scholarly journals Warm dark matter chills out: constraints on the halo mass function and the free-streaming length of dark matter with eight quadruple-image strong gravitational lenses

2019 ◽  
Vol 491 (4) ◽  
pp. 6077-6101 ◽  
Author(s):  
Daniel Gilman ◽  
Simon Birrer ◽  
Anna Nierenberg ◽  
Tommaso Treu ◽  
Xiaolong Du ◽  
...  
Keyword(s):  
Dark Matter ◽  
Mass Fraction ◽  
Mass Concentration ◽  
Cold Dark Matter ◽  
Finite Size ◽  
Mass Function ◽  
Line Of Sight ◽  
Gravitational Lenses ◽  
Likelihood Ratios ◽  
Mass Profile

ABSTRACT The free-streaming length of dark matter depends on fundamental dark matter physics, and determines the abundance and concentration of dark matter haloes on sub-galactic scales. Using the image positions and flux ratios from eight quadruply imaged quasars, we constrain the free-streaming length of dark matter and the amplitude of the subhalo mass function (SHMF). We model both main deflector subhaloes and haloes along the line of sight, and account for warm dark matter free-streaming effects on the mass function and mass–concentration relation. By calibrating the scaling of the SHMF with host halo mass and redshift using a suite of simulated haloes, we infer a global normalization for the SHMF. We account for finite-size background sources, and marginalize over the mass profile of the main deflector. Parametrizing dark matter free-streaming through the half-mode mass mhm, we constrain the thermal relic particle mass mDM corresponding to mhm. At $95 \, {\rm per\, cent}$ CI: mhm < 107.8 M⊙ ($m_{\rm {DM}} \gt 5.2 \ \rm {keV}$). We disfavour $m_{\rm {DM}} = 4.0 \,\rm {keV}$ and $m_{\rm {DM}} = 3.0 \,\rm {keV}$ with likelihood ratios of 7:1 and 30:1, respectively, relative to the peak of the posterior distribution. Assuming cold dark matter, we constrain the projected mass in substructure between 106 and 109 M⊙ near lensed images. At $68 \, {\rm per\, cent}$ CI, we infer $2.0{-}6.1 \times 10^{7}\, {{\rm M}_{\odot }}\,\rm {kpc^{-2}}$, corresponding to mean projected mass fraction $\bar{f}_{\rm {sub}} = 0.035_{-0.017}^{+0.021}$. At $95 \, {\rm per\, cent}$ CI, we obtain a lower bound on the projected mass of $0.6 \times 10^{7} \,{{\rm M}_{\odot }}\,\rm {kpc^{-2}}$, corresponding to $\bar{f}_{\rm {sub}} \gt 0.005$. These results agree with the predictions of cold dark matter.

scholarly journals Constraints on the mass–concentration relation of cold dark matter haloes with 11 strong gravitational lenses

2019 ◽  
Vol 492 (1) ◽  
pp. L12-L16 ◽  
Author(s):  
Daniel Gilman ◽  
Xiaolong Du ◽  
Andrew Benson ◽  
Simon Birrer ◽  
Anna Nierenberg ◽  
...  
Keyword(s):  
Dark Matter ◽  
Mass Concentration ◽  
Cold Dark Matter ◽  
Finite Size ◽  
Mass Range ◽  
Nuisance Parameters ◽  
Gravitational Lenses ◽  
Matter Power Spectrum ◽  
Theoretical Predictions ◽  
History Of

ABSTRACT The mass–concentration relation of dark matter haloes reflects the assembly history of objects in hierarchical structure formation scenarios and depends on fundamental quantities in cosmology such as the slope of the primordial matter power spectrum. This relation is unconstrained by observations on sub-galactic scales. We derive the first measurement of the mass–concentration relation using the image positions and flux ratios from 11 quadruple-image strong gravitational lenses (quads) in the mass range $10^{6}\!-\!10^{10} {\, \mathrm{M}_{\odot }}$, assuming cold dark matter. We model both subhaloes and line-of-sight haloes, finite-size background sources, and marginalize over nuisance parameters describing the lens macromodel. We also marginalize over the logarithmic slope and redshift evolution of the mass–concentration relation, using flat priors that encompass the range of theoretical uncertainty in the literature. At z = 0, we constrain the concentration of $10^{8} \, \mathrm{M}_{\odot }$ haloes $c=12_{-5}^{+6}$ at $68 {{\ \rm per\ cent}}$ CI, and $c=12_{-9}^{+15}$ at $95 {{\ \rm per\ cent}}$ CI. For a $10^{7} {\, \mathrm{M}_{\odot }}$ halo, we obtain $68 {{\ \rm per\ cent}}$ ($95 {{\ \rm per\ cent}}$) constraints $c=15_{-8}^{+9}$ ($c=15_{-11}^{+18}$), while for $10^{9} \, \mathrm{M}_{\odot }$ haloes $c=10_{-4}^{+7}$ ($c=10_{-7}^{+14}$). These results are consistent with the theoretical predictions from mass–concentration relations in the literature and establish strong lensing by galaxies as a powerful probe of halo concentrations on sub-galactic scales across cosmological distance.

