SF-WF-MSF · Wide Field Studies of Star Forming Regions

Wide field studies of star forming regions

The research and training objectives of this funded project were to: a) exploit the wide-field infrared surveys (UKIDSS, VISTA, UWISH2) to address problems in star formation, with focus on molecular clouds, massive stars and triggered star formation; b) to train early-stage researchers in the multi-wavelength analysis, with focus on wide-field infrared data; c) to exploit the human resources from the partner country (India) to accomplish the goals and also to use the important Indian radio astronomical facility, namely 'Giant metre wave radio telescope'. The project has had very good success in meeting these objectives, as elaborated in the details below: 1. Research highlights (ordered according to its scientific impact / importance): a) Discovery of radiatively driven Rayleigh-Taylor instabilities in the outflow cavity of a massive protostar: The formation of massive stars is an enigmatic topic in astrophysics revolving around a singular problem: dissipation of the intense radiation pressure in the early stages of massive star formation that is capable of reversing accretion flows. Theoretical solutions to this problem had long predicted that radiative driven Rayleigh-Taylor instabilities in the outflow cavities will fall back on to the disk plane allowing radiation to dissipate, while re-fuelling the material to accretion disk, fostering growth of massive stars. The Rayleigh-Taylor instabilities are expected to be short-lived representing a fraction of the time in the rapid formation phases of a massive star, and are therefore very challenging to observationally catch in act. The Indian team, with their expertise in far-infrared balloon-borne astronomy have for a long time studied one of the most luminous and powerful source in the sky, available in the southern hemisphere. While revisiting this special target using advanced data from European Union (EU) facilities (primarily VLT) through this collaboration, we discovered the Rayleigh-Taylor instabilities in this target, as the target itself is very rare and possess special characteristics that were congenial for the discovery. This discovery is a major advancement of the field of massive star formation. b) Triggered star formation: Fresh star formation process is known to be triggered by the influence of stellar winds and ultra-compact HII regions driven by massive stars. But the triggered star formation is mostly studied qualitatively in astronomy and quantitative and / or direct evidences are very few. Through a detailed multi-wavelength, wide-field studies of a few nearby sites of triggered star formation, the research undertaken in the auspices of this project has arrived at some quantitative results, elaborating on the influence of individual mechanisms that is responsible for the triggering of fresh star formation. c) The sequence of low and high mass star formation in embedded stellar clusters: An important question is star formation is 'What kind of stars are made first'? 'The low mass ones or the high mass ones'? Again by exploiting the deep data from wide-field surveys, one of the investigations from this project demonstrates that it is the low mass stars that form prior to massive stars in a common environment of stellar embryos known as embedded clusters. 2. Academic training and exchange: Through this project, several researchers, primarily early-stage researchers in India were trained in various aspects of the analysis of the wide-field infrared data. They were also exposed and trained to utilise various public surveys executed by EU consortia using the EU funded telescopes and wide-field camera's. The training was accomplished by directly using the available data from many of the surveys to accomplish the science goals that were set out in the funded IRSES project. The primary impact of this training is an increased utility of the EU funded public survey data by larger community of researchers (in this particular case, the Indian community), thus increasing the science returns of the public data and hence the money value of EU funded survey projects. Two early-stage researchers trained through this IRSES project have now acquired experienced researcher positions in France and Portugal. The project is therefore successful in bringing human-resources to EU countries with advanced training. European researchers trained through this project are now exposed to the powerful Indian radio astronomical facility, namely the 'Giant metre wave radio telescope' operated by NCRA / TIFR. Data from this telescope is used in many of the publications from this IRSES project. The trained EU researchers are now in a position to further access this facility and utilise it for research goals providing a mutual contribution from the Indian community. They were also trained in radiative transfer modelling of massive star forming regions that was traditionally carried out by the TIFR group, experienced in far-infrared astronomy. 3. Socio-economic impact: Traditionally, researchers from India have migrated to the west. Through this project, EU researchers have had the chance to visit, see and understand the evolving situation, in particular, the competitive facilities and working environments offered in India. Additionally, they were exposed to the rich cultural aspects in India that are usually not taught or commonly known through basic education in EU countries. These exchanges will have a positive socio-economic impact over the long run, in a world that is constantly heading towards globalisation surpassing the barriers of cultures, ethnicities and religion.

Data: CORDIS, © European Union