16,498 research outputs found
Galaxy population properties in the rich clusters MS0839.8+2938, 1224.7+2007 and 1231.3+1542
This paper discusses the galaxy populations of three rich clusters, with
redshift 0.19 (0839+29), 0.24 (1231+15), and 0.32 (1224+20), from the database
of the CNOC1 consortium. The data consist of spectra of 52 cluster members for
0839+29, 30 members for 1224+15, and 82 members for 1231+15, and there are
comparable numbers of field galaxy spectra. 0839+29 is compact with no strong
radial gradients, and possibly dusty. 1224+20 is isolated in redshift, has low
velocity dispersion around the cD galaxy, and low 4000A break. 1231+15 is
asymmetrical and we discuss the possibility that it may be a recent merger of
two old clusters. We find few galaxies in 0839+29 and 1231+15 with ongoing or
recently truncated star-formation.Comment: 16 pages and 20 diagrams, to appear in A
Virtual moduli cycles and Gromov-Witten invariants of noncompact symplectic manifolds
This paper constructs and studies the Gromov-Witten invariants and their
properties for noncompact geometrically bounded symplectic manifolds. Two
localization formulas for GW-invariants are also proposed and proved. As
applications we get solutions of the generalized string equation and dilation
equation and their variants. The more solutions of WDVV equation and quantum
products on cohomology groups are also obtained for the symplectic manifolds
with finitely dimensional cohomology groups. To realize these purposes we
further develop the language introduced by Liu-Tian to describe the virtual
moduli cycle (defined by Liu-Tian, Fukaya-Ono, Li-Tian, Ruan and Siebert).Comment: Final versio
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