scholarly journals Probing dark matter structure down to 107 solar masses: flux ratio statistics in gravitational lenses with line-of-sight haloes

2019 ◽  
Vol 487 (4) ◽  
pp. 5721-5738 ◽  
Author(s):  
Daniel Gilman ◽  
Simon Birrer ◽  
Tommaso Treu ◽  
Anna Nierenberg ◽  
Andrew Benson
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
High Redshift ◽  
Flux Ratio ◽  
Mass Function ◽  
Line Of Sight ◽  
Gravitational Lenses ◽  
Modelling Framework ◽  
Powerful Means ◽  
Mass Functions

Abstract Strong lensing provides a powerful means of investigating the nature of dark matter as it probes dark matter structure on sub-galactic scales. We present an extension of a forward modelling framework that uses flux ratios from quadruply imaged quasars (quads) to measure the shape and amplitude of the halo mass function, including line-of-sight (LOS) haloes and main deflector subhaloes. We apply this machinery to 50 mock lenses – roughly the number of known quads – with warm dark matter (WDM) mass functions exhibiting free-streaming cut-offs parametrized by the half-mode mass mhm. Assuming cold dark matter (CDM), we forecast bounds on mhm and the corresponding thermal relic particle masses over a range of tidal destruction severity, assuming a particular WDM mass function and mass–concentration relation. With significant tidal destruction, at 2σ we constrain $m_{\rm {hm}}\lt 10^{7.9} \left(10^{8.4}\right) \, \mathrm{M}_{\odot }$, or a 4.4 (3.1) keV thermal relic, with image flux uncertainties from measurements and lens modelling of $2{{\ \rm per\ cent}} \left(6{{\ \rm per\ cent}}\right)$. With less severe tidal destruction we constrain $m_{\rm {hm}}\lt 10^{7} \left(10^{7.4}\right) \, \mathrm{M}_{\odot }$, or an 8.2 (6.2) keV thermal relic. If dark matter is warm, with $m_{\rm {hm}} = 10^{7.7} \, \mathrm{M}_{\odot }$ (5.1 keV), we would favour WDM with $m_{\rm {hm}} \gt 10^{7.7} \, \mathrm{M}_{\odot }$ over CDM with relative likelihoods of 22:1 and 8:1 with flux uncertainties of $2{{\ \rm per\ cent}}$ and $6{{\ \rm per\ cent}}$, respectively. These bounds improve over those obtained by modelling only main deflector subhaloes because LOS objects produce additional flux perturbations, especially for high-redshift systems. These results indicate that ∼50 quads can conclusively differentiate between WDM and CDM.

scholarly journals Low-mass halo perturbations in strong gravitational lenses at redshift z ∼ 0.5 are consistent with CDM

2019 ◽  
Vol 485 (2) ◽  
pp. 2179-2193 ◽  
Author(s):  
E Ritondale ◽  
S Vegetti ◽  
G Despali ◽  
M W Auger ◽  
L V E Koopmans ◽  
...  
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Detection Threshold ◽  
Current Data ◽  
Gravitational Lens ◽  
Detection Sensitivity ◽  
Line Of Sight ◽  
Gravitational Lenses ◽  
Lepton Asymmetry ◽  
Low Mass

ABSTRACT We use a sample of 17 strong gravitational lens systems from the BELLS GALLERY survey to quantify the amount of low-mass dark matter haloes within the lensing galaxies and along their lines of sight, and to constrain the properties of dark matter. Based on a detection criterion of 10σ, we report no significant detection in any of the lenses. Using the sensitivity function at the 10σ level, we have calculated the predicted number of detectable cold dark matter (CDM) line-of-sight haloes to be μl = 1.17 ± 1.08, in agreement with our null detection. Assuming a detection sensitivity that improved to the level implied by a 5σ threshold, the expected number of detectable line-of-sight haloes rises to μl = 9.0 ± 3.0. Whilst the current data find zero detections at this sensitivity level (which has a probability of P$^{{\rm 5}\sigma }_{{\rm CDM}}(n_{\rm det}=0)$ = 0.0001 and would be in strong tension with the CDM framework), we find that such a low-detection threshold leads to many spurious detections and non-detections and therefore the current lack of detections is unreliable and requires data with improved sensitivity. Combining this sample with a subsample of 11 SLACS lenses, we constrain the half-mode mass to be log (Mhm) < 12.26 at the 2σ level. The latter is consistent with resonantly produced sterile neutrino masses ms < 0.8 keV at any value of the lepton asymmetry at the 2σ level.

