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

By S. Vegetti, Leon V. E. Koopmans, M. Auger, T. Treu, A. Bolton. 2014

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We present the results of a search for galaxy substructures in a sample of 11 gravitational lens galaxies from the Sloan Lens ACS Survey by Bolton et al. We find no significant detection of mass clumps, except for a luminous satellite in the system SDSS J0956+5110. We use these non-detections, in combination with a previous detection in the system SDSS J0946+1006, to derive constraints on the substructure mass function in massive early-type host galaxies with an average redshift ˜ 0.2 and an average velocity dispersion ˜ 270 km s-1. We perform a Bayesian inference on the substructure mass function, within a median region of about 32 kpc2 around the Einstein radius ( ˜ 4.2 kpc). We infer a mean projected substructure mass fraction f = 0.0076_{-0.0052}^{+0.0208} at the 68 per cent confidence level and a substructure mass function slope α <2.93 at the 95 per cent confidence level for a uniform prior probability density on α. For a Gaussian prior based on cold dark matter (CDM) simulations, we infer f = 0.0064^{+0.0080}_{-0.0042} and a slope of α = 1.90^{+0.098}_{-0.098} at the 68 per cent confidence level. Since only one substructure was detected in the full sample, we have little information on the mass function slope, which is therefore poorly constrained (i.e. the Bayes factor shows no positive preference for any of the two models). The inferred fraction is consistent with the expectations from CDM simulations and with inference from flux ratio anomalies at the 68 per cent confidence level.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/f79e9deae23ee535e1c8af52fd2ea629c1b9e9da

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Citations in the corpus

TDCOSMO. I. An exploration of systematic uncertainties in the inference of $H_0$ from time-delay cosmography (2019, background): “Aside from specific features arising from well-identified substructures in any given lens, no statistically significant correction to simple parametric lens models is found by Vegetti et al. (2014).”
Disruption of Dark Matter Substructure: Fact or Fiction? (2017, methodology): “…either by using timedelays (e.g., Keeton & Moustakas 2009), flux-ratio anomalies (e.g., Metcalf & Madau 2001; Bradač et al. 2002; Dalal & Kochanek 2002), or perturbations of the surface brightness distribution of lensed arcs and Einstein rings (e.g. Vegetti & Koopmans 2009; Vegetti et al. 2014).”
Gravitational probes of dark matter physics (2017, background): “ of \gravitational imaging" [609, 309] has gained traction, mapping out perturbations in a few dozen Einstein ring galaxies, which are also consistent with CDM but again with large uncertainties [610, 611, 612]. Why so few targets, and what is the path to stronger tests of dark matter microphys”
THE POPULATION OF GALAXY–GALAXY STRONG LENSES IN FORTHCOMING OPTICAL IMAGING SURVEYS (2015, methodology): “…has been used to constrain the masses and density profiles of galaxies (Auger et al. 2010; Barnabè et al. 2011), the dark sub-halo population (Vegetti et al. 2014), cosmological parameters (Collett & Auger 2014; Oguri et al. 2012; Suyu et al. 2014), the high redshift luminosity function…”
Time delay cosmography (2016, background): “…to use lensed quasars to learn about the astrophysics of dark matter (Metcalf and Madau 2001; Dalal and Kochanek 2002; Metcalf 2005; Xu et al. 2009; Vegetti et al. 2014; Nierenberg et al. 2014), active galactic nuclei (Poindexter et al. 2008; Eigenbrod et al. 2008a, b; Blackburne et al. 2010;…”
DETECTION OF LENSING SUBSTRUCTURE USING ALMA OBSERVATIONS OF THE DUSTY GALAXY SDP.81 (2016, methodology): “…7 data detects a M = 108.96±0.12M subhalo with a significance of 6.9σ and produces substructure bounds that are consistent with previous lensing measurements of other systems (Dalal & Kochanek 2002; Vegetti et al. 2014), and also consistent with theoretical expectations as described in Section 6.”