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Active star formation in N11B Nebula in the Large Magellanic Cloud: a sequential star formation scenario confirmed

The second largest HII region in the Large Magellanic Cloud, N11B has been surveyed in the near IR.We present JHKs images of the N11B nebula.These images are combined with CO(1-0) emission line data and with archival NTT and HST/WFPC2 optical images to address the star formation activity of the region.IR photometry of all the IR sources detected is given.We confirm that a second generation of stars is currently forming in the N11B region. Our IR images show the presence of several bright IR sources which appear located towards the molecular cloud as seen from the CO emission in the area.Several of these sources show IR colours with YSO characteristics and they are prime candidates to be intermediate-mass Herbig Ae/Be stars.For the first time an extragalactic methanol maser is directly associated with IR sources embedded in a molecular core.Two IR sources are found at 2"(0.5 pc) of the methanol maser reported position.Additionally, we present the association of the N11A compact HII region to the molecular gas where we find that the young massive O stars have eroded a cavity in the parental molecular cloud, typical of a champagne flow. The N11 region turns out to be a very good laboratory for studying the interaction of winds, UV radiation and molecular gas.Several photodissociation regions are found.