The integrated stellar content of dark matter halos
Alexie Leauthaud, Matthew R. George, Peter S. Behroozi, Kevin Bundy, Jeremy Tinker, Risa H. Wechsler, Charlie Conroy, Alexis Finoguenov, Masayuki Tanaka
备注:
Submitted to ApJ. 16 Pages, 11 Figures. Comments Welcome
对星系中恒星总量的测量,作为宿主晕质量的函数,包含了关于调节恒星形成过程效率的关键线索。我们用两种互补的方法导出了恒星总质量分数f_star随晕质量M_(500)c(z=0.2 ~ z=1)的变化关系。首先,我们推导出f_star使用统计Halo职业分布模型联合约束的数据从透镜,集群,和恒星质量函数。这种方法使我们能够探测f_star在更广泛的晕质量范围比集团或集群目录。其次,我们使用COSMOS X射线星表在群尺度上推导出f_star,并证明了两种方法的一致性在30%以内。我们用丰度匹配方法量化了f_star上的系统不确定性,我们表明,f_star上的统计不确定性(~10%)与恒星质量测量相关的系统不确定性(~45%,不包括IMF不确定性)相比相形见绌。假设一个夏布里耶IMF,我们发现在M500 c =10^13 Msun时0.012<f_star<0.025,在M500 c =10^14 Msun时0.0057<f_star<0.015。这些数值大大低于先前公布的估计数。我们调查这种差异的原因,并发现以前的工作高估了f_star由于不准确的恒星质量估计和/或因为他们假设所有星系的组中的早期类型的星系具有恒定的质光比的组合。与先前的说法相反,我们的结果表明,对于10^13 Msun以上的晕,f_star的平均值总是显著低于f_gas。结合我们的结果与最近发表的气体质量分数,我们发现在R500 c的f_star+f_gas相比,宇宙平均值的不足。这种不足随着晕质量的变化而变化,越低的晕质量越大。
英文摘要:
Measurements of the total amount of stars locked up in galaxies as a function of host halo mass contain key clues about the efficiency of processes that regulate star formation. We derive the total stellar mass fraction f_star as a function of halo mass M500c from z=0.2 to z=1 using two complementary methods. First, we derive f_star using a statistical Halo Occupation Distribution model jointly constrained by data from lensing, clustering, and the stellar mass function. This method enables us to probe f_star over a much wider halo mass range than with group or cluster catalogs. Second, we derive f_star at group scales using a COSMOS X-ray group catalog and we show that the two methods agree to within 30%. We quantify the systematic uncertainty on f_star using abundance matching methods and we show that the statistical uncertainty on f_star (~10%) is dwarfed by systematic uncertainties associated with stellar mass measurements (~45% excluding IMF uncertainties). Assuming a Chabrier IMF, we find 0.012<f_star<0.025 at M500c=10^13 Msun and 0.0057<f_star<0.015 at M500c=10^14 Msun. These values are significantly lower than previously published estimates. We investigate the cause of this difference and find that previous work has overestimated f_star due to a combination of inaccurate stellar mass estimators and/or because they have assumed that all galaxies in groups are early type galaxies with a constant mass-to-light ratio. Contrary to previous claims, our results suggest that the mean value of f_star is always significantly lower than f_gas for halos above 10^13 Msun. Combining our results with recently published gas mas fractions, we find a shortfall in f_star+f_gas at R500c compared to the cosmic mean. This shortfall varies with halo mass and becomes larger towards lower halos masses.
