@Article{MiloneRickPast:2008:StPoAb,
               author = "Milone, Andr{\'e} de Castro and Rickes, M. G. and Pastoriza, M. 
                         G.",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)}",
                title = "The elliptical galaxies NGC 1052 and NGC 7796: stellar populations 
                         and abundance alpha/Fe ratio",
              journal = "Astronomy \& Astrophysics",
                 year = "2008",
               volume = "PAPER\˙N1052\˙N7796",
                 note = "{arXiv:astro-ph/0703425 or arXiv:astro-ph/0703425v1 for this 
                         version}",
             keywords = "Ellipitical galaxies, Stars, ASTROPHYSICS.",
             abstract = "Context: The spatial distribution of the stellar populations 
                         inside a spheroidal system and their kinematical properties supply 
                         important informations about the formation process. Aims: We have 
                         performed a detailed stellar population analysis using long slit 
                         spectroscopic observations up to almost one effective radius of 
                         two different early-type galaxies of low density regions of the 
                         local Universe: NGC 1052, a E4 Liner prototype of a loose group 
                         that has a stellar rotating disc, and NGC 7796, a E1 of the field 
                         which shows a kinematically distinct core. The mean 
                         luminosity-weighted stellar age, metallicity, and alpha/Fe ratio 
                         along both photometric axes of them have been obtained in order to 
                         reconstruct the star formation history in their kinematically 
                         distinct subsystems. Methods: We have measured Lick indices and 
                         computed their radial gradients. They were compared with the 
                         predicted ones of simple stellar population models. We have also 
                         applied a stellar population synthesis. Results: The star 
                         characteristics are associated with their kinematics: they are 
                         older and alpha-enhanced in the bulge of NGC 1052 and core of NGC 
                         7796, while they show a strong spread of alpha/Fe and age along 
                         the disc of NGC 1052 and an outwards radial decreasing of them 
                         outside the core of NGC 7796. The age variation is possibly 
                         connected to the alpha/Fe one. Conclusions: Both galaxies were 
                         formed by processes in which the star formation occurred firstly 
                         at the bulge (NGC 1052) and nucleus (NGC 7796) 12-15 Gyr ago on 
                         short timescales (0.1-1 Gyr) providing an efficient chemical 
                         enrichment by SN-II. In the disc of NGC 1052, there is some spread 
                         of age and formation timescales around its stars. In NGC 7796, the 
                         star formation timescale had some outwards radial increasing along 
                         both axes.",
                  doi = "10.1051/0004-6361:20054615",
                  url = "http://dx.doi.org/10.1051/0004-6361:20054615",
                 issn = "0004-6361 and 1432-0746",
             language = "en",
           targetfile = "0703425v1.pdf",
        urlaccessdate = "02 maio 2024"
}