scholarly journals The weak lensing radial acceleration relation: Constraining modified gravity and cold dark matter theories with KiDS-1000

2021 ◽  
Vol 650 ◽  
pp. A113
Author(s):  
Margot M. Brouwer ◽  
Kyle A. Oman ◽  
Edwin A. Valentijn ◽  
Maciej Bilicki ◽  
Catherine Heymans ◽  
...  

We present measurements of the radial gravitational acceleration around isolated galaxies, comparing the expected gravitational acceleration given the baryonic matter (gbar) with the observed gravitational acceleration (gobs), using weak lensing measurements from the fourth data release of the Kilo-Degree Survey (KiDS-1000). These measurements extend the radial acceleration relation (RAR), traditionally measured using galaxy rotation curves, by 2 decades in gobs into the low-acceleration regime beyond the outskirts of the observable galaxy. We compare our RAR measurements to the predictions of two modified gravity (MG) theories: modified Newtonian dynamics and Verlinde’s emergent gravity (EG). We find that the measured relation between gobs and gbar agrees well with the MG predictions. In addition, we find a difference of at least 6σ between the RARs of early- and late-type galaxies (split by Sérsic index and u − r colour) with the same stellar mass. Current MG theories involve a gravity modification that is independent of other galaxy properties, which would be unable to explain this behaviour, although the EG theory is still limited to spherically symmetric static mass models. The difference might be explained if only the early-type galaxies have significant (Mgas ≈ M⋆) circumgalactic gaseous haloes. The observed behaviour is also expected in Λ-cold dark matter (ΛCDM) models where the galaxy-to-halo mass relation depends on the galaxy formation history. We find that MICE, a ΛCDM simulation with hybrid halo occupation distribution modelling and abundance matching, reproduces the observed RAR but significantly differs from BAHAMAS, a hydrodynamical cosmological galaxy formation simulation. Our results are sensitive to the amount of circumgalactic gas; current observational constraints indicate that the resulting corrections are likely moderate. Measurements of the lensing RAR with future cosmological surveys (such as Euclid) will be able to further distinguish between MG and ΛCDM models if systematic uncertainties in the baryonic mass distribution around galaxies are reduced.

2020 ◽  
Vol 493 (1) ◽  
pp. 1361-1374 ◽  
Author(s):  
Arya Farahi ◽  
Matthew Ho ◽  
Hy Trac

ABSTRACT Cold dark matter model predicts that the large-scale structure grows hierarchically. Small dark matter haloes form first. Then, they grow gradually via continuous merger and accretion. These haloes host the majority of baryonic matter in the Universe in the form of hot gas and cold stellar phase. Determining how baryons are partitioned into these phases requires detailed modelling of galaxy formation and their assembly history. It is speculated that formation time of the same mass haloes might be correlated with their baryonic content. To evaluate this hypothesis, we employ haloes of mass above $10^{14}\, \mathrm{M}_{\odot }$ realized by TNG300 solution of the IllustrisTNG project. Formation time is not directly observable. Hence, we rely on the magnitude gap between the brightest and the fourth brightest halo galaxy member, which is shown that traces formation time of the host halo. We compute the conditional statistics of the stellar and gas content of haloes conditioned on their total mass and magnitude gap. We find a strong correlation between magnitude gap and gas mass, BCG stellar mass, and satellite galaxies stellar mass, but not the total stellar mass of halo. Conditioning on the magnitude gap can reduce the scatter about halo property–halo mass relation and has a significant impact on the conditional covariance. Reduction in the scatter can be as significant as 30 per cent, which implies more accurate halo mass prediction. Incorporating the magnitude gap has a potential to improve cosmological constraints using halo abundance and allows us to gain insight into the baryon evolution within these systems.


2020 ◽  
Vol 498 (3) ◽  
pp. 3158-3170
Author(s):  
Tianyi Yang ◽  
Michael J Hudson ◽  
Niayesh Afshordi

ABSTRACT The cold dark matter model predicts that dark matter haloes are connected by filaments. Direct measurements of the masses and structure of these filaments are difficult, but recently several studies have detected these dark-matter-dominated filaments using weak lensing. Here we study the efficiency of galaxy formation within the filaments by measuring their total mass-to-light ratios and stellar mass fractions. Specifically, we stack pairs of luminous red galaxies (LRGs) with a typical separation on the sky of 8 h−1 Mpc. We stack background galaxy shapes around pairs to obtain mass maps through weak lensing, and we stack galaxies from the Sloan Digital Sky Survey to obtain maps of light and stellar mass. To isolate the signal from the filament, we construct two matched catalogues of physical and non-physical (projected) LRG pairs, with the same distributions of redshift and separation. We then subtract the two stacked maps. Using LRG pair samples from the Baryon Oscillation Spectroscopic Survey at two different redshifts, we find that the evolution of the mass in filament is consistent with the predictions from perturbation theory. The filaments are not entirely dark: Their mass-to-light ratios (M/L = 351 ± 137 in solar units in the rband) and stellar mass fractions (Mstellar/M = 0.0073 ± 0.0030) are consistent with the cosmic values (and with their redshift evolutions).


