Stellar kinematics and populations out to 1.5 effective radius in the
  elliptical galaxy NGC4636
  We present high quality long slit spectra along the major and minor axes out
to 1.5 effective radius ($R_e$) of the massive galaxy NGC4636 taken by
Hobby-Eberly Telescope (HET). Using Fourier Correlation Quotient (FCQ) method,
we measured the stellar line-of-sight velocity distribution along the axes.
Furthermore, six Lick/IDS indices
($H\beta,Mgb,Fe_{5015},Fe_{5270},Fe_{5335},Fe_{5406}$) are derived from the
clean spectrum. By comparing the measured absorption line strengths with the
predictions of Simple Stellar Populations (SSP) models, we derived ages, total
metallicity and $\alpha$ abundance profiles of the galaxy. This galaxy presents
old and $[\alpha/Fe]$ over abundant stellar populations. Indeed, using the SSP
model, we obtained the broadband color profiles. The theoretical colors match
well with the measured colors and present red sharp peaks at the galaxy center.
The sharp peaks of the colors are mainly shaped by the high metallicity in the
galaxy center. Interestingly, the galaxy has steep negative metallicity
gradients, but trend flattens outwards. This result likly suggests that the
center and outer regions of the galaxy formed through different formation
process.
