We present for the first time the outcomes of a cosmological N-body simulation that simultaneously implements a Warm Dark Matter (WDM) particle candidate and a modified gravitational interaction in the form of $f(R)$ gravity, and compare its results with the individual effects of these two independent extensions of the standard $Λ$CDM scenario, and with the reference cosmology itself. We consider a rather extreme value of the WDM particle mass ($m_{\rm WDM}=0.4$ keV) and a single realisation of $f(R)$ gravity with $|\bar{f}_{R0}|=10^{-5}$, and we investigate the impact of these models and of their combination on a wide range of cosmological observables with the aim to identify possible observational degeneracies. In particular, we focus on the large-scale matter distribution, as well as on the statistical and structural properties of collapsed halos and cosmic voids. Differently from the case of combining $f(R)$ gravity with massive neutrinos -- previously investigated in Baldi et al. (2014) -- we find that most of the considered observables do not show any significant degeneracy due to the fact that WDM and $f(R)$ gravity are characterised by individual observational footprints with a very different functional dependence on cosmic scales and halo masses. In particular, this is the case for the nonlinear matter power spectrum in real space, for the halo and sub-halo mass functions, for the halo density profiles and for the concentration-mass relation. However, other observables -- like e.g. the halo bias -- do show some level of degeneracy between the two models, while a very strong degeneracy is observed for the nonlinear matter power spectrum in redshift space, for the density profiles of small cosmic voids -- with radius below $\approx 5$ Mpc$/h$ -- and for the voids abundance as a function of the void core density.
The number density of small dark matter (DM) halos hosting faint high-redshift galaxies is sensitive to the DM free-streaming properties. However, constraining these DM properties is complicated by degeneracies with the uncertain baryonic physics governing star formation. In this work, we use a flexible astrophysical model and a Bayesian inference framework to analyse ultra-violet (UV) luminosity functions (LFs) at z=6-8. We vary the complexity of the galaxy model (single vs double power law for the stellar -- halo mass relation) as well as the matter power spectrum (cold DM vs thermal relic w…
Upcoming ground and space-based experiments may have sufficient accuracy to place significant constraints upon high-redshift star formation, Reionization, and dark matter (DM) using the global 21-cm signal of the intergalactic medium. In the early universe, when the relative abundance of low-mass DM halos is important, measuring the global signal would place constraints on the damping of structure formation caused by DM having a higher relic velocity (warm dark matter, or WDM) than in cold dark matter (CDM). Such damping, however, can be mimicked by altering the star formation efficiency (SFE)…
Reducing cosmological degeneracies by combining multiple classes of LISA gravitational-wave standard sirens
Université de Toulouse（图卢兹大学）；Università di Milano - Bicocca（米兰比可卡大学）；INFN, Sezione di Milano-Bicocca（意大利国家核物理研究所米兰-比可卡分部）；Max-Planck-Institut für Gravitationsphysik, Albert-Einstein-Institut（马克斯·普朗克引力物理研究所爱因斯坦研究所）；SISSA（的里雅斯特高等研究学院）；INFN Sezione di Trieste（意大利国家核物理研究所的里雅斯特分部）；IFPU - Institute for Fundamental Physics of the Universe（宇宙基础物理研究所）；CERN（欧洲核子研究中心）；Université de Genève（日内瓦大学）；Università di Pisa（比萨大学）；INFN, Sezione di Pisa（意大利国家核物理研究所比萨分部）
We present the first suite of cosmological N-body simulations that simultaneously include the effects of two different and theoretically independent extensions of the standard $Λ$CDM cosmological scenario - namely an $f(R)$ theory of Modified Gravity (MG) and a cosmological background of massive neutrinos - with the aim to investigate their possible observational degeneracies. We focus on three basic statistics of the large-scale matter distribution, more specifically the nonlinear matter power spectrum, the halo mass function, and the halo bias, for which we determine the deviation with respe…
In warm dark matter scenarios structure formation is suppressed on small scales with respect to the cold dark matter case, reducing the number of low-mass halos and the fraction of ionized gas at high redshifts and thus, delaying reionization. This has an impact on the ionization history of the Universe and measurements of the optical depth to reionization, of the evolution of the global fraction of ionized gas and of the thermal history of the intergalactic medium, can be used to set constraints on the mass of the dark matter particle. However, the suppression of the fraction of ionized mediu…
