Tully-Fisher关系与重子Tully-Fisher关系的研究进展

Advances in the Research of Tully-Fisher Relation and Baryonic Tully-Fisher Relation

Tully-Fisher关系和重子Tully-Fisher关系(简称TFR和BTFR)反映盘星系光度(重子物质质量)与气体旋转速度之间的关系。TFR和BTFR不仅是宇宙中重要测距工具,还是检验宇宙学模拟正确性的重要标尺。早期人们用各种波段的光度研究TFR,其中I与R波段弥散最小;后来的工作也采用星系恒星质量与旋转速度的关系。相比于TFR,BTFR具有弥散更小、适用范围更广的优点。星系旋转速度研究上,干涉阵望远镜相对于单天线的主要优势包括能得到更高的空间分辨率和速度场,再借助倾斜环模型能将中性氢运动特征参数化;而像FAST这样的大口径单天线望远镜,由于灵敏度高,在探测超弥散星系(UDG)等暗弱源候选体方面有优势。除综述研究进展以外,还初步研究了大质量星系BTFR受气体含量的影响。

This work reviews Tully-Fisher relation and baryonic Tully-Fisher relation(TFR and BTFR),which are important scaling relations connecting galaxy luminosity and baryonic mass with its rotation velocity.TFR and BTFR both serve as the standard rules in comic distance measurements and thus are crucial in determining cosmological parameters.The TFR make use of photometries in several bands.Despite the scaling relation existing in different wavelength,the slope and scatter varies.This can be explained by the different formation histories of different main tracers,e.g.the mass-to-light ratio is lower at shorter wavelength which is contributed mainly by young stars.Among all bands,the I and R bands present the smallest scatter.In order to further reduce the scatter of TFR,the luminosity is later replaced with stellar mass.Compared to TFR,BTFR includes gas components.It has many advantages.For example,the scatter,especially the intrinsic scatter,of BTFR is even smaller than that of the(stellar mass)TFR.Such tight relation also holds at low-masses.Besides,BTFR is more compatible,as it applies not only to disky galaxies,but also for irregular galaxies.To obtain the rotation velocity of the galaxy gas component,two kinds of telescope are used,telescope arrays and single-dish telescopes.The telescope array is superior to the single-dish in providing high spatial resolution image and velocity field data.With the help of modern theories,such as the tilted-ring model,one could obtain the rotation curve.On the other hand,large single-dish telescopes like FAST have high sensitivities given their large area,which is very useful in detecting weak sources like ultra diffuse galaxies(UDGs).In this paper,we present our preliminary results on the dependence of BTFR of massive galaxies on their gas fraction.We combine ALFALFA survey data with SDSS data,finding evidence of the gas fraction dependence.While BTFR is nearly independent on gas fraction for massive galaxies,at low masses,a weak yet positive dependence on gas fraction presents itself.Further studies using upcoming large arrays like SKA could be able to provide more reliable data for the kinematical studies.