The hypervelocity OB stars in the Milky-Way Galaxy were ejected from the central regions some 10-100 million years ago. The authors argue that these stars, as well as many more abundant bound OB ...stars in the innermost few parsecs, were generated by the interactions of an AGN jet from the central black hole with a dense molecular cloud. Considerations of the associated energy and momentum injection have broader implications for the possible origin of the Fermi bubbles and for the enrichment of the intergalactic medium.
To answer questions on the start and duration of the epoch of reionisation, periods of galaxy mergers and properties of other cosmological encounters, the cosmic star formation history, rho or CSFH, ...is of fundamental importance. Using the association of long-duration gamma-ray bursts (LGRB) with the death of massive stars and their ultra-luminous nature, the CSFH can be probed to higher redshifts than current conventional methods. Observations by the gamma-ray burst near-infrared detector over the past 4 years have, for the first time, acquired highly complete LGRB samples. The CSFH is modelled using empirical fits to the galaxy mass function and galaxy star formation rates. It is found that there is no strong preference for a metallicity cut or fixed galaxy mass boundaries and that there are no unknown redshift effects, in contrast to previous work which suggest values of ... . From the best-fit models obtained, the authors predict that similar to 1.2% of the LGRB burst sample exists above z = 6. (ProQuest: ... denotes formulae/symbols omitted.)
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