标题： Tully-Fisher关系的低光度端 显示英文标题

标题： The faint end of the Tully-Fisher relation

摘要： 我们研究了矮星系两个样本中HI线宽与光学光度之间的关系，特别关注倾斜校正的准确性。 第一个样本由旋转支持的星系组成，以DDO 154为原型。 它们的HI线宽显著大于根据Tully-Fisher关系外推所预测的值。 从外推的Tully-Fisher关系的偏离与与距离无关的质量-光度比M_HI/L_B相关。 对于这些气体丰富的星系，重子校正太小，无法解释与Tully-Fisher关系的偏离，除非假设恒星种群的质光比(M/L_B)_* ≤ 0.25。 第二个样本包含旋转速度和随机速度相当的矮星系。 这个样本以Leo A为原型，与经典Tully-Fisher关系向低光度外推是一致的。 这些矮星系并不特别富含气体，但它们在其HI半径内质量主要由重子物质主导。 我们认为，任何偏离星系向Tully-Fisher关系的演化将结合通过径向传输HI来减小线宽，以及由于积累更大的恒星质量而导致光度增加。 显示英文摘要

摘要： We have studied the relation between HI linewidth and optical luminosity in two samples of dwarf galaxies, with special attention to the accuracy of the inclination correction. The first sample consists of rotationally supported galaxies, and has DDO 154 as a prototype. They have HI linewidths significantly larger than predicted by an extrapolation of the Tully-Fisher relation. The deviation from the extrapolated Tully-Fisher relation correlates with the distance-independent mass-to-luminosity ratio M_HI/L_B. The baryonic correction for these gas rich galaxies is too small to explain the deviation from the Tully-Fisher relation, unless a small mass-to-light ratio (M/L_B)_* <= 0.25 for the stellar population is assumed. The second sample contains dwarf galaxies with comparable rotational and random velocities. This sample, having Leo A as a prototype, is consistent with an extrapolation of the classical Tully-Fisher relation to lower luminosities. These dwarf galaxies are not particularly rich in gas, but their mass is dominated by baryonic matter within their HI radius. We suggest that any evolution of the deviating galaxies towards the Tully-Fisher relation will combine a decrease in linewidth by radial transport of HI with an increase in luminosity due to a larger accumulated stellar mass.