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Star formation in the Magellanic Clouds

by Michele Cignoni (STScI, USA)

Jan 09, 2014 from 02:00 PM to 04:00 PM

Where Seminars' room, floor -1, via Ranzani 1

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Using space based (HST) and ground based (VLT Survey Telescope - VST)
observations, we have undertaken a systematic study of the star
formation histories (SFHs) of the Magellanic Clouds, as determined by
analysis of resolved stellar populations. I'm presenting here some of the
main results and new observations.

Concerning the SMC, I will describe the stellar content of six
deep HST/ACS fields located in the SMC Bar, in the Wing in the
direction of the LMC, and in the outskirts. The recovered SFHs
suggests a common low star formation pace until 5-7 Gyr ago, followed by a
two-three times higher activity from then on. This is remarkable since at
that epoch, dynamical models predict a negligible influence of either the
Large Magellanic Cloud or the Milky Way. The
age-metallicity relations we infer from our best fitting models are
monotonically increasing with time, or constant, with no evidence of dips.
To complete this work, we have an ongoing Guaranteed Time
Observation program at the VST (PI Ripepi) designed to cover with deep
photometry the whole SMC and the Bridge connecting it to the
LMC. These CMDs are disclosing for the first time the SFH of the whole SMC
over the entire Hubble time, covering a much larger area with
considerably better image quality than in previous systematic studies.

Concerning the LMC, I will present preliminary results from the Hubble
Tarantula Treasury Project (HTTP), a multi-wavelength HST/ACS/WFC3 imaging
survey for the entire Tarantula Nebula, aka 30 Doradus, the most active
star forming region in the Local Group. This dataset
offers unprecedented opportunities to probe the formation of massive stars
(~ 300 O-stars) and young stellar clusters as well as their
evolution. The resulting maps of the stellar content will provide the
basis for investigations of star formation in an environment
resembling the extreme conditions found in starburst galaxies and in the
early universe.