We investigate how much can be learnt about four types of primordial non-Gaussianity (PNG) from small-scale measurements of the halo field. Using the QUIJOTE-PNG simulations, we quantify the information content accessible with measurements of the halo power spectrum monopole and quadrupole, the matter power spectrum, the halo-matter cross spectrum and the halo bispectrum monopole. This analysis is the first to include small, non-linear scales, up to $k_\mathrm{max}=0.5 \mathrm{h/Mpc}$, and to explore whether these scales can break degeneracies with cosmological and nuisance parameters making u…
Dark Matter Contraction and the Stellar Content of Massive Early-type Galaxies: Disfavoring "Light" Initial Mass Functions
我们使用恒星动力学,强透镜,恒星星族合成模型,和弱透镜剪切测量约束的暗物质(DM)的配置文件和恒星质量在一个样本的53个大规模的早型星系。我们探索了三种DM晕模型(未扰动Navarro Frenk & White [NFW]晕和Blumenthal和Gnedin的绝热收缩模型),并对恒星和维里质量之间的关系施加了一个模型(即,作为晕质量函数的恒星形成效率的关系)。我们表明,考虑到我们的模型假设,数据显然更喜欢Salpeter样的初始质量函数(IMF),而不是更轻的IMF(例如,Chabrier或Kroupa),无论选择DM晕圈。此外,我们发现数据最多倾向于适度的绝热收缩(布卢门撒尔绝热收缩是强烈不受欢迎的),并且仅与无绝热收缩一致(即,NFW晕),如果假设一个质量依赖的IMF,在这个意义上,一个更大规模的正常化的IMF更大规模的晕。
The evolution of the galaxy content of dark matter haloes
我们使用晕占据分布(HOD)框架来验证两个独立的星系形成模型对星系中暗物质晕含量及其随红移的演化的预测。我们的星系样本对应于由恒星质量和跨度$0 \le z \le 3$定义的固定数量密度范围。我们发现模型预测之间存在显著的相似性。差异出现在低星系数密度是敏感的热晕加热的活动星系核的治疗。HOD形式的演变可以用一种相对简单的方式来描述,我们使用其在$z=0$的值和一个附加的演变参数来模拟每个HOD参数。特别是,我们发现,之间的比率的特征晕质量托管中心和卫星星系可以作为一个敏感的诊断星系演化模型。我们的研究结果可以用来测试和发展星系演化的经验研究,并可以促进未来调查的模拟星系目录的建设。
Motivated by previous findings that the magnitude gap between certain satellite galaxy and the central galaxy can be used to improve the estimation of halo mass, we carry out a systematic study of the information content of different member galaxies in the modelling of the host halo mass using a machine learning approach. We employ data from the hydrodynamical simulation IllustrisTNG and train a Random Forest (RF) algorithm to predict a halo mass from the stellar masses of its member galaxies. Exhaustive feature selection is adopted to disentangle the importances of different galaxy members. W…
Galaxy clusters have been found to host a range of diffuse, non-thermal emission components, generally with steep, power law spectra. In this work we report on the detection and follow-up of radio halos, relics, remnant radio galaxies, and other fossil radio plasmas in Southern Sky galaxy clusters using the Murchison Widefield Array and the Australian Square Kilometre Array Pathfinder. We make use of the frequency coverage between the two radio interferometers - from 88 to $\sim 900$ MHz - to characterise the integrated spectra of these sources within this frequency range. Highlights from the …
Influence of baryons on the orbital structure of dark matter haloes
我们使用一套最先进的高分辨率宇宙学流体动力学模拟--超大规模模拟(OverWhelmingly Large Simulations,OWLS),研究了在形成过程中由重子在暗物质晕上留下的动力学特征.我们提出了一个详细的研究实施反馈处方的影响,轨道上的暗物质粒子,恒星粒子和subhaloes,分析运行没有反馈,与恒星的反馈和反馈从超大质量黑洞。我们关注的是在z = 0(2)时维里质量约为6 x 10^{13}(~ 7 x 10^{11})Msun/h的晕的中心区域(0. 25 r_{200})。我们还研究了这些晕的轨道内容(不同轨道类型的相对分数)如何取决于几个关键参数,如它们的质量,红移和动力学状态。这些模拟的轨道内容的频谱分析的结果进行了比较,并量化的盒,管和不规则轨道的分数的变化。在宇宙学模拟中发现盒形轨道支配着暗物质晕的轨道结构。盒子轨道的分数与中心重子分数之间有很强的相关性。虽然辐射冷却的作用,以减少部分的盒子轨道,强反馈的实施结果在一个类似的轨道分布的暗物质唯一的情况。恒星粒子所描述的轨道内容被发现是非常相似的,从暗物质粒子的轨道,这表明,要么他们已经忘记了自己的动力学历史,或者说,subhaloes带来的恒星是没有偏见的主要分布方面显着。的subhaloes的轨道内容是在广泛的协议,在粒子分布的外部区域看到的。
Atomic hydrogen (H I) gas, mostly residing in dark matter halos after cosmic reionization, is the fuel for star formation. Its relation with properties of host halo is the key to understand the cosmic H I distribution. In this work, we propose a flexible, empirical model of H I-halo relation. In this model, while the H I mass depends primarily on the mass of host halo, there is also secondary dependence on other halo properties. We apply our model to the observation data of the Arecibo Fast Legacy ALFA Survey (ALFALFA), and find it can successfully fit to the cosmic H I abundance ($Ω_{\rm HI}$…
