  Elliptic flow has been measured by the BRAHMS experiment as a function of
transverse momentum and pseudorapidity for the Au+Au reaction at sqrt[s_{NN}] =
200 GeV. Identified-particle v2 (eta, pt) values were obtained with the two
BRAHMS spectrometers at pseudorapidities eta approximately equal to 0, 1, and
3.4. The results show that the differential v2(eta, pt) values for a given
particle type are essentially constant over the covered pseudorapidity range.
It is suggested that the dominant cause of the observed fall-off of the
integral v2 values going away from mid-rapidity is a corresponding softening of
the particle spectra .
