6,373 research outputs found
The Internal Dynamics of Globular Clusters
Galactic globular clusters are ancient building blocks of our Galaxy. They
represent a very interesting family of stellar systems in which some
fundamental dynamical processes have been taking place for more than 10 Gyr,
but on time scales shorter than the age of the universe. In contrast with
galaxies, these star clusters represent unique laboratories for learning about
two-body relaxation, mass segregation from equipartition of energy, stellar
collisions, stellar mergers, core collapse, and tidal disruption. This review
briefly summarizes some of the tremendous developments that have taken place
during the last two decades. It ends with some recent results on tidal tails
around galactic globular clusters and on a very massive globular cluster in
M31.Comment: An invited review (32 pages, 7 figures) in "The Chaotic Universe:
Theory, Observations, Computer Experiments", Proceedings of the ICRA
Rome-Pescara workshop, eds. V.G. Gurzadyan and R. Ruffini (Singapore: World
Sci.), in pres
A variation equation for the wave forcing of floating thin plates
A variational equation is derived for a floating thin plate subject to wave forcing. This variational
equation is derived from the thin plate equations of motion by including the forcing due to the
wave through the integral equation derived using the free surface Green’s function. This equation
combines the optimum method forsolving the motion of a thin plate (the variational equation)
with the optimum method for solving the wave forcing of a floating body (the Green’s function
method). Solutions of the variational equation are presented for some simple thin plate geometries
using polynomial basis functions. The variational equation is extended to the case of plates of
variable properties and to multiple plates and example solutions are presented
Partisipasi Perempuan Dalam Pengelolaan Lingkungan Hidup
Women have strong links with the environment. In his role as manager of the household, they are more interacting with the environment and natural resources. The era of globalization has indirectly resulted in increasing the development of environmental pollution and environmental damage. Women and children are part of the citizens who have a direct impact of pollution. Women's health impaired due to unhealthy living environment will result indirectly on the health of children as the future generation. Law No. 32 of 2009 on the Protection and Management of Living (UUPPLH) has given the changes that are democratic; give broad authority to local governments and community involvement in giving priority to control environmental damage. The role of women is implicitly described in article 70 of the role of the community. The role of women in environmental protection under the act protection and environmental management can be a social control and the role of women in environmental policy-making through the legislature
Palomar 13: a velocity dispersion inflated by binaries ?
Recently, combining radial velocities from Keck/HIRES echelle spectra with
published proper motion membership probabilities, Cote et al (2002) observed a
sample of 21 stars, probable members of Palomar 13, a globular cluster in the
Galactic halo. Their projected velocity dispersion sigma_p = 2.2 +/-0.4 km/s
gives a mass-to-light ratio M/L_V = 40 +24/-17, about one order of magnitude
larger than the usual estimate for globular clusters. We present here radial
velocities measured from three different CCD frames of commissioning
observations obtained with the new ESO/VLT instrument FLAMES (Fibre Large Array
Multi Element Spectrograph). From these data, now publicly available, we
measure the homogeneous radial velocities of eight probable members of this
globular cluster. A new projected velocity dispersion sigma_p = 0.6-0.9 +/-0.3
km/s implies Palomar 13 mass-to-light ratio M/L_V = 3-7, similar to the usual
value for globular clusters. We discuss briefly the two most obvious reasons
for the previous unusual mass-to-light ratio finding: binaries, now clearly
detected, and more homogeneous data from the multi-fibre FLAMES spectrograph.Comment: 9 pages, 2 Postscript figure
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