标题： 基于IllustrisTNG50模拟的快速射电暴宿主星系的色散度量和旋转度量 显示英文标题

标题： The dispersion measure and rotation measure from fast radio burst host galaxies based on the IllustrisTNG50 simulation

摘要： 快速射电暴（FRB）将成为重要的宇宙学工具，随着越来越多的调查开展，观测到的FRB数量正在迅速增加。 大量具有色散度量（DM）和旋转量度（RM）的FRB样本可以用来研究星系际磁场。 然而，观测到的FRB的DM和RM有多个贡献者，必须量化这些贡献才能获得星系际介质（IGM）的DM和RM。 本文估计了FRB宿主星系对DM和RM的一个贡献。 我们展示了它如何随红移、星系类型和星系的恒星质量、倾角以及FRB的投影偏移而变化。 利用IllustrisTNG50模拟，我们在红移0<=z<=2范围内选择了16500个星系，恒星质量范围为9<=log(M*/Msun)<=12。 在每个星系中，我们计算了1000条视线的DM和RM贡献，并构建了DM和RM的概率密度函数。 我们发现，在给定红移下所有星系的固有DM分布可以用对数正态函数拟合，固有RM分布以0 rad m$^{-2}$对称，并可以用洛伦兹函数和两个高斯函数的组合来拟合。 这些函数的参数因不同红移、恒星质量、倾角和FRB偏移的星系子集而异。 这些变化是由于随着红移、恒星形成率（SFR）和恒星质量的增加，$n_e$也在增加，我们发现在较低红移处比较高红移处有更有序的磁场，这由更多具有磁场反转和高红移处随机磁场占主导地位的星系所表明。 我们估算了FRB宿主星系的DM和RM贡献，未来可以用于从FRB的观测DM和RM中分离出IGM的贡献。 我们预测，为了以95%的置信水平限制一个$\sigma_{\rm RM,IGM}$为2 rad m$^{-2}$的值，我们需要在z=0.5时观测95000个FRB，但在z=2时只需观测9500个FRB。 显示英文摘要

摘要： Fast radio bursts (FRB) will become important cosmological tools, as the number of observed FRBs is increasing rapidly with more surveys being carried out. A large sample of FRBs with dispersion measures (DM) and rotation measures (RM) can be used to study the intergalactic magnetic field. However, the observed DM and RM of FRBs have multiple contributors which must be quantified to obtain the intergalactic medium's (IGM) DM and RM. In this paper, we estimate one such contribution to DM and RM: that of FRB host galaxies. We show how it changes with redshift, galaxy type, and the stellar mass of the galaxies, inclination, and FRB's projected offset. Using the IllustrisTNG50 simulations, we selected 16500 galaxies at redshifts of 0<=z<=2, with stellar masses in the range 9<=log(M*/Msun)<=12. In each galaxy, we calculate the DM and RM contributions of 1000 sightlines, and construct DM and RM probability density functions. We find that the rest frame DM distributions of all galaxies at a given redshift can be fitted by a lognormal function, and the rest frame RM distribution is symmetric around 0 rad m$^{-2}$, and can be fitted by the combination of a Lorentzian and two Gaussian functions. The parameters of these functions change for different subsets of galaxies with different redshift, stellar mass, inclination, and FRB offset. These changes are due to an increasing $n_e$ with redshift, SFR, and stellar mass, and we find a more ordered B field at lower z compared to higher z, suggested by more galaxies with B field reversals and B fields dominated by random B field at higher z. We estimate the FRB host DM and RM contributions, which can be used in the future to isolate the IGM's contribution from the observed DM and RM of FRBs. We predict that to constrain an $\sigma_{\rm RM,IGM}$ of 2 rad m$^{-2}$ to 95% confidence level we need to observe 95000 FRBs at z=0.5, but only 9500 FRBs at z=2.