Author/s: L. Monteagudo, C. Gallart, M. Monelli, E. J. Bernard, P. B. Stetson
Reference: 2017 MNRAS 473 L16 | Link
The Large Magellanic Cloud (LMC) is the prototype of a whole class of galaxies, the Barred Magellanic Spirals, characterized by the presence of a prominent stellar structure in the form of a ‘bar’ in their centre, a single spiral arm emanating from an end of the bar and, often, one large star forming region. The origin and nature of the bars of this type of galaxies are still unknown, and the proximity of the LMC is key to study their characteristics in great detail. In this paper, we present the star formation history (that is, the amount of stars formed as a function of time, since the formation of this galaxy some 13.5 billion years till the present time), in two areas in the LMC bar, and in a number of fields in the surrounding inner disk. For this calculation, we have used data obtained with the ESO VLT and the Hubble Space Telescope. The star formation histories show the same patterns in all fields, both inside the bar and in the disk. They show, therefore, that no specific event of star formation can be identified with the formation of the LMC bar, which instead likely formed from a redistribution of disk material. Subsequently, bar and disk would have shared the same star forming events. The fact that the two fields in the bar (one in its centre, and one in its Northern rim) also share the same characteristics in terms of stellar content allows us to constrain the formation models for this type of bars.