Joint Constraints on Fuzzy and Warm Dark Matter from Satellite Populations of the Milky Way and Andromeda
National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；School of Astronomy and Space Sciences, University of Chinese Academy of Sciences（中国科学院大学天文与空间科学学院）；Science Center for Chinese Space Station Survey Telescope, National Astronomical Observatories, Chinese Academy of Science（中国科学院国家天文台中国空间站巡天望远镜科学中心）；School of Physics and Technology, Wuhan University（武汉大学物理科学与技术学院）
Interacting dark energy models have been suggested as alternatives to the standard cosmological model, $Λ$CDM. We focus on a phenomenologically interesting class of dark scattering models that is characterised by pure momentum exchange between dark energy and dark matter. This model extends the parameter space with respect to $Λ$CDM by two parameters, $w$ and $A$, which define the dark energy equation of state and the strength of the coupling between dark energy and dark matter, respectively. In order to test non-standard cosmologies with Stage-IV galaxy clustering surveys, it is crucial to mo…
Mapping the Information Geometry of an Unresolved Dark Matter Population using a Differentiable Strong Lensing Simulator
Université de Montréal（蒙特利尔大学）；Mila - Quebec Artificial Intelligence Institute（魁北克人工智能研究所米拉）；Ciela - Montreal Institute for Astrophysical Data Analysis and Machine Learning（蒙特利尔天体物理数据分析与机器学习研究所）
The James Webb Space Telescope (JWST) will revolutionise our understanding of early galaxy formation, and could potentially set stringent constraints on the nature of dark matter. We use a semi-empirical model of galaxy formation to investigate the extent to which uncertainties in the implementation of baryonic physics may be degenerate with the predictions of two different models of dark matter -- Cold Dark Matter (CDM) and a 7 keV sterile neutrino, which behaves as Warm Dark Matter (WDM). Our models are calibrated to the observed UV luminosity function at $z=4$ using two separate dust attenu…
We present a field-based approach to the analysis of cosmic shear data to infer jointly cosmological parameters and the dark matter distribution. This forward modelling approach samples the cosmological parameters and the initial matter fluctuations, using a physical gravity model to link the primordial fluctuations to the non-linear matter distribution. Cosmological parameters are sampled and updated consistently through the forward model, varying (1) the initial matter power spectrum, (2) the geometry through the distance-redshift relationship, and (3) the growth of structure and light-cone …
The nature of the dark matter can affect the collapse time of dark matter haloes, and can therefore be imprinted in observables such as the stellar population ages and star formation histories of dwarf galaxies. In this paper we use high resolution hydrodynamical simulations of Local Group-analogue (LG) volumes in cold dark matter (CDM), sterile neutrino warm dark matter (WDM) and self-interacting dark matter (SIDM) models with the EAGLE galaxy formation code to study how galaxy formation times change with dark matter model. We are able to identify the same haloes in different simulations, sin…
Star-forming galaxies are a highly biased tracer of the underlying dark matter density field. Their clustering can be studied through the cosmic infrared background anisotropies. These anisotropies have been measured from 100 \mum to 2 mm in the last few years. In this paper, we present a fully parametric model allowing a joint analysis of these recent observations. In order to develop a coherent model at various wavelengths, we rely on two building blocks. The first one is a parametric model that describes the redshift evolution of the luminosity function of star-forming galaxies. It compares…
We use a semi-analytic model, ${\it Delphi}$, that jointly tracks the dark matter and baryonic assembly of high-redshift ($z \simeq 4-20$) galaxies to gain insight on the number density of Direct Collapse Black Hole (DCBH) hosts in three different cosmologies: the standard Cold Dark Matter (CDM) model and two Warm Dark Matter (WDM) models with particle masses of 3.5 and 1.5 keV. Obtaining the Lyman-Werner (LW) luminosity of each galaxy from ${\it Delphi}$, we use a clustering bias analysis to identify all, pristine halos with a virial temperature $T_{vir}>=10^4$ K that are irradiated by a LW b…
We present new measurements of the free-streaming of warm dark matter (WDM) from Lyman-$α$ flux-power spectra. We use data from the medium resolution, intermediate redshift XQ-100 sample observed with the X-shooter spectrograph ($z=3 - 4.2$) and the high-resolution, high-redshift sample used in Viel et al. (2013) obtained with the HIRES/MIKE spectrographs ($z=4.2 - 5.4$). Based on further improved modelling of the dependence of the Lyman-$α$ flux-power spectrum on the free-streaming of dark matter, cosmological parameters, as well as the thermal history of the intergalactic medium (IGM) with h…
