M.Iye@FMOS SWS, Kyoto, 14/1/04

Spin Distribution of Galaxies in ClustersMasanori Iye(NAOJ)

• Structure formation in the Universe#CMB, SDSS, 2dF, CDM simulations=> density distribution#Yet no serious observational/theoretical works on the origin of vortici

ty of galaxies • Revive the “origin of spiral structure” issue=> FMOS gives a new insight on this problem:• Method: Offset spectroscopy to probe statistical analysis on internal

kinematics + orientation, axis ratio: *1st MOS on centers, *2nd 3rd MOS with major axis offset Start with nearby clusters => distant clusters *MOIRCS slit are suited for individual studies. FMOS needed for cluster studies.

M.Iye@FMOS SWS, Kyoto, 14/1/04

All spirals are trailing?S

Z +

_

_

+

Far Near Near Far

Conspiracy of S/Z, +/ － , Near/Far defines spin vector & trailing/leading completely.

(1) S/Z , or (2) Near/Far & +/ －

=> gives the sign of the line of sight component (spin parity) of galaxies.

M.Iye@FMOS SWS, Kyoto, 14/1/04

• Spin parity conservation. Spin sum tend to be zero rather than random binomial distributio

n for groups ? (Yamagata et al.1989)

M.Iye@FMOS SWS, Kyoto, 14/1/04

Spin distribution in clusters: Pancake, Tidal torque, Primordial whirl… *Surely, orbital mixing adds complication....