4 research outputs found
Star Formation and Dynamics in the Galactic Centre
The centre of our Galaxy is one of the most studied and yet enigmatic places
in the Universe. At a distance of about 8 kpc from our Sun, the Galactic centre
(GC) is the ideal environment to study the extreme processes that take place in
the vicinity of a supermassive black hole (SMBH). Despite the hostile
environment, several tens of early-type stars populate the central parsec of
our Galaxy. A fraction of them lie in a thin ring with mild eccentricity and
inner radius ~0.04 pc, while the S-stars, i.e. the ~30 stars closest to the
SMBH (<0.04 pc), have randomly oriented and highly eccentric orbits. The
formation of such early-type stars has been a puzzle for a long time: molecular
clouds should be tidally disrupted by the SMBH before they can fragment into
stars. We review the main scenarios proposed to explain the formation and the
dynamical evolution of the early-type stars in the GC. In particular, we
discuss the most popular in situ scenarios (accretion disc fragmentation and
molecular cloud disruption) and migration scenarios (star cluster inspiral and
Hills mechanism). We focus on the most pressing challenges that must be faced
to shed light on the process of star formation in the vicinity of a SMBH.Comment: 68 pages, 35 figures; invited review chapter, to be published in
expanded form in Haardt, F., Gorini, V., Moschella, U. and Treves, A.,
'Astrophysical Black Holes'. Lecture Notes in Physics. Springer 201
Prevalence of Wolbachia in the European honeybee, Apis mellifera carnica
Intracellular endosymbiont, Wolbachia spp., have been previously reported in many different orders of insects, but not in the European honeybee sub species Apis mellifera carnica. We first report the presence of Wolbachia spp. in the honeybee sub spp. Apis mellifera carnica of the order Hymenoptera. Using standard polymerase chain reaction (PCR) targeting of the 16S ribosomal RNA gene, we screened for Wolbachia spp. in honeybee Queen and workers collected from different parts of Germany. Results of the study revealed 100 infection status of Wolbachia in Apis mellifera carnica collected from different parts of Germany, confirming that the Wolbachia spp. were invariably present in the honeybee Queen and the workers screened. © IDOSI Publications, 2011