Instrument Scientist for OMEGACAM at VST. Instrument Scientist for VIMOS at UT3@VLT. Prior Instrument Scientist for HAWK-I at UT4@VLT.
After showing that the field of the LMC has an IMF with an upper mass slope consistent with the Salpeter one, we approached the other emblematic cluster for which a deviant value has been claimed. We have shown that the IMF slope in the upper mass range is also consitent with the Salpeter value. The details can be found in Espinoza, Selman and Melnick (2009), soon to appear in A\&A. You can see an ESO press release.
After having determined that the stellar population in the field and in the ionizing cluster of 30 Doradus both have a Salpeter slope IMF we have discussed the implications in the context of Kroupa and Weidner's arguments against the field IMF being the same as that of the IMF of stars in clusters. We presented our arguments in Protostars and Planets VI (Hawaii, 2005). We have refined the study since then, recognizing the significance of the statistics of the maximal star mass-cluster mass presented by Weidner and Kroupa by reproducing their results with our own simulations. The figure shows the contour map of this statistics showing the area permitted by the purely random sampling model but not covered by observations. We are using n-body simulations to determine the gravitational stability of the different parts of this diagram.
With Hernan Quintana from PUC and J. Melnick at ESO I have developed a technique to analyze imaging data in the optical in a manner analogous to that used in the infrared permitting accurate sky subtraction. The technical details are found in Melnick, Selman, and Quintana (1999). We are currently applying this technique to study the distribution of light in two clusters of galaxies. Preliminary results are presented in A&A 463, 833 (2007)
With Jorge Melnick we have recently found that between 7 and 40 solar the stellar IMF in the field of the 30 Doradus superassociation has a Salpeter slope. Dor details see this paper.
With Jorge Melnick, Roberto Terlevich and Guillermo Bosch we have written a series of papers on the properties of the ionizing cluster of 30 Doradus. Paper I deals with the data analysis and the distribution of reddening; Paper II, written by Bosch et al. deals with the spectroscopic study of the massive stellar population; Paper III, by Selman et al. deals with the IMF and star formation history; and Paper IV, by Bosch et al. started as an attempt to study the dynamics of the cluster and ended being a study of the binary fraction.