Devendra Ojha
Tata Institute of Fundamental Research (TIFR), Mumbai (Bombay)

Abstract
So far young brown dwarfs (YBDs) search has been limited to the nearby star forming regions (< 500 pc). With the high sensitivity and high resolution NIR observations, it is now possible to detect and characterize the YBDs in distant massive star forming regions, which are more typical in the galactic scale. W3 Main and NGC 7538 are well-known distant massive star forming regions and contain the rich clusters of young stars which have recently been formed. Several different evolutionary stages have been discovered in these complexes with considerable substructures and it is expected that the stellar population in these star forming regions is primarily composed of low mass pre-main-sequence stars. In this talk, I will describe results from our ongoing investigation of low-mass stellar and substellar populations in W3 Main and NGC 7538, using the deep NIR observations (K ~ 20 mag at 10-sigma) with the Subaru Telescope. There appears to be a substantial substellar population and we expect to reveal the IMFs down to 30 Jupiter mass regime in the W3 Main and NGC 7538 regions, by detecting YBDs based on the NIR colors and luminosities. It is unlikely that the mass functions show the presence of cutoff and turnover at least at the hydrogen-burning limit and likely at the deuterium-burning limit. Our results therefore provide the key clues to a census of very low mass stars and the IMF down to a few Jupiter-mass regime for the first time in distance massive star forming regions.

2010 June 01, 13:30

IA/U.Porto
Centro de Astrofísica da Universidade do Porto (Auditorium)
Rua das Estrelas, 4150-762 Porto