(Abridged for arXiv)We investigate the properties of halos, galaxies and blackholes to z=0 in the high resolution hydrodynamical simulation MassiveBlack-II (MBII) which evolves a LCDM cosmology in a comoving volume Vbox=100(Mpc/h)^3. MBII is the highest resolution simulation of this size which includes a self-consistent model for star formation, black hole accretion and associated feedback. We provide a simulation browser web application which enables interactive search and tagging of halos, subhalos and their properties and publicly release our galaxy catalogs. Our analysis of the halo mass function (MF) in MBII reveals that baryons have strong effects, with changes in the halo abundance of 20-35% below the knee of the MF (Mhalo < 10^13.2 Msun/h at z=0) when compared to fits based on dark matter only simulations. We provide a fitting function for the halo MF out to redshift z=11 and discuss how the onset of non-universality in the MF limits the accuracy of our fit. We study the halo occupation distribution and clustering of galaxies, in particular the evolution and scale dependence of stochasticity and bias finding reasonable agreement with observational data. The shape of the cosmic spectral energy distribution predicted by MBII is consistent with observations, but lower in amplitude. The Galaxy Stellar Mass Function (GSMF) function is broadly consistent with observations at z>=2. At z<2, the population of passive low mass (for M*<10^9 Msun) galaxies in MBII makes the GSMF too steep compared to observations whereas at the high mass end (M*>10^11 Msun) galaxies hosting bright AGNs make significant contributions to the GSMF. The quasar bolometric luminosity function is also largely consistent with observations. We note however that more efficient AGN feedback (beyond simple thermal coupling used here) is likely necessary for the largest, rarest objects/clusters at low redshifts.
We study the alignments of satellite galaxies, and their anisotropic distribution, with respect to location and orientation of their host central galaxy in MassiveBlack-II and IllustrisTNG simulations. We find that: the shape of the satellite system in halos of mass ($> 10^{13}h^{-1}M_{\odot}$) is well aligned with the shape of the central galaxy at $z=0.06$ with the mean alignment between the major axes being $\sim Δθ= 12^{\circ}$ when compared to a uniform random distribution; that satellite galaxies tend to be anisotropically distributed along the major axis of the central galaxy with a str…
Multiplicity functions of quasars: Predictions from the MassiveBlackII simulation
我们研究了多个活动星系核系统(三重和四重,特别是)的\texttt{MassiveBlackII}模拟的红移范围内的$0.06\lesssim z \lesssim 4$。我们在不同的尺度(由成员活动星系核之间的最大距离定义)下识别活动星系核系统(具有热光度$L_{\mathrm{bol}}>10^{42}~\mathrm{ergs/sec}$),以确定活动星系核的多重性函数。这被定义为每单位\textit{richness} $R$的活动星系核系统的体积/表面密度,即一个系统中活动星系核的数量。我们发现,引力约束的多个活动星系核系统倾向于填充尺度的$\lesssim0.7~\mathrm{cMpc}/h$,这对应于角分离的$\lesssim100~\mathrm{arcsec}$和视线速度差$\lesssim200~\mathrm{km/sec}$。模拟包含$\sim 10$和$\sim100$三重/四重每$\mathrm{deg}^2$高达深度DESI($g\lesssim24$)和LSST($g\lesssim26$)成像分别;至少$20\%$这些应该是可检测的光谱调查。模拟的类星体($L_{\mathrm{bol}}>10^{44}~\mathrm{ergs/sec}$)三重态和四重态主要存在于$1.5\lesssim z \lesssim 3$。它们的成员具有黑洞质量$1…
The First Systematic Survey of Stellar Halos in High-Inclination Galaxies Reveals Unusually Quiescent Merger Histories of Nearby Galaxies
University of Science and Technology of China(中国科学技术大学);Shanghai Jiao Tong University(上海交通大学);University of Oxford(牛津大学);Instituto de Astrofísica de Canarias(加那利天体物理研究所);Universidad de La Laguna(拉各拉纳大学)
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…
In this paper, we consider the problem of the evolution of the disk subsystem of galaxies in view of the halo. To this end, we have studied the dependence of the evolution of a non-linearly non-radially disk oscillating in its plane depending on the basic parameters of the dark matter halo numerically. The dark matter halo stabilizes the instabilities in the plane of the disk, but destabilizes its vertical oscillations. The global disk structure is dependent strongly on the mass and shape of the of dark matter halo. The evolutionary dependence of the oscillation process of a self-gravitating d…
The stellar-to-halo mass relation for Local Group galaxies
我们认为,一个单一的幂律晕质量分布是适当的直接匹配到所观察到的本群矮星系的恒星质量,允许确定的斜率的恒星质量晕质量关系的低质量星系。晕群众的错误被定义为泊松噪声的模拟本地组实现,我们确定使用受约束的本地宇宙模拟(CLUES)。对于恒星质量范围10 $^7$ <M*<10 $^8$ M $_\odot$,我们可能有一个完整的普查观测星系,我们发现,恒星质量晕质量关系遵循幂律与斜率为3.1,显着陡峭比大多数值在文献中。恒星质量和晕质量之间的陡峭关系表明,本星系群矮星系由质量范围较小的暗物质晕构成。我们的方法是强大的恒星质量的人口普查所观察到的本星系群星系是完整的,但显着的不确定性,在目前测得的斜率的恒星晕质量关系将显着降低,如果本星系群的完整性限制是$10^{6.5}$ M $\odot$或以下,突出了这样的限制,以较低的质量和较大的体积的重要性。
It has been suggested that the central stellar velocity dispersion of galaxies can trace dark matter halo mass directly. We test this hypothesis using a complete spectroscopic sample of isolated galaxies surrounded by faint satellite galaxies from the Sloan Digital Sky Survey Data Release 12. We apply a friends-of-friends algorithm with projected linking length $ΔD < 100$ kpc and radial velocity linking length $ΔV < 1000$ km s$^{-1}$ to construct our sample. Our sample includes 2807 isolated galaxies with 3417 satellite galaxies at $0.01 < z < 0.14$. We divide the sample into two groups based …
Based on galaxies in the Sloan Digital Sky Survey Data Release 7 (SDSS DR7) and dark matter haloes in the dark matter only, cosmological and constrained ELUCID simulation, we investigate the relation between the observed radii of central galaxies with stellar mass $\gtrsim 10^{8} h^{-2}{\rm M}_\odot$ and the virial radii of their host dark matter haloes with virial mass $\gtrsim 10^{10.5} h^{-1}{\rm M}_\odot$, and the dependence of galaxy-halo size relation on the halo spin and concentration. Galaxies in observation are matched to dark matter (sub-)haloes in the ELUCID simulation using a novel…
Halo mass, star formation, and morphology in galaxies: A morphology-dependent connection between halo environment and star formation activity
Instituto de Fisica de Cantabria (CSIC-Universidad de Cantabria)(坎塔布里亚物理研究所(西班牙科学研究中心-坎塔布里亚大学));University of Southampton(南安普顿大学);National Observatory of Athens(雅典国家天文台)
We use galaxies from the IllustrisTNG, MassiveBlack-II and Illustris hydrodynamic simulations to investigate the behaviour of large scale galaxy intrinsic alignments. Our analysis spans four redshift slices over the approximate range of contemporary lensing surveys $z=0-1$. We construct comparable weighted samples from the three simulations, which we then analyse using an alignment model that includes both linear and quadratic alignment contributions. Our data vector includes galaxy-galaxy, galaxy-shape and shape-shape projected correlations, with the joint covariance matrix estimated analytic…