Constraints on the Self-Interaction Cross Section of Dark Matter from Numerical Simulations of the Merging Galaxy Cluster 1E 0657–56

By S. Randall, M. Markevitch, D. Clowe, Anthony H. Gonzalez, M. Bradač. 2007

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We compare recent results from X-ray, strong lensing, weak lensing, and optical observations with numerical simulations of the merging galaxy cluster 1E 0657–56. X-ray observations reveal a bullet-like subcluster with a prominent bow shock, which gives an estimate for the merger velocity of 4700 km s−1, while lensing results show that the positions of the total mass peaks are consistent with the centroids of the collisionless galaxies (and inconsistent with the X-ray brightness peaks). Previous studies, based on older observational data sets, have placed upper limits on the self-interaction cross section of dark matter per unit mass, σ/m, using simplified analytic techniques. In this work, we take advantage of new, higher quality observational data sets by running full N-body simulations of 1E 0657–56 that include the effects of self-interacting dark matter, and comparing the results with observations. Furthermore, the recent data allow for a new independent method of constraining σ/m, based on the nonobservation of an offset between the bullet subcluster mass peak and galaxy centroid. This new method places an upper limit (68% confidence) of σ/m < 1.25 cm2 g−1. If we make the assumption that the subcluster and the main cluster had equal mass-to-light ratios prior to the merger, we derive our most stringent constraint of σ/m < 0.7 cm2 g−1, which comes from the consistency of the subcluster’s observed mass-to-light ratio with the main cluster’s, and with the universal cluster value, ruling out the possibility of a large fraction of dark matter particles being scattered away due to collisions. Our limit is a slight improvement over the previous result from analytic estimates, and rules out most of the 0.5-5 cm2 g−1 range invoked to explain inconsistencies between the standard collisionless cold dark matter model and observations.

Subfields: Astronomy and Astrophysics, Global and Planetary Change, Instrumentation

View Paper: https://www.semanticscholar.org/paper/1fac2c00b068ff8a0e58e1c072d200f7931ea618

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Citations in the corpus

What does the Bullet Cluster tell us about Self-Interacting Dark Matter? (2016, methodology): “…the galaxies and DM associated with the smaller DM halo (the ‘bullet’) as well as limits on the loss of DM mass from the bullet have been used to place constraints on the DM–DM elastic scattering cross-section (Randall et al. 2008; Kahlhoefer et al. 2014, hereafter R08 and K14, respectively).”
THE DENSITY PROFILES OF MASSIVE, RELAXED GALAXY CLUSTERS. II. SEPARATING LUMINOUS AND DARK MATTER IN CLUSTER CORES (2012, background): “Rocha et al. (2012) and Peter et al. (2012) showed that a cross-section σ ∼ 0.1 cm2 g−1 can produce ≈ 20 kpc cores in clusters without violating any current constraints, e.g., from the asphericity of cluster cores or the Bullet Cluster (Randall et al. 2008).”
ScannerS: constraining the phase diagram of a complex scalar singlet at the LHC (2013, result): “In the first model, which we called model 0, one of the phases leads to a massless dark matter candidate which is already excluded by the Bullet Cluster results.”
Galaxy formation theory (2010, background): “…we cannot fully rule out that dark matter is warm or self-interacting, although good constraints exist on both of these properties (Markevitch eal., 2004; Boehm and Schaeff r, 2005; Ahn and Shapiro, 2005; Miranda and Macciò, 2007; Randall et al., 2008; Yükselet al., 2008; Boyarsky et al., 2008).”
Cosmological Parameters from Observations of Galaxy Clusters (2011, methodology): “Randall et al. (2008) additionally use the non-detection of an offset between the lensing peaks and the galaxy centroids for the Bullet Cluster to refine this constraint to σ/m < 1.5 cm2 g−1.”
The behaviour of dark matter associated with four bright cluster galaxies in the 10 kpc core of Abell 3827 (2015, background): “Measurements of this lag yielded an upper limit on dark matter’s self-interaction cross-section σ/m < 1.2 cm2 g−1 if the particle momentum exchange is isotropic, or σ/m < 0.7 cm2 g−1 if it is directional (Randall et al. 2008; Kahlhoefer et al. 2014).”
Cosmological simulations with self-interacting dark matter – II. Halo shapes versus observations (2012, background): “This constraint is one to two orders of magnitude tighter than other typical constraints on velocityindependent scattering (Yoshida et al. 2000b; Gnedin & Ostriker 2001; Randall et al. 2008).”
Colliding clusters and dark matter self-interactions (2013, methodology): “Indeed, the observed separation depends on the central density of the main cluster (see Randall et al. 2008).”
Core formation in dwarf haloes with self-interacting dark matter: no fine-tuning necessary (2014, background): “1 cm2 g−1) come from galaxy clusters with characteristic rms velocities vrms ' 1000 km s−1 (Yoshida et al., 2000; Gnedin & Ostriker, 2001; Randall et al., 2008; Rocha et al., 2013; Peter et al., 2013).”
Creation of cosmic structure in the complex galaxy cluster merger Abell 2744 (2011, methodology): “Indeed, even tighter constraints (σ/m < 0.7 cm2 g−1) were obtained from the Bullet Cluster by (Randall et al. 2008), who interpreted the offsets between all three cluster components via tailored hydrodynamical simulations.”