Title: Kinematics of galaxies in Compact Groups. Studying the B-band Tully-Fisher relation Show Chinese title

Title: 致密星系群中星系的运动学。 研究B波段Tully-Fisher关系

Abstract: We obtained new Fabry-Perot data cubes and derived velocity fields, monochromatic and velocity dispersion maps for 28 galaxies in the Hickson compact groups 37, 40, 47, 49, 54, 56, 68, 79 and 93. We find that one third of the non-barred compact group galaxies have position angle misalignments between the stellar and gaseous components. This and the asymmetric rotation curves are clear signatures of kinematic perturbations, probably due to interactions among compact group galaxies. A comparison between the B-band Tully-Fisher relation for compact group galaxies and that for the GHASP field-galaxy sample shows that, despite the high fraction of compact group galaxies with asymmetric rotation curves, these lie on the Tully-Fisher relation defined by galaxies in less dense environments, although with more scatter. This is in agreement with previous results, but now confirmed for a larger sample of 41 galaxies. We confirm the tendency for compact group galaxies at the low-mass end of the Tully-Fisher relation (HCG 49b, 89d, 96c, 96d and 100c) to have either a magnitude that is too bright for its mass (suggesting brightening by star formation) and/or a low maximum rotational velocity for its luminosity (suggesting tidal stripping). These galaxies are outside the Tully Fisher relation, at the 1 sigma level, even when the minimum acceptable values of inclinations are used to compute their maximum velocities. The inclusion of such galaxies with v<100 km/s in the determination of the zero point and slope of the compact group B-band Tully-Fisher relation would strongly change the fit, making it different from the relation for field galaxies, a fact that has to be kept in mind when studying scaling relations of interacting galaxies, specially at high redshifts. Show Chinese abstract

Abstract: 我们获得了哈克森致密星系群37、40、47、49、54、56、68、79和93中28个星系的新Fabry-Perot数据立方体，并推导出速度场、单色图像以及速度弥散图。我们发现三分之一的非棒旋致密星系组星系在恒星和气体组分之间存在位置角错配。这一现象与不对称旋转曲线一起，明确表明了动力学扰动的迹象，可能由于致密星系组内星系之间的相互作用。将致密星系组星系的B波段Tully-Fisher关系与GHASP场星样本的Tully-Fisher关系进行比较后发现，尽管致密星系组星系中有较高比例的不对称旋转曲线，但它们仍位于由密度较低环境中星系定义的Tully-Fisher关系上，不过离散度更大。这与先前的结果一致，但现在通过对更大样本（41个星系）的确认得到了进一步验证。我们证实了Tully-Fisher关系低质量端的致密星系组星系（HCG 49b、89d、96c、96d和100c）要么具有相对于其质量过亮的亮度（暗示由恒星形成引起的增亮），要么具有相对于其光度较低的最大旋转速度（暗示潮汐剥离）。即使使用最小可接受的倾角值来计算这些星系的最大速度，它们仍然偏离Tully-Fisher关系约1σ水平。将这些最大速度v<100 km/s的星系纳入致密星系组B波段Tully-Fisher关系零点和斜率的确定过程中，会显著改变拟合结果，使其不同于场星的关系，这一点在研究相互作用星系的尺度关系时，特别是在高红移情况下，必须牢记在心。