Detalles de publicación
PP 018018
The star formation history of the Sextans dwarf spheroidal galaxy: a true fossil of the pre-reionization era
(1)(Instituto de Astrofísica de Canarias, Vía Láctea S/N, E-38200 La Laguna, Tenerife, Spain; Department of Astrophysics, University of La Laguna, E-38200 La Laguna, Tenerife, Canary Islands, Spain; Dipartimento di Fisica e Astronomia "Galileo Galilei", Universitá degli Studi di Padova, Vicolo dell'Osservatorio 3, I-35122 Padova, Italy), (2)(Instituto de Astrofísica de Canarias, Vía Láctea S/N, E-38200 La Laguna, Tenerife, Spain; Department of Astrophysics, University of La Laguna, E-38200 La Laguna, Tenerife, Canary Islands, Spain), (3)(INAF-Osservatorio Astronomico d'Abruzzo, Via M. Maggini, sn. 64100 Teramo, Italy; Instituto de Astrofísica de Canarias, Vía Láctea S/N, E-38200 La Laguna, Tenerife, Spain), (4)(Department of Astrophysics, University of La Laguna, E-38200 La Laguna, Tenerife, Canary Islands, Spain; Instituto de Astrofísica de Canarias, Vía Láctea S/N, E-38200 La Laguna, Tenerife, Spain), (5)(Dipartimento di Fisica e Astronomia "Galileo Galilei", Universitá degli Studi di Padova, Vicolo dell'Osservatorio 3, I-35122 Padova, Italy; INAF-Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, I-35122 Padova, Italy)
We present the star formation history (SFH) of the Sextans dwarf spheroidal galaxy based on deep archive B, I photometry taken with Suprime-Cam at Subaru telescope focusing our analysis on the inner region of the galaxy, fully located within the core radius. Within the errors of our SFH we have not detected any metallicity gradient along the considered radial distance interval. As a main result of this work we can state that the Sextans dwarf spheroidal stopped forming stars less than ˜1.3 Gyr after Big Bang in correspondance to the end of the reionization epoch. We have been able to constrain the duration of the main burst of star formation to ˜0.6 Gyr. From the calculation of the mechanical luminosity released from supernovae (SNe) during the brief episode of star formation, there are strong indications that SNe could have played an important role in the fate of Sextans, by removing almost completely the gas component, so preventing a prolonged star formation.