标题： NGC 5728中的反向旋转中心组分 显示英文标题

标题： A counterrotating central component in NGC 5728

摘要： 我们基于I波段光度测量和近红外Ca II三重线区域的长缝光谱观测，对棒旋星系NGC 5728中的恒星运动学进行了详细研究。对恒星视线速度分布（LOSVD）的分析显示，在棒的中心区域存在一个冷的（v/sigma~2.5）顺行的$S$形状的速度组分，该组分与一个较暗且更热的（v/sigma~0.5）逆转速度组分共存于中心4 kpc范围内。在距离核中心4 kpc以外的区域，LOSVD显示出恒星棒的运动学特征。将速度组分的径向表面亮度轮廓与从I波段图像获得的轮廓进行比较显示，逆转核心遵循r^(1/4)轮廓，而S形组分则不遵循平坦棒的表面亮度轮廓。讨论了在NGC 5728棒中心发现的这种运动学特征的几种可能情景。 显示英文摘要

摘要： We present a detailed study of the stellar kinematics in the barred galaxy NGC 5728 based on I-band photometry and long-slit spectroscopic observations in the region of the near-IR Ca II triplet. The analysis of the stellar line-of-sight velocity distribution (LOSVD) has revealed, in the central regions of the bar, the presence of a cold (v/sigma~2.5) prograde $S$-shaped velocity component that coexists in the central 4 kpc with a fainter and hotter (v/sigma~0.5) counterrotating component. Beyond 4 kpc from the nucleus the LOSVD shows the stellar bar kinematics. The comparison of the radial surface brightness profile of the velocity components with that obtained from an I-band image shows that the counterrotating core follows a r^(1/4) profile, while the S-shaped component does not follows the flat bar surface brightness profile. Several possible scenarios accounting for such kinematic signatures found in the center of the bar in NGC 5728 are discussed.