We have considered the prospects for measuring the cross Warm Dark Matter (WDM) power spectrum of the redshifted HI 21-cm signal and the Lyman-$α$ forest and thereby constraining WDM mass using observations with upcoming radio-interferometers - the Ooty Wide Field Array (OWFA) and SKA1-mid, and a spectroscopic survey of the quasars. We have considered a quasar survey with a mean observed quasar number density of $\bar{\rm n}_{\rm Q} = 48$ deg$^{-2}$ over a collecting area of 14455 deg$^{2}$, and a mean spectroscopic SNR = 5. Our analysis with OWFA shows that it is possible to measure the WDM p…
Exploring Joint Observation of the CSST Shear and clustering of astrophysical gravitational wave source measurements
National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；School of Astronomy and Space Sciences, University of Chinese Academy of Sciences(UCAS)（中国科学院大学天文与空间科学学院）
Disentangling the Halo: Joint Model for Measurements of the Kinetic Sunyaev-Zeldovich Effect and Galaxy-Galaxy Lensing
Princeton University（普林斯顿大学）；Cornell University（康奈尔大学）；Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）；University of California, Berkeley（加州大学伯克利分校）；Stanford University（斯坦福大学）
We conduct a pseudo-$C_\ell$ analysis of the tomographic cross-correlation between 1000 deg$^2$ of weak lensing data from the Kilo-Degree Survey (KiDS-1000) and the thermal Sunyaev-Zeldovich (tSZ) effect measured by Planck and the Atacama Cosmology Telescope (ACT). Using HMx, a halo-model-based approach that consistently models the gas, star, and dark matter components, we are able to derive constraints on both cosmology and baryon feedback for the first time from these data, marginalising over redshift uncertainties, intrinsic alignment of galaxies, and contamination by the cosmic infrared ba…
Detecting the thermal and non-thermal emission from the shocked cosmic gas surrounding large-scale structures represents a challenge for observations, as well as a unique window into the physics of the warm-hot intergalactic medium. In this work, we present synthetic radio and X-ray surveys of large cosmological simulations in order to assess the chances of jointly detecting the cosmic web in both frequency ranges. We then propose best observing strategies tailored for existing (LOFAR, MWA and XMM) or future instruments (SKA-LOW and SKA-MID, ATHENA and eROSITA). We find that the most promising…
JWST lensed quasar dark matter survey IV: Stringent warm dark matter constraints from the joint reconstruction of extended lensed arcs and quasar flux ratios
University of Chicago（芝加哥大学）；University of California, Merced（加州大学默塞德分校）；University of California, Los Angeles（加州大学洛杉矶分校）；Stony Brook University（石溪大学）；Carnegie Institution for Science（卡内基科学机构）；University of California, Davis（加州大学戴维斯分校）；The University of Tokyo（东京大学）
The elastic scattering between dark matter particles and radiation represents an attractive possibility to solve a number of discrepancies between observations and standard cold dark matter predictions, as the induced collisional damping would imply a suppression of small-scale structures. We consider this scenario and confront it with measurements of the ionization history of the Universe at several redshifts and with recent estimates of the counts of Milky Way satellite galaxies. We derive a conservative upper bound on the dark matter-photon elastic scattering cross section of $σ_{γ\rm{DM}} …
Locating the missing baryons in the warm-hot intergalactic medium with fast radio bursts and the Sunyaev-Zel'dovich effect
School of Astronomy and Space Science, Nanjing University（南京大学天文与空间科学学院）；Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education（教育部现代天文与天体物理重点实验室（南京大学））；Department of Astronomy, School of Physical Sciences, University of Science and Technology of China（中国科学技术大学物理科学学院天文学系）；Center for Cosmology and Computational Astrophysics, Zhejiang University（浙江大学宇宙学与计算天体物理中心）
Revisiting holographic dark energy from the perspective of multi-messenger gravitational wave astronomy: future joint observations with short gamma-ray bursts
Joint constraints on gravity and stellar orbital anisotropy in massive galaxies
Shanghai Normal University（上海师范大学）；National Astronomical Observatories, Chinese Academy of Science（中国科学院国家天文台）；Purple Mountain Observatory, Chinese Academy of Science（中国科学院紫金山天文台）；South-Western Institute for Astronomy Research, Yunnan University（云南大学西南天文研究所）；Shanghai Astronomical Observatory, Chinese Academy of Science（中国科学院上海天文台）
