Probing Dark Matter Substructure in Lens Galaxies

By M. Chiba. 2001

176 citations recorded by the source corpus.

We investigate the effects of numerous dark matter subhalos in a galaxy-sized halo on the events of strong lensing to assess their presence as expected from the cold dark matter scenario. Lens galaxies are represented by a smooth ellipsoid in an external shear field and additional cold dark matter subhalos taken from Monte Carlo realizations that accord with recent N-body results. We also consider other possible perturbers, globular clusters and luminous dwarf satellites, for comparison. We then apply the models to the particular lens systems with four images, B1422+231 and PG 1115+080, for which smooth lens models are unable to simultaneously reproduce both the positions of the images and their radio flux ratios or dust-free optical flux ratios. We show that the perturbations by both globular clusters and dwarf satellites are too small to change the flux ratios, whereas cold dark matter subhalos are the most likely perturbers to reproduce the observed flux ratios in a statistically significant manner. This result suggests to us the presence of numerous subhalos in lens galaxies, which is consistent with the results of cosmological N-body simulations.

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Citations in the corpus

ΛCDM-based Models for the Milky Way and M31. I. Dynamical Models (2001, background): “…known radio/optical lenses show significant variance of image flux ratios from that of smooth lens models, which has been suggested by several groups to be evidence for dark/faint clumps in the line of sight (Chiba 2002; Metcalf & Zhao 2002; Dalal & Kochanek 2002; Keeton 2002; Bradač et al. 2002).”
Direct Detection of Cold Dark Matter Substructure (2001, background): “Recently, Metcalf & Madau (2001) quantified the effects of CDM satellites using simulations and found that the effects should be readily detected, and Chiba (2002) demonstrated that plausible CDM satellite distributions could explain the anomalous flux ratios in B1422+231 and PG1115+080.”
Dark Matter Substructure and Gamma-Ray Annihilation in the Milky Way Halo (2006, background): “…counterparts, the substructure populationmay be detectable via flux ratio anomalies in strong gravitational lenses (e.g., Metcalf & Madau 2001; Chiba 2002), through its effects on stellar streams (e.g., Ibata et al. 2002; Mayer et al. 2002), or possibly via -rays from dark matter annihilation…”
Orbital parameters of infalling dark matter substructures (2004, result): “Observational tests for its presence, though not yet conclusive, are in good agreement with the theoretical expectations (Metcalf & Madau 2001; Chiba 2002; Dalal & Kochanek 2002).”
Bayesian strong gravitational-lens modelling on adaptive grids: objective detection of mass substructure in Galaxies (2008, background): “…can be related to the presence of (dark matter) substructure around the lensing galaxy on scales smaller than the image separation (Bradačet al. 2002; Chiba 2002; Dalal & Kochanek 2002; Metcalf & Zhao 2002; Keeton et al. 2003; Kochanek & Dalal 2004; Bradač et al. 2004; Keeton et al. 2005).”
Inference of the cold dark matter substructure mass function at z = 0.2 using strong gravitational lenses (2014, background): “Indeed, Metcalf & Madau (2001), Chiba (2002), Dalal & Kochanek (2002), Metcalf & Zhao (2002), Keeton et al. (2003) and Nierenberg et al. (2014) showed that mass substructure could be responsible for a violation of the magnification relations.”
A Determination of H0 with the CLASS Gravitational Lens B1608+656. III. A Significant Improvement in the Precision of the Time Delay Measurements (2002, background): “Recently, several papers have suggested that the substructure is due to the small dark matter satellite halos expected from CDM structure-formation models (e.g., Metcalf & Madau 2001; Chiba 2002; Dalal &Kochanek 2002).”
Detection of a dark substructure through gravitational imaging (2009, unknown): “2002; Chiba 2002; Dalal & Kochanek 2002; Metcalf & Zhao 2002; Keeton et al. 2003; Kochanek & Dalal 2004; Bradač et al. 2004; Keeton et al. 2005; McKean et al. 2007; Chen et al. 2007; More et al. 2009).”
Quasar Microlensing at High Magnification and the Role of Dark Matter: Enhanced Fluctuations and Suppressed Saddle Points (2002, background): “…andMini-Halos The present work is fundamentally similar to (although on the surface quite different from) that of Metcalf & Madau (2001), Chiba (2002), and Dalal & Kochanek (2002) who argue that the brightness ratio anomalies observed in quadruple systems are due to the presence of dark…”
Gravitational lensing (2010, background): “In [78] it was discussed that the sub-halo population of CDM halos produces perturbations of the magnitude required for explaining anomalous flux ratios.”
CLUMPY STREAMS FROM CLUMPY HALOS: DETECTING MISSING SATELLITES WITH COLD STELLAR STRUCTURES (2010, unknown): “Gravitational lensing has been suggested to be a useful tool to probe the presence of subhalos (Chiba 2002; Metcalf & Zhao 2002; Chen et al. 2003; Moustakas & Metcalf 2003; Metcalf et al. 2004; Keeton & Moustakas 2009; Riehm et al. 2009; Xu et al. 2009).”
Substructures in cold dark matter haloes (2003, background): “Direct evidence for the large population of dark satellites predicted by CDM models comes from the anomalous flux ratios of multiply imaged quasars (Mao & Schneider 1998; Chiba 2002; Dalal & Kochanek 2002).”