2020 ◽  
Vol 497 (2) ◽  
pp. 2393-2417 ◽  
Author(s):  
Alexandres Lazar ◽  
James S Bullock ◽  
Michael Boylan-Kolchin ◽  
T K Chan ◽  
Philip F Hopkins ◽  
...  

ABSTRACT We analyse the cold dark matter density profiles of 54 galaxy haloes simulated with Feedback In Realistic Environments (FIRE)-2 galaxy formation physics, each resolved within $0.5{{\ \rm per\ cent}}$ of the halo virial radius. These haloes contain galaxies with masses that range from ultrafaint dwarfs ($M_\star \simeq 10^{4.5}\, \mathrm{M}_{\odot }$) to the largest spirals ($M_\star \simeq 10^{11}\, \mathrm{M}_{\odot }$) and have density profiles that are both cored and cuspy. We characterize our results using a new, analytic density profile that extends the standard two-parameter Einasto form to allow for a pronounced constant density core in the resolved innermost radius. With one additional core-radius parameter, rc, this three-parameter core-Einasto profile is able to characterize our feedback-impacted dark matter haloes more accurately than other three-parameter profiles proposed in the literature. To enable comparisons with observations, we provide fitting functions for rc and other profile parameters as a function of both M⋆ and M⋆/Mhalo. In agreement with past studies, we find that dark matter core formation is most efficient at the characteristic stellar-to-halo mass ratio M⋆/Mhalo ≃ 5 × 10−3, or $M_{\star } \sim 10^9 \, \mathrm{M}_{\odot }$, with cores that are roughly the size of the galaxy half-light radius, rc ≃ 1−5 kpc. Furthermore, we find no evidence for core formation at radii $\gtrsim 100\ \rm pc$ in galaxies with M⋆/Mhalo < 5 × 10−4 or $M_\star \lesssim 10^6 \, \mathrm{M}_{\odot }$. For Milky Way-size galaxies, baryonic contraction often makes haloes significantly more concentrated and dense at the stellar half-light radius than DMO runs. However, even at the Milky Way scale, FIRE-2 galaxy formation still produces small dark matter cores of ≃ 0.5−2 kpc in size. Recent evidence for a ∼2 kpc core in the Milky Way’s dark matter halo is consistent with this expectation.


2020 ◽  
Vol 642 ◽  
pp. A83 ◽  
Author(s):  
Andrej Dvornik ◽  
Henk Hoekstra ◽  
Konrad Kuijken ◽  
Angus H. Wright ◽  
Marika Asgari ◽  
...  

We simultaneously present constraints on the stellar-to-halo mass relation for central and satellite galaxies through a weak lensing analysis of spectroscopically classified galaxies. Using overlapping data from the fourth data release of the Kilo-Degree Survey (KiDS), and the Galaxy And Mass Assembly survey (GAMA), we find that satellite galaxies are hosted by halo masses that are 0.53 ± 0.39 dex (68% confidence, 3σ detection) smaller than those of central galaxies of the same stellar mass (for a stellar mass of log(M⋆/M⊙) = 10.6). This is consistent with galaxy formation models, whereby infalling satellite galaxies are preferentially stripped of their dark matter. We find consistent results with similar uncertainties when comparing constraints from a standard azimuthally averaged galaxy-galaxy lensing analysis and a two-dimensional likelihood analysis of the full shear field. As the latter approach is somewhat biased due to the lens incompleteness and as it does not provide any improvement to the precision when applied to actual data, we conclude that stacked tangential shear measurements are best-suited for studies of the galaxy-halo connection.


2005 ◽  
Vol 216 ◽  
pp. 140-151
Author(s):  
Henk Hoekstra

Weak gravitational lensing of distant galaxies by foreground structures has proven to be a powerful tool to study the mass distribution in the universe. The advent of panoramic cameras on 4-m class telescopes has led to a first generation of surveys that already compete with large redshift surveys in terms of the accuracy with which cosmological parameters can be determined. The next surveys, which already have started taking data, will provide another major step forward. At the current level, systematics appear under control, and it is expected that weak lensing will develop into a key tool in the era of precision cosmology, provided we improve our knowledge of the non-linear matter power spectrum and the source redshift distribution. In this review we will briefly describe the principles of weak lensing and discuss the results of recent cosmic shear surveys. We show how the combination of weak lensing and cosmic microwave background measurements can provide tight constraints on cosmological parameters. We also demonstrate the usefulness of weak lensing in studies of the relation between the galaxy distribution and the underlying dark matter distribution (“galaxy biasing”), which can provide important constraints on models of galaxy formation. Finally, we discuss new and upcoming large cosmic shear surveys.


