Star Formation Regions
Particle Acceleration by Young Stars
Although the usual assumption is that supernova explosions are the
dominant source of cosmic rays, it has been speculated that cosmic rays
are also accelerated in stellar winds around massive young stars before
they explode as supernovae, or around star clusters. Indeed, there is
growing evidence from gamma-ray data for a population of sources related
to young stellar clusters and environments with strong stellar winds.
However, lack of detection sensitivity currently prevents the detailed
study and clear identification of these sources of gamma radiation.
CTA aims at a better understanding of the relationship between star
formation processes and gamma-ray emission. CTA can establish
experimentally whether there is a direct correlation between star
formation rate and gamma-ray luminosity when convection and absorption
processes in the different environments are taken into account.
|Dymanic duo - the two starburst galaxies NGC 253
(left) and M82 (right) produce VHE gamma rays. Image credits: NGC 253-
ESO; M82 - NASA/STScI
Starburst galaxies are undergoing rates of star formation much higher than in our own galaxy. Both the VERITAS and H.E.S.S.
arrays have performed deep observations of the nearest starburst
galaxies, and found them, at the limit of their sensitivity, emitting
TeV gamma-rays. Future CTA observations, with improved sensitivity at
higher and lower energies, will reveal details of this radiation which
in turn will help to understand the spectra, provide constraints on the
physical emission scenarios, and extend the study of the relationship
between star formation processes and gamma-ray emission to extragalactic
Ohm et al., H.E.S.S. Observations of Massive Stellar Clusters; http://arxiv.org/abs/0906.2637
Romero et al., Gamma Rays from Massive Protostars; http://arxiv.org/abs/0908.0931