scholarly journals Inference of the cold dark matter substructure mass function at z = 0.2 using strong gravitational lenses

2014 ◽  
Vol 442 (3) ◽  
pp. 2017-2035 ◽  
Author(s):  
S. Vegetti ◽  
L. V. E. Koopmans ◽  
M. W. Auger ◽  
T. Treu ◽  
A. S. Bolton
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Mass Function ◽  
Gravitational Lenses

scholarly journals Halo concentration strengthens dark matter constraints in galaxy-galaxy strong lensing analyses

2021 ◽  
Author(s):  
Nicola C Amorisco ◽  
James Nightingale ◽  
Qiuhan He ◽  
Aristeidis Amvrosiadis ◽  
Xiaoyue Cao ◽  
...  
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Large Population ◽  
Dark Matter Particle ◽  
Mass Function ◽  
Gravitational Lenses ◽  
High Concentration ◽  
Expected Number ◽  
Order Of Magnitude ◽  
Low Mass

Abstract A defining prediction of the cold dark matter (CDM) cosmological model is the existence of a very large population of low-mass haloes. This population is absent in models in which the dark matter particle is warm (WDM). These alternatives can, in principle, be distinguished observationally because halos along the line-of-sight can perturb galaxy-galaxy strong gravitational lenses. Furthermore, the WDM particle mass could be deduced because the cut-off in their halo mass function depends on the mass of the particle. We systematically explore the detectability of low-mass haloes in WDM models by simulating and fitting mock lensed images. Contrary to previous studies, we find that halos are harder to detect when they are either behind or in front of the lens. Furthermore, we find that the perturbing effect of haloes increases with their concentration: detectable haloes are systematically high-concentration haloes, and accounting for the scatter in the mass-concentration relation boosts the expected number of detections by as much as an order of magnitude. Haloes have lower concentration for lower particle masses and this further suppresses the number of detectable haloes beyond the reduction arising from the lower halo abundances alone. Taking these effects into account can make lensing constraints on the value of the mass function cut-off at least an order of magnitude more stringent than previously appreciated.

scholarly journals Evidence of a population of dark subhaloes from Gaia and Pan-STARRS observations of the GD-1 stream

2021 ◽  
Vol 502 (2) ◽  
pp. 2364-2380
Author(s):  
Nilanjan Banik ◽  
Jo Bovy ◽  
Gianfranco Bertone ◽  
Denis Erkal ◽  
T J L de Boer
Keyword(s):  
Dark Matter ◽  
Mass Fraction ◽  
Molecular Clouds ◽  
Globular Clusters ◽  
Cold Dark Matter ◽  
Joint Analysis ◽  
Giant Molecular Clouds ◽  
Total Abundance ◽  
Hydrodynamical Simulation ◽  
Stellar Density

ABSTRACT New data from the Gaia satellite, when combined with accurate photometry from the Pan-STARRS survey, allow us to accurately estimate the properties of the GD-1 stream. Here, we analyse the stellar density variations in the GD-1 stream and show that they cannot be due to known baryonic structures such as giant molecular clouds, globular clusters, or the Milky Way’s bar or spiral arms. A joint analysis of the GD-1 and Pal 5 streams instead requires a population of dark substructures with masses ≈107–$10^9 \ \rm {M}_{\odot }$. We infer a total abundance of dark subhaloes normalized to standard cold dark matter $n_{\rm sub}/n_{\rm sub, CDM} = 0.4 ^{+0.3}_{-0.2}$ (68 per cent), which corresponds to a mass fraction contained in the subhaloes $f_{\rm {sub}} = 0.14 ^{+0.11}_{-0.07} {{\ \rm per\ cent}}$, compatible with the predictions of hydrodynamical simulation of cold dark matter with baryons.

scholarly journals Out of sight, out of mind? The impact of correlated clustering in substructure lensing

2021 ◽  
Author(s):  
Alexandres Lazar ◽  
James S Bullock ◽  
Michael Boylan-Kolchin ◽  
Robert Feldmann ◽  
Onur Çatmabacak ◽  
...  
Keyword(s):  
Dark Matter ◽  
Principal Axis ◽  
Major Axis ◽  
Line Of Sight ◽  
Gravitational Lenses ◽  
Local Clustering ◽  
Analytic Expression ◽  
Halo Masses ◽  
The Impact