2019 ◽  
Vol 629 ◽  
pp. L5 ◽  
Author(s):  
M. Bílek ◽  
S. Samurović ◽  
F. Renaud

We report that the density profiles of globular cluster (GC) systems in a sample of 17 early-type galaxies (ETGs) show breaks at the radii where the gravitational acceleration exerted by the stars equals the galactic acceleration scale a0 known from the radial acceleration relation or the modified Newtonian dynamics (MOND). The match with the other characteristic radii in the galaxy is not that close. We propose possible explanations in the frameworks of the Lambda cold dark matter (ΛCDM) model and MOND. We find tentative evidence that in the ΛCDM context, GCs reveal not only the masses of the dark halos through the richness of the GC systems but also the concentrations through the break radii of the GC systems.


2018 ◽  
Vol 27 (14) ◽  
pp. 1847010 ◽  
Author(s):  
Sabine Hossenfelder ◽  
Tobias Mistele

Modified Newtonian Dynamics has one free parameter and requires an interpolation function to recover the normal Newtonian limit. We here show that this interpolation function is unnecessary in a recently proposed covariant completion of Erik Verlinde’s emergent gravity, and that Verlinde’s approach moreover fixes the function’s one free parameter. The so-derived correlation between the observed acceleration (inferred from rotation curves) and the gravitational acceleration due to merely the baryonic matter fits well with data. We then argue that the redshift-dependence of galactic rotation curves could offer a way to tell apart different versions of modified gravity from particle dark matter.


2017 ◽  
Vol 13 (S334) ◽  
pp. 213-218
Author(s):  
Kyle A. Oman

AbstractThe apostle cosmological hydrodynamical simulation suite is a collection of twelve regions ~5 Mpc in diameter, selected to resemble the Local Group of galaxies in terms of kinematics and environment, and re-simulated at high resolution (minimum gas particle mass of 104 M⊙) using the galaxy formation model and calibration developed for the eagle project. I select a sample of dwarf galaxies (60 < Vmax/km s−1 < 120) from these simulations and construct synthetic spatially- and spectrally-resolved observations of their 21-cm emission. Using the 3Dbarolo tilted-ring modelling tool, I extract rotation curves from the synthetic data cubes. In many cases, non-circular motions present in the gas disc hinder the recovery of a rotation curve which accurately traces the underlying mass distribution; a large central deficit of dark matter, relative to the predictions of cold dark matter N-body simulations, may then be erroneously inferred.


2019 ◽  
Vol 488 (4) ◽  
pp. 5551-5565 ◽  
Author(s):  
Yueying Ni ◽  
Mei-Yu Wang ◽  
Yu Feng ◽  
Tiziana Di Matteo

ABSTRACT During the last decades, rapid progress has been made in measurements of the rest-frame ultraviolet (UV) luminosity function (LF) for high-redshift galaxies (z ≥ 6). The faint-end of the galaxy LF at these redshifts provides powerful constraints on different dark matter (DM) models that suppress small-scale structure formation. In this work we perform full hydrodynamical cosmological simulations of galaxy formation using an alternative DM model composed of extremely light bosonic particles (m ∼ 10−22 eV), also known as fuzzy dark matter (FDM), and examine the predictions for the galaxy stellar mass function and LF at z ≥ 6 for a range of FDM masses. We find that for FDM models with bosonic mass m = 5 × 10−22 eV, the number density of galaxies with stellar mass $\rm M_* \sim 10^7 M_{\odot }$ is suppressed by $\sim 40\, {\rm per\, cent}$ at z  = 9, $\sim 20\, {\rm per\, cent}$ at z  = 5, and the UV LFs within magnitude range of −16 < MUV < −14 is suppressed by $\sim 60\, {\rm per\, cent}$ at z = 9, $\sim 20\, {\rm per\, cent}$ at z = 5 comparing to the cold dark matter counterpart simulation. Comparing our predictions with current measurements of the faint-end LFs (−18 ≤ MUV ≤ −14), we find that FDM models with m22 < 5 × 10−22 are ruled out at 3σ confidence level. We expect that future LF measurements by James Webb Space Telescope, which will extend down to MUV ∼ −13 for z ≲ 10, with a survey volume that is comparable to the Hubble Ultra Deep Field would have the capability to constrain FDM models to m  ≳ 10−21 eV.


Limits on the anisotropy of the microwave background provide strong constraints on theories of galaxy formation which incorporate non-baryonic dark matter. We focus on scale-invariant perturbations, which may be in either an adiabatic or an isocurvature mode. Adiabatic models with cold dark matter in which galaxies trace the mass distribution lead to excessive small-scale anisotropies unless Ω 0 h4/3 0 > 0.2. This apparently conflicts with the low value of Ω 0 deduced from dynamical studies of galaxy clustering. This difficulty may be resolved if galaxies are biased tracers of the mass. Isocurvature cold dark-matter models are incompatible with observations even if Ω 0 = 1 unless the amplitude of the galaxy correlation function is more than four times that of the mass distribution. The statistics of the radiation pattern may provide a useful test of the Gaussian nature of the fluctuations.


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