642 research outputs found
The set of autotopisms of partial Latin squares
Symmetries of a partial Latin square are determined by its autotopism group.
Analogously to the case of Latin squares, given an isotopism , the
cardinality of the set of partial Latin squares which
are invariant under only depends on the conjugacy class of the latter,
or, equivalently, on its cycle structure. In the current paper, the cycle
structures of the set of autotopisms of partial Latin squares are characterized
and several related properties studied. It is also seen that the cycle
structure of determines the possible sizes of the elements of
and the number of those partial Latin squares of this
set with a given size. Finally, it is generalized the traditional notion of
partial Latin square completable to a Latin square.Comment: 20 pages, 4 table
A SAURON look at galaxy bulges
Kinematic and population studies show that bulges are generally rotationally
flattened systems similar to low-luminosity ellipticals. However, observations
with state-of-the-art integral field spectrographs, such as SAURON, indicate
that the situation is much more complex, and allow us to investigate phenomena
such as triaxiality, kinematic decoupling and population substructure, and to
study their connection to current formation and evolution scenarios for bulges
of early-type galaxies. We present the examples of two S0 bulges from galaxies
in our sample of nearby galaxies: one that shows all the properties expected
from classical bulges (NGC5866), and another case that presents kinematic
features appropriate for barred disk galaxies (NGC7332).Comment: 4 pages, 3 figures, accepted for publishing in AN (refereed conf.
proc. of the Euro3D Science workshop, IoA Cambridge, May 2003
Towards a new classification of early-type galaxies: an integral-field view
In this proceeding we make use of the two-dimensional stellar kinematics of a
representative sample of E and S0 galaxies obtained with the SAURON
integral-field spectrograph to reveal that early-type galaxies appear in two
broad flavours, depending on whether they exhibit clear large-scale rotation or
not. We measure the level of rotation via a new parameter LambdaR and use it as
a basis for a new kinematic classification that separates early-type galaxies
into slow and fast rotators. With the aid of broad-band imaging we will
reinforce this finding by comparing our kinematic results to the photometric
properties of these two classes.Comment: 4 pages, 2 figures, to appear in "Pathways Through an Eclectic
Universe", J. H. Knappen, T. J. Mahoney, and A. Vazedekis (Eds.), ASP Conf.
Ser., 200
- …