A viable alternative to the dark energy as a solution of the cosmic speed up problem is represented by Extended Theories of Gravity. Should this be indeed the case, there will be an impact not only on cosmological scales, but also at any scale, from the Solar System to extragalactic ones. In particular, the gravitational potential can be different from the Newtonian one commonly adopted when computing the circular velocity fitted to spiral galaxies rotation curves. Phenomenologically modelling the modified point mass potential as the sum of a Newtonian and a Yukawa like correction, we simulate observed rotation curves for a spiral galaxy described as the sum of an exponential disc and a NFW dark matter halo. We then fit these curves assuming parameterized halo models (either with an inner cusp or a core) and using the Newtonian potential to estimate the theoretical rotation curve. Such a study allows us to investigate the bias on the disc and halo model parameters induced by the systematic error induced by forcing the gravity theory to be Newtonian when it is not. As a general result, we find that both the halo scale length and virial mass are significantly overestimated, while the dark matter mass fraction within the disc optical radius is typically underestimated. Moreover, should the Yukawa scale length be smaller than the disc half mass radius, then the logarithmic slope of the halo density profile would turn out to be shallower than the NFW one. Finally, cored models are able to fit quite well the simulated rotation curves, provided the disc mass is biased high in agreement with the results in literature, favoring cored haloes and maximal discs. Such results make us argue that the cusp/core controversy could actually be the outcome of an incorrect assumption about which theory of gravity must actually be used in computing the theoretical circular velocity.
Secondary halo bias, commonly known as 'assembly bias,' is the dependence of halo clustering on a halo property other than mass. This prediction of the Lambda-Cold Dark Matter cosmology is essential to modelling the galaxy distribution to high precision and interpreting clustering measurements. As the name suggests, different manifestations of secondary halo bias have been thought to originate from halo assembly histories. We show conclusively that this is incorrect for cluster-size haloes. We present an up-to-date summary of secondary halo biases of high-mass haloes due to various halo proper…
Orbital parameters of infalling satellite haloes in the hierarchical $Λ$CDM model
本文给出了质量范围为$10^{12}-10^{14}$ M $_\odot$的$Λ$ CDM晕坠落卫星的轨道参数分布，它代表了宿主晕内部子结构随后演化的初始条件。我们使用合并树构造在一个高分辨率的宇宙学N体模拟跟踪卫星晕，并确定的时间。我们发现显着的趋势与主机晕质量和卫星的主机晕质量的比例的轨道参数的分布。对于所有的主机晕质量，卫星的落质量是一个较大的分数的主机晕质量有更多的偏心，径向偏置的轨道。在固定的卫星与宿主晕质量比，高质量的晕偏向于吸积卫星上稍微更径向轨道。为了充分表征轨道分布，需要拟合两个选定的轨道参数（例如径向和切向速度或能量和角动量）的相关二元分布。我们提供了简单的适合一个选择的二元分布，当忠实地转换，捕捉任何预测的一维分布的行为。
We introduce the TangoSIDM project, a suite of cosmological simulations of structure formation in a $Λ$-Self-Interacting Dark Matter (SIDM) universe. TangoSIDM explores the impact of large dark matter (DM) scattering cross sections over dwarf galaxy scales. Motivated by DM interactions that follow a Yukawa potential, the cross section per unit mass, $σ/m_χ$, assumes a velocity dependent form that avoids violations of current constraints on large scales. We demonstrate that our implementation accurately models not only core formation in haloes, but also gravothermal core collapse. For central h…
We investigate the role of angular momentum in the clustering of dark matter haloes. We make use of data from two high-resolution N-body simulations spanning over four orders of magnitude in halo mass, from $10^{9.8}$ to $10^{14}\ h^{-1}\ \text{M}_\odot$. We explore the hypothesis that mass accretion in filamentary environments alters the angular momentum of a halo, thereby driving a correlation between the spin parameter $λ$ and the strength of clustering. However, we do not find evidence that the distribution of matter on large scales is related to the spin of haloes. We find that a halo's s…
In this work we aim at investigating the effects of baryons on the dark matter (DM) haloes structure, focusing on the correlation between the presence and importance of stellar discs and the halo shapes. We study the properties of a subsample of DM haloes from Fenix and EAGLE cosmological simulations. We inspect the central regions of haloes in the mass range [10.9 - 992.3] x 10^{10} Msun at z=0, comparing the hydrodynamic runs and their dark matter only (DMo) counterparts. Our results indicate that baryons have a significant impact on the shape of the inner halo, mainly within ~ 20 percent of…