Abstract A promising route for revealing the existence of dark matter structures on mass scales smaller than the faintest galaxies is through their effect on strong gravitational lenses. We examine the role of local, lens-proximate clustering in boosting the lensing probability relative to contributions from substructure and unclustered line-of-sight (LOS) haloes. Using two cosmological simulations that can resolve halo masses of Mhalo ≃ 109 M⊙ (in a simulation box of length Lbox ∼ 100 Mpc) and 107 M⊙ (Lbox ∼ 20 Mpc), we demonstrate that clustering in the vicinity of the lens host produces a clear enhancement relative to an assumption of unclustered haloes that persists to >20 Rvir. This enhancement exceeds estimates that use a two-halo term to account for clustering, particularly within 2 − 5 Rvir. We provide an analytic expression for this excess, clustered contribution. We find that local clustering boosts the expected count of 109 M⊙ perturbing haloes by ${\sim }35{{\ \rm per\ cent}}$ compared to substructure alone, a result that will significantly enhance expected signals for low-redshift (zl ≃ 0.2) lenses, where substructure contributes substantially compared to LOS haloes. We also find that the orientation of the lens with respect to the line of sight (e.g. whether the line of sight passes through the major axis of the lens) can also have a significant effect on the lensing signal, boosting counts by an additional $\sim 50{{\ \rm per\ cent}}$ compared to a random orientations. This could be important if discovered lenses are biased to be oriented along their principal axis.

scholarly journals Probing non-spherical dark halos in the Galactic dwarf satellites

2013 ◽  
Vol 9 (S298) ◽  
pp. 411-411
Author(s):  
Kohei Hayashi ◽  
Masashi Chiba
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Milky Way ◽  
Velocity Dispersion ◽  
Line Of Sight ◽  
Spherical Structure ◽  
Spherical Models ◽  
Galactic Satellites ◽  
Best Fitting

AbstractWe construct axisymmetric mass models for dwarf spheroidal (dSph) galaxies in the Milky Way to obtain realistic limits on the non-spherical structure of their dark halos. This is motivated by the fact that the observed luminous parts of the dSphs are actually non-spherical and cold dark matter models predict non-spherical virialized dark halos on sub-galactic scales. Applying these models to line-of-sight velocity dispersion profiles along three position angles in six Galactic satellites, we find that the best fitting cases for most of the dSphs yield not spherical but oblate and flattened dark halos. We also find that the mass of the dSphs enclosed within inner 300 pc varies depending on their total luminosities, contrary to the conclusion of previous spherical models. This suggests the importance of considering non-spherical shapes of dark halos in dSph mass models.

The Expected Mass Function for Low‐Mass Galaxies in a Cold Dark Matter Cosmology: Is There a Problem?

2001 ◽  
Vol 563 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Weihsueh A. Chiu ◽  
Nickolay Y. Gnedin ◽  
Jeremiah P. Ostriker
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Mass Function ◽  
Low Mass

scholarly journals Predictably missing satellites: subhalo abundances in Milky Way-like haloes

2019 ◽  
Vol 486 (4) ◽  
pp. 4545-4568 ◽  
Author(s):  
Catherine E Fielder ◽  
Yao-Yuan Mao ◽  
Jeffrey A Newman ◽  
Andrew R Zentner ◽  
Timothy C Licquia
Keyword(s):  
Dark Matter ◽  
Confidence Level ◽  
Mass Concentration ◽  
Cold Dark Matter ◽  
Milky Way ◽  
Scale Factor ◽  
Magellanic Clouds ◽  
Small Scales ◽  
Major Merger ◽  
The Impact

ABSTRACT On small scales there have been a number of claims of discrepancies between the standard cold dark matter (CDM) model and observations. The ‘missing satellites problem’ infamously describes the overabundance of subhaloes from CDM simulations compared to the number of satellites observed in the Milky Way. A variety of solutions to this discrepancy have been proposed; however, the impact of the specific properties of the Milky Way halo relative to the typical halo of its mass has yet to be explored. Motivated by recent studies that identified ways in which the Milky Way is atypical, we investigate how the properties of dark matter haloes with mass comparable to our Galaxy’s – including concentration, spin, shape, and scale factor of the last major merger – correlate with the subhalo abundance. Using zoom-in simulations of Milky Way-like haloes, we build two models of subhalo abundance as functions of host halo properties. From these models we conclude that the Milky Way most likely has fewer subhaloes than the average halo of the same mass. We expect up to 30 per cent fewer subhaloes with low maximum rotation velocities ($V_{\rm max}^{\rm sat} \sim 10$ km s−1) at the 68 per cent confidence level and up to 52 per cent fewer than average subhaloes with high rotation velocities ($V_{\rm max}^{\rm sat} \gtrsim 30$ km s−1, comparable to the Magellanic Clouds) than would be expected for a typical halo of the Milky Way’s mass. Concentration is the most informative single parameter for predicting subhalo abundance. Our results imply that models tuned to explain the missing satellites problem assuming typical subhalo abundances for our Galaxy may be overcorrecting.

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