711 research outputs found
Fusion Procedure for Cyclotomic Hecke Algebras
A complete system of primitive pairwise orthogonal idempotents for cyclotomic
Hecke algebras is constructed by consecutive evaluations of a rational function
in several variables on quantum contents of multi-tableaux. This function is a
product of two terms, one of which depends only on the shape of the
multi-tableau and is proportional to the inverse of the corresponding Schur
element
On representations of complex reflection groups G(m,1,n)
An inductive approach to the representation theory of the chain of the
complex reflection groups G(m,1,n) is presented. We obtain the Jucys-Murphy
elements of G(m,1,n) from the Jucys--Murphy elements of the cyclotomic Hecke
algebra, and study their common spectrum using representations of a degenerate
cyclotomic affine Hecke algebra. Representations of G(m,1,n) are constructed
with the help of a new associative algebra whose underlying vector space is the
tensor product of the group ring of G(m,1,n) with a free associative algebra
generated by the standard m-tableaux.Comment: 18 page
On representations of cyclotomic Hecke algebras
An approach, based on Jucys--Murphy elements, to the representation theory of
cyclotomic Hecke algebras is developed. The maximality (in the cyclotomic Hecke
algebra) of the set of the Jucys--Murphy elements is established. A basis of
the cyclotomic Hecke algebra is suggested; this basis is used to establish the
flatness of the deformation without use of the representation theory
Spitzer Observations of Transient, Extended Dust in Two Elliptical Galaxies: New Evidence of Recent Feedback Energy Release in Galactic Cores
Spitzer observations of extended dust in two optically normal elliptical
galaxies provide a new confirmation of buoyant feedback outflow in the hot gas
atmospheres around these galaxies. AGN feedback energy is required to prevent
wholesale cooling and star formation in these group-centered galaxies. In NGC
5044 we observe interstellar (presumably PAH) emission at 8 microns out to
about 5 kpc. Both NGC 5044 and 4636 have extended 70 microns emission from cold
dust exceeding that expected from stellar mass loss. The sputtering lifetime of
this extended dust in the ~1keV interstellar gas, ~10^7 yrs, establishes the
time when the dust first entered the hot gas. Evidently the extended dust
originated in dusty disks or clouds, commonly observed in elliptical galaxy
cores, that were disrupted, heated and buoyantly transported outward. The
surviving central dust in NGC 5044 and 4636 has been disrupted into many small
filaments. It is remarkable that the asymmetrically extended 8 micron emission
in NGC 5044 is spatially coincident with Halpha+[NII] emission from warm gas. A
calculation shows that dust-assisted cooling in buoyant hot gas moving out from
the galactic core can cool within a few kpc in about ~10^7 yrs, explaining the
optical line emission observed. The X-ray images of both galaxies are
disturbed. All timescales for transient activity - restoration of equilibrium
and buoyant transport in the hot gas, dynamics of surviving dust fragments, and
dust sputtering - are consistent with a central release of feedback energy in
both galaxies about 10^7 yrs ago.Comment: 13 pages. Accepted by ApJ; minor typos correcte
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