We explore the potential of the kinetic Sunyaev-Zel'dovich (kSZ) effect as the cornerstone of a future observational probe for halo spin bias, the secondary dependence of halo clustering on halo spin at fixed halo mass. Using the IllustrisTNG magneto-hydrodynamical cosmological simulation, we measure both the kSZ and the thermal SZ (tSZ) effects produced by the baryonic content of more than 50,000 haloes within the halo mass range $11 < \log_{10} ({\rm M_{vir}}/ h^{-1} {\rm M_{\odot}}) \lesssim 14.5$. First, we confirm that the magnitude of both effects depends strongly on the total gas and vi…
Using hydrodynamical simulations, we study how well the underlying gravitational potential of a galaxy cluster can be modelled dynamically with different types of tracers. In order to segregate different systematics and the effects of varying estimator performances, we first focus on applying a generic minimal assumption method (oPDF) to model the simulated haloes using the full 6-D phasespace information. We show that the halo mass and concentration can be recovered in an ensemble unbiased way, with a stochastic bias that varies from halo to halo, mostly reflecting deviations from steady stat…
Evolution in the H I Gas Content of Galaxy Groups: Pre-Processing and Mass Assembly in the Current Epoch
我们提出了一个分析的中性氢(HI)的含量和分布的星系群作为其母暗物质晕质量的函数。Arecibo Legacy Fast ALFA巡天alpha.40数据的发布使我们能够首次研究SDSS和ALCOFA巡天中共有的740多个星系群的HI特性。我们根据现有的星等/体积受限的SDSS DR 7组/簇目录为ALCAFA HI检测分配了组成员资格。此外,我们分配组“接近”成员HI检测对象的光学对应物低于限制光学星等-从而没有实质性的贡献组恒星质量的估计,但显着的总组HI质量。我们发现,只有25%的HI检测到的星系居住在集团或集群,在大约一半的光学检测到的星系。此外,我们绘制的相对位置的光学和HI检测组作为母暗物质晕质量的函数,揭示了强有力的证据表明,HI正在处理的星系作为一个结果的组环境:随着光学成员的增加,星系团的中心越来越缺乏HI丰富的星系,最大质量星系团中星系的HI分布开始类似于在星系团中观察到的分布。比较极端的集群环境。我们发现,最低HI质量的对象失去他们的气体首先,因为他们是在集团环境中处理,这是显而易见的,富气体的对象的下降是重要的继续增长的大尺度结构在本时代,补充中性气体供应集团。最后,我们将我们的结果与宇宙学模拟的结果进行了比较,发现目前的模型不能同时预测低质量和高质量晕的HI选择晕占据分布。
There are hints suggesting that properties of galaxy populations in dark matter haloes may depend on their large-scale environment. Recent works point out that very low-density environments influence halo occupation distribution (HOD), however there is not a similar analysis focused on high-density environments. Here we use a simulated set of future virialized superstructures (FVS) to analyse the occupation of galaxies in haloes within these high globally dense regions. We use a publicly available simulated galaxy set constructed with a semi-analytical model to identify FVS in the simulation. …
International Centre for Radio Astronomy Research, The University of Western Australia(西澳大利亚大学国际射电天文研究中心);Australia Telescope National Facility, CSIRO Space & Astronomy(CSIRO空间与天文学部澳大利亚望远镜国家设施);Center for Astrophysics | Harvard & Smithsonian(哈佛-史密森尼天体物理中心)
Halos of similar mass and redshift exhibit a large degree of variability in their differential properties, such as dark matter, hot gas, and stellar mass density profiles. This variability is an indicator of diversity in the formation history of these dark matter halos that is reflected in the coupling of scatters about the mean relations. In this work, we show that the strength of this coupling depends on the scale at which halo profiles are measured. By analyzing the outputs of the IllustrisTNG hydrodynamical cosmological simulations we report the radial- and mass-dependent couplings between…
Galaxies and groups of galaxies exist in dark-matter halos filled with diffuse gas. The diffuse gas represents up to 80\% of the mass in baryonic matter within the halos(1,2), but is difficult to detect because of its low density (particle number densities of $\lesssim10^{-4}$\,cm$^{-3}$) and high temperature (mostly greater than $10^{6}$\,K). Here we analyze the impact of diffuse gas associated with nearby galaxies using the dispersion measures (DMs) of extragalactic fast radio bursts (FRBs). FRB DMs provide direct measurements of the total ionized-gas contents along their sightlines. Out of …