n. A significantly blue colour is confirmed for Magellanic irregulars (Sm/Ims), while a drift toward bluer integrated colours is also an issue for dwarf ellipticals (dEs). Both features point to moderate but pervasive star-formation activity even among nominally 'quiescent' stellar systems. Together, dEs and Ims provide the bulk of the galaxy luminosity function, around M(g) ≃-18.0 ± 1.5, while the S0 and dwarf spheroidal (dSph) components dominate the bright and faint-end tails of the distribution respectively. This special mix places the NGC5044 Group just 'midway' between the high-density cosmic aggregation scale typical of galaxy clusters and the low-density environment of looser galaxy clumps like our Local Group. The bright mass of the 136 member galaxies with available photometry and morphological classification, as inferred from appropriate M/L model fitting, amounts to a total of 2.3 × 10 12M ⊙. This is one seventh of the total dynamical mass of the group, according to its X-ray emission. The current star-formation rate within the group turns to be about 23M ⊙yr -1, a figure that may however be slightly increased as a result of the evident activity among dwarf ellipticals, as shown by enhanced Hβ emission in their spectra. Lick narrow-band indices have been computed for 17 galaxies, probing all the relevant atomic and molecular features in the 4300-5800Å wavelength range. Dwarf ellipticals are found to share a subsolar metallicity (-1.0 ≲ [Fe/H] ≲- 0.5), with a clear decoupling between iron and α elements, as already established for high-mass systems. Both dEs and dS0s are consistent with a high age, about one Hubble time, although a possible bias towards higher values of age may be induced by the gas emission affecting the Hβ strength. © 2012 The Authors Monthly Notices of the Royal Astronomical Society |
| format |
Articulo Articulo |
| author |
Buzzoni, A. Cellone, Sergio Aldo Saracco, P. Zucca, E. |
| author_facet |
Buzzoni, A. Cellone, Sergio Aldo Saracco, P. Zucca, E. |
| author_sort |
Buzzoni, A. |
| title |
Evolutionary properties of the low-luminosity galaxy population in the NGC5044 Group |
| title_short |
Evolutionary properties of the low-luminosity galaxy population in the NGC5044 Group |
| title_full |
Evolutionary properties of the low-luminosity galaxy population in the NGC5044 Group |
| title_fullStr |
Evolutionary properties of the low-luminosity galaxy population in the NGC5044 Group |
| title_full_unstemmed |
Evolutionary properties of the low-luminosity galaxy population in the NGC5044 Group |
| title_sort |
evolutionary properties of the low-luminosity galaxy population in the ngc5044 group |
| publishDate |
2012 |
| url |
http://sedici.unlp.edu.ar/handle/10915/84262 |
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AT buzzonia evolutionarypropertiesofthelowluminositygalaxypopulationinthengc5044group AT cellonesergioaldo evolutionarypropertiesofthelowluminositygalaxypopulationinthengc5044group AT saraccop evolutionarypropertiesofthelowluminositygalaxypopulationinthengc5044group AT zuccae evolutionarypropertiesofthelowluminositygalaxypopulationinthengc5044group |
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Repositorios |
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