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。
Cosmological N-body simulations have been a major tool of theorists for decades, yet many of the numerical issues that these simulations face are still unexplored. This paper measures numerical biases in these large, dark matter-only simulations that affect the properties of their dark matter haloes. We compare many simulation suites in order to provide several tools for simulators and analysts which help mitigate these biases. We summarise our comparisons with practical `convergence limits' that can be applied to a wide range of halo properties, including halo properties which are traditional…
We estimate the detectability of X-ray metal-line emission from the circumgalactic medium (CGM) of galaxies over a large halo mass range ($\mathrm{M}_{\mathrm{200c}} = 10^{11.5}$-$10^{14.5}\,\mathrm{M}_{\odot}$) using the EAGLE simulations. With the XRISM Resolve instrument, a few bright (K-$α$ or Fe L-shell) lines from $\mathrm{M}_{\mathrm{200c}} \gtrsim 10^{13}\,\mathrm{M}_{\odot}$ haloes should be detectable. Using the Athena X-IFU or the Lynx Main Array, emission lines (especially from O VIII and O VII) from the inner CGM of $\mathrm{M}_{\mathrm{200c}} \gtrsim10^{12.5}\,\mathrm{M}_{\odot}$…
We present improved modelling of the redshift-space distortions of galaxy clustering that arise from peculiar velocities. We create mock galaxy catalogues in the framework of the halo model, using data from the Bolshoi project. These mock galaxy populations are inserted into the haloes with additional degrees of freedom that govern spatial and kinematical biases of the galaxy populations relative to the dark matter. We explore this generalised halo model with an MCMC algorithm, comparing the predictions to data from the Galaxy And Mass Assembly (GAMA) survey, and thus derive one of the first c…
Systematic uncertainties in the mass measurement of galaxy clusters limit the cosmological constraining power of future surveys that will detect more than $10^5$ clusters. Previously, we argued that aperture masses can be inferred more accurately and precisely than 3D masses without loss of cosmological constraining power. Here, we use the Baryons and Haloes of Massive Systems (BAHAMAS) cosmological, hydrodynamical simulations to show that aperture masses are also less sensitive to changes in mass caused by galaxy formation processes. For haloes with $m_\mathrm{200m,dmo} > 10^{14} \, h^{-1} \,…
We study the Voronoi volume function (VVF) -- the distribution of cell volumes (or inverse local number density) in the Voronoi tessellation of any set of cosmological tracers (galaxies/haloes). We show that the shape of the VVF of biased tracers responds sensitively to physical properties such as halo mass, large-scale environment, substructure and redshift-space effects, making this a hitherto unexplored probe of both primordial cosmology and galaxy evolution. Using convenient summary statistics -- the width, median and a low percentile of the VVF as functions of average tracer number densit…
Cosmic variance of the galaxy cluster weak lensing signal
固定质量星系团投影密度剖面的内禀变化是星系团弱透镜不确定性的一个来源。我们提出了一个半分析模型来解释这种效应，基于晕浓度，椭圆度和方向的变化，以及相关晕的存在。我们在10%的水平上校准了我们模型的参数，以匹配M_200 m = 10^14时星系团轮廓的经验宇宙方差。10^15 h ^-1 M_sol，z = 0.25. 0.5在宇宙学模拟中。我们表明，弱透镜测量集群显着低估质量的不确定性，如果内在的轮廓变化被忽略，我们的模型可以用来提供正确的质量可能性。对于质量最大的星系团和深层观测（在M_200 m = 10^15 h ^-1 M_sol和z = 0.25时，仅宇宙方差的不确定性就有约20%），弱透镜星系团质量测量的可实现精度受到的影响特别大，但在典型的地面条件下也很明显。我们发现，忽略内在轮廓的变化导致的偏见，在质量可观测的关系约束与弱透镜，无论是内在的散射和整体规模（后者在15%的水平）。这些偏差超过了即将进行的调查的统计误差，如果考虑到星系团分布的宇宙方差，就可以避免这些偏差。
We quantify two main pathways through which baryonic physics biases cluster count cosmology. We create mock cluster samples that reproduce the baryon content inferred from X-ray observations. We link clusters to their counterparts in a dark matter-only universe, whose abundances can be predicted robustly, by assuming the dark matter density profile is not significantly affected by baryons. We derive weak lensing halo masses and infer the best-fitting cosmological parameters $Ω_\mathrm{m}$, $S_8=σ_8(Ω_\mathrm{m}/0.3)^{0.2}$, and $w_0$ from the mock cluster sample. We find that because of the ne…
