Astronomy:Abell 3667
| Abell 3667 | |
|---|---|
| Deep optical image containing numerous stars and galaxies in Abell 3667 Deep optical view of Abell 3667 obtained with the Dark Energy Camera | |
| Observation data (Epoch J2000) | |
| Constellation(s) | Pavo |
| Right ascension | 20h 12m 33.68s |
| Declination | −56° 50′ 26.3″ |
| Velocity dispersion | 1,056 ± 38 km/s |
| Redshift | 0.0553 ± 0.0002 |
| Notable features | Prominent X-ray cold front and two radio relics |
| Other designations | |
| ACO 3667 | |
Abell 3667, also designated ACO 3667, is a massive galaxy cluster in the southern constellation Pavo.[1] It has a measured redshift of 0.0553 and is undergoing a merger between smaller galaxy systems. The cluster is known for a prominent X-ray cold front and two large radio relics on opposite sides of its center.[2]
Structure and merger
Spectroscopic observations identified 550 cluster members among 910 galaxies measured across the surrounding field. Their positions and velocities separate into two principal structures, providing evidence that Abell 3667 formed through a major cluster merger. The measured velocity dispersion of its member galaxies is 1,056 ± 38 km/s.[2]
Observations with the Chandra X-ray Observatory revealed a cold front about 0.5 Mpc (1.6 Mly) across near the cluster core. The front marks the boundary of a cool, dense gas cloud moving through hotter gas at approximately 1,400 km/s (870 mi/s), close to the local speed of sound. It is interpreted as the surviving core of a smaller cluster disrupted during the merger.[3] Later X-ray measurements found indications that gas near the center is rotating, supporting an off-center merger rather than a strictly head-on collision.[4]
Radio and optical features
Abell 3667 contains northwestern and southeastern radio relics produced by synchrotron radiation in the outskirts of the cluster. Observations with the MeerKAT radio telescope resolved the relics into networks of narrow filaments associated with particle acceleration and changes in the local magnetic field. The observations also confirmed an elongated radio halo behind the merging subcluster.[5] XMM-Newton observations detected an X-ray shock with a Mach number of about 1.8 at the southeastern relic.[6]
Deep observations made with the Dark Energy Camera revealed a faint bridge of intracluster light extending about 400 kpc (1.3 Mly) between the cluster's two brightest cluster galaxies. Its color and surface brightness are consistent with stars being stripped during a major merger, preserving a visible record of the interaction between the two systems.[7]
See also
- Abell catalogue
- Intracluster medium
- List of Abell clusters
- Radio relic
References
- ↑ 1.0 1.1 "Abell 3667". Centre de données astronomiques de Strasbourg. https://simbad.u-strasbg.fr/simbad/sim-id?Ident=Abell+3667.
- ↑ 2.0 2.1 2.2 Owers, Matt S.; Couch, Warrick J.; Nulsen, Paul E. J. (2009). "Substructure in the Cold Front Cluster Abell 3667". The Astrophysical Journal 693 (1): 901–914. doi:10.1088/0004-637X/693/1/901. Bibcode: 2009ApJ...693..901O.
- ↑ Vikhlinin, Alexey; Markevitch, Maxim; Murray, Stephen S. (2001). "A Moving Cold Front in the Intergalactic Medium of A3667". The Astrophysical Journal 551 (1): 160–171. doi:10.1086/320078. Bibcode: 2001ApJ...551..160V.
- ↑ Omiya, Y. et al. (2024). "Indications of an offset merger in Abell 3667". Astronomy & Astrophysics 689: A173. doi:10.1051/0004-6361/202449992. Bibcode: 2024A&A...689A.173O.
- ↑ de Gasperin, F. et al. (2022). "MeerKAT view of the diffuse radio sources in Abell 3667 and their interactions with the thermal plasma". Astronomy & Astrophysics 659: A146. doi:10.1051/0004-6361/202142658. Bibcode: 2022A&A...659A.146D.
- ↑ Storm, Emma; Vink, Jacco; Zandanel, Fabio; Akamatsu, Hiroki (2018). "XMM–Newton observations of the Southeastern radio relic in Abell 3667". Monthly Notices of the Royal Astronomical Society 479 (1): 553–561. doi:10.1093/mnras/sty1435. Bibcode: 2018MNRAS.479..553S.
- ↑ Englert, Anthony M.; Dell'Antonio, Ian; Montes, Mireia (2025). "The Intracluster Light of Abell 3667: Unveiling an Optical Bridge in LSST Precursor Data". The Astrophysical Journal Letters 989 (1): L2. doi:10.3847/2041-8213/ade8f1. Bibcode: 2025ApJ...989L...2E.
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