Revealing the Properties of Dark Matter in the Merging Cluster MACS J0025.4−1222
Open accessAbstract
We constrain the physical nature of dark matter using the newly identified massive merging galaxy cluster MACS J0025.4–1222. As was previously shown by the example of the Bullet Cluster (1E 0657–56), such systems are ideal laboratories for detecting isolated dark matter and distinguishing between cold dark matter (CDM) and other scenarios (e.g., self-interacting dark matter, alternative gravity theories). MACS J0025.4–1222 consists of two merging subclusters of similar richness at z = 0.586. We measure the distribution of X-ray-emitting gas from Chandra X-ray data and find it to be clearly displaced from the distribution of galaxies. A strong (information from highly distorted arcs) and weak (using weakly distorted background galaxies) gravitational lensing analysis based on Hubble Space Telescope observations and Keck arc spectroscopy confirms that the subclusters have near-equal mass. The total mass distribution in each of the subclusters is clearly offset (at >4 σ significance) from the peak of the hot X-ray-emitting gas (the main baryonic component) but aligned with the distribution of galaxies. We measure the fractions of mass in hot gas (0.09 + 0.07 −0.03 ) and stars (0.010 + 0.007 −0.004 ), consistent with those of typical clusters, finding that dark matter is the dominant contributor to the gravitational field. Under the assumption that the subclusters experienced a head-on collision in the plane of the sky, we obtain an order-of-magnitude estimate of the dark matter self-interaction cross section of σ/m < 4 cm 2 g −1 , reaffirming the results from the Bullet Cluster on the collisionless nature of dark matter.
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According to Bradač et al. (2008), the galaxy-mass offset for ZwCl 1358 east is -4 +/- 4 (-29 kpc); with the mean Harvey et al. gas mass correction, the final delta_SI is -33 kpc, a substantial change from the H15 value of -151 kpc.
“According to Table 2 of Bradač et al. (2008), the galaxymass offset is -4 4 (-29 kpc).With the mean H15 correction for gas mass, the final value for δ SI is -33 kpc.This is a substantial change from the H15 value of -151 kpc.”
From The Mismeasure of Mergers: Revised Limits on Self-interacting Dark Matter in Merging Galaxy Clusters (2018) · cites this paper as Bradač et al. (2008)
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Experimental — accuracy not yet measuredFor MACS J0025 west, the Harvey et al. single-band weak-lensing position is still 110 kpc from the geometric center of the outermost Bradač et al. (2008) contours, which are driven by multiband weak lensing.
“However, the outermost Bradač et al. (2008) contours are indeed driven by (multiband) weak lensing, and the H15 (single-band) weak-lensing position is still 110 kpc from their geometric center.”
From The Mismeasure of Mergers: Revised Limits on Self-interacting Dark Matter in Merging Galaxy Clusters (2018) · cites this paper as Bradač et al. (2008)
Figure 4 identifies the contours as a combined weak- and strong-lensing mass reconstruction, but does not say the outermost contours are driven by weak lensing. Section 2 says F814W was the primary weak-lensing band; other bands aided source identification and foreground exclusion, rather than providing multiband shape measurements. The paper does not report the later Harvey et al. position or its 110 kpc separation. (LLM, conf=0.84)
Experimental — accuracy not yet measuredIn general, a strong+weak lensing position potentially disfavors SIDM by missing possible bridge effects, so the paper uses the Bradač et al. (2008) position to build the case that analysis choices favorable to SIDM are not needed.
“In general, strong+weaklensing position potentially disfavors SIDM by missing possible bridge effects, so we use the Bradač et al. (2008) position to build the case that we need not make analysis choices favorable to SIDM to show that the”
From The Mismeasure of Mergers: Revised Limits on Self-interacting Dark Matter in Merging Galaxy Clusters (2018) · cites this paper as Bradač et al. (2008)
A recent strong-lensing analysis by Cibirka et al. (2018) lends further support to the Bradač et al. (2008) results for MACS J0025 west.
“A recent strong-lensing analysis (Cibirka et al. 2018) lends further support to the Bradač et al. (2008) results.”
From The Mismeasure of Mergers: Revised Limits on Self-interacting Dark Matter in Merging Galaxy Clusters (2018) · cites this paper as Bradač et al. (2008)
The impact of the choice of the Bradač et al. (2008) position on the final result is small.
“in Section 4 we assess the impact of this particular choice on the final result; it is small.”
From The Mismeasure of Mergers: Revised Limits on Self-interacting Dark Matter in Merging Galaxy Clusters (2018) · cites this paper as Bradač et al. (2008)
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Cites
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Flagged first, then by citations
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Photon and graviton mass limits
Goldhaber, A. S., & Nieto, M. M. (2010) · Reviews of Modern Physics · doi:10.1103/revmodphys.82.939 · Cited by 445 · see citing works
The Mismeasure of Mergers: Revised Limits on Self-interacting Dark Matter in Merging Galaxy Clusters
Wittman, D., Golovich, N., & Dawson, W. A. (2018) · The Astrophysical Journal · doi:10.3847/1538-4357/aaee77 · Cited by 80 · see citing works
- Authors
- Bradač, M., Allen, S. W., Treu, T., Ebeling, H., Massey, R., Morris, R. G., von der Linden, A., & Applegate, D.
- Affiliations
- University of California, Santa Barbara (US)
- Kavli Institute for Particle Astrophysics and Cosmology (US)
- University of Hawaiʻi at Mānoa (US)
- Royal Observatory (GB)
- ORCID
- Venue
- The Astrophysical Journal
- Publisher
- American Astronomical Society
- Published
- 2008-11-10
- Volume
- 687
- Issue
- 2
- Pages
- 959-967
- ISSN
- 0004-637X (ISSN-L)
- 1538-4357
- OpenAlex
- W2152797029
- Cited by
- 303
- References
- 2
- Citations by year
- 2026: 4 · 2025: 18 · 2024: 10 · 2023: 15 · 2022: 13 · 2021: 12 · 2020: 13 · 2019: 13 · 2018: 14 · 2017: 13 · 2016: 21 · 2015: 24 · 2014: 21 · 2013: 18 · 2012: 25
- FWCI
- 11.07
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Locations
- The Astrophysical Journal (publishedVersion)
- Durham Research Online (Durham University) (publishedVersion, other-oa)
- Durham Research Online (Durham University) (acceptedVersion)
- arXiv (Cornell University) (submittedVersion)
- arXiv (Cornell University)
- Funders
- National Science Foundation (0642621, DE-AC02-76SF00515, CAREER, NAS 5-26555)
- David and Lucile Packard Foundation (DE-AC02-76SF00515)
- U.S. Department of Energy (11100, 76SF00515, DE–AC02–76SF00515, AC02‐76SF00515, No. DE-AC02–76SF00515, NAS 5-26555, DE-AC02-)
- National Aeronautics and Space Administration (NAS 526555, NNX08AD79G, 526555)
- Alfred P. Sloan Foundation (11100)
- W. M. Keck Foundation
- California Institute of Technology
- Space Telescope Science Institute (NAS5- 26555, 5-26555, 26555)
- Science and Technology Facilities Council (PP/E006450/1, DE-AC02-76SF00515)
- Topics
- Physical Sciences › Physics and Astronomy › Nuclear and High Energy Physics › Dark Matter and Cosmic Phenomena
- Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Galaxies: Formation, Evolution, Phenomena
- Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Cosmology and Gravitation Theories
- Keywords
- dark matter self-interaction, cold dark matter, cluster mergers, Bullet Cluster, gravitational lensing, dark matter cross section, weak gravitational lensing, strong gravitational lensing
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