We study the relations among the parameters of the hybrid Lagrangian bias expansion model, fitting biased auto and cross power spectra up to $k_{\rm max} = 0.7 \, h \, \mathrm{Mpc}^{-1}$. We consider $\sim 8000$ halo and galaxy samples, with different halo masses, redshifts, galaxy number densities, and varying the parameters of the galaxy formation model. Galaxy samples are obtained through state-of-the-art extended subhalo abundance matching techniques and include both stellar-mass and star-formation-rate selected galaxies. All of these synthetic galaxies samples are publicly available at ht…
Satellite galaxies are commonly used as tracers to measure the line-of-sight velocity dispersion ($σ_{\rm LOS}$) of the dark matter halo associated with their central galaxy, and thereby to estimate the halo's mass. Recent observational dispersion estimates of the Local Group, including the Milky Way and M31, suggest $σ\sim$50 km/s, which is surprisingly low when compared to the theoretical expectation of $σ\sim$100s km/s for systems of their mass. Does this pose a problem for $Λ$CDM? We explore this tension using the {\small{SURFS}} suite of $N$-body simulations, containing over 10000 (sub)ha…
Cluster gravitational redshifts: uncertainties and survey requirements
Imperial College（帝国理工学院）；Alma Mater Studiorum Universita di Bologna（博洛尼亚大学）；INAF - Osservatorio di Astrofisica e Scienza dello Spazio di Bologna（意大利国家天体物理研究所博洛尼亚天文与空间科学观测站）；INFN - Sezione di Bologna（意大利国家核物理研究所博洛尼亚分部）；Università degli Studi di Milano（米兰大学）
Euclid preparation. The shape of halo profiles in $Λ$CDM and non-standard cosmologies
Università degli Studi di Milano Bicocca（米兰比可卡大学）；INAF-Osservatorio Astronomico di Trieste（的里雅斯特天文台）；Laboratoire d’etude de l’Univers et des phenomenes eXtremes, Observatoire de Paris, Université PSL, Sorbonne Université, CNRS（极端宇宙现象研究实验室，巴黎天文台，巴黎文理研究大学，索邦大学，法国国家科学研究中心）；Institut d’Astrophysique de Paris, UMR 7095, CNRS, and Sorbonne Université（巴黎天体物理研究所，法国国家科学研究中心，索邦大学）；Université Paris-Cité（巴黎西岱大学）；University of Helsinki（赫尔辛基大学）；Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, University of Manchester（曼彻斯特大学天体物理学乔德雷尔银行中心）；Yusuf Hamied Department of Chemistry, University of Cambridge（剑桥大学尤素福·哈米德化学系）；Instituto de Física Teórica UAM-CSIC（马德里自治大学-西班牙国家科学研究委员会理论物理研究所）
Understanding the physical connection between cluster galaxies and massive haloes is key to mitigating systematic uncertainties in next-generation cluster cosmology. We develop a novel method to infer the level of conformity between the stellar mass of the brightest central galaxies~(BCGs) $M_*^{BCG}$ and the satellite richness $λ$, defined as their correlation coefficient $ρ_{cc}$ at fixed halo mass, using the abundance and weak lensing of SDSS clusters as functions of $M_*^{BCG}$ and $λ$. We detect a halo mass-dependent conformity as $ρ_{cc}{=}0.60{+}0.08\ln(M_h/3{\times}10^{14}M_{\odot}/h)$…
Euclid: Impact of halo mass-conversion model assumptions on galaxy cluster number-count analyses
Laboratoire d’etude de l’Univers et des phenomenes eXtremes, Observatoire de Paris, Université PSL, Sorbonne Université, CNRS（极端宇宙与现象实验室，巴黎天文台，巴黎文理研究大学，索邦大学，法国国家科学研究中心）；Université Paris-Cité（巴黎西岱大学）；Donostia International Physics Center (DIPC)（圣塞巴斯蒂安国际物理中心）；Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, University of Manchester（曼彻斯特大学天体物理学约德雷尔银行中心，物理与天文系）；Institut d’Astrophysique de Paris, UMR 7095, CNRS, and Sorbonne Université（巴黎天体物理学研究所，CNRS联合研究单位7095，索邦大学）；Dipartimento di Fisica e Astronomia "Augusto Righi" - Alma Mater Studiorum Università di Bologna（博洛尼亚大学阿尔玛·mater studiorum大学物理与天文学院“奥古斯托·里吉”系）；INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna（意大利国家天体物理研究所博洛尼亚天文台与空间科学部）；INFN-Sezione di Bologna（意大利国家核物理研究所博洛尼亚分部）
CHEX-MATE: AMALGAM weak-lensing analysis of 41 Planck Sunyaev-Zel'dovich-selected galaxy clusters
Academia Sinica Institute of Astronomy and Astrophysics（中央研究院天文及天文物理研究所）；Laboratoire d’Astrophysique de Marseille, Aix-Marseille Univ.（马赛天文物理实验室，艾克斯-马赛大学）；Institut d’Astrophysique de Paris, UMR 7095, CNRS & Sorbonne Université（巴黎天文物理研究所，CNRS与索邦大学）；INAF – Osservatorio di Astrofisica e Scienza dello Spazio di Bologna（意大利国家天体物理研究所博洛尼亚天文物理与空间科学观测站）；INFN, Sezione di Bologna（意大利国家核物理研究所博洛尼亚分部）；Department of Physical Science, Hiroshima University（广岛大学理学部）；Hiroshima Astrophysical Science Center, Hiroshima University（广岛大学广岛天体物理科学中心）；Core Research for Energetic Universe, Hiroshima University（广岛大学宇宙高能核心研究中心）；Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM（巴黎萨克雷大学、巴黎西岱大学、法国原子能和替代能源委员会、CNRS、AIM）；Sorbonne Université（索邦大学）
