Data di Pubblicazione:
2007
Citazione:
A wide-angle tail radio galaxy in the COSMOS field: Evidence for cluster formation / V. Smolčić, E. Schinnerer, A. Finoguenov, I. Sakelliou, C.L. Carilli, C.S. Botzler, M. Brusa, N. Scoville, M. Ajiki, P. Capak, L. Guzzo, G. Hasinger, C. Impey, K. Jahnke, J.S. Kartaltepe, H.J. Mccracken, B. Mobasher, T. Murayama, S.S. Sasaki, Y. Shioya, Y. Taniguchi, J.R. Trump. - In: ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES. - ISSN 0067-0049. - 172:1(2007), pp. 295-313. [10.1086/516583]
Abstract:
We have identified a complex galaxy cluster system in the COSMOS field via a wide-angle tail (WAT) radio galaxy, consistent with the idea that WAT galaxies can be used as tracers of clusters. The WAT galaxy, CWAT-01, is coincident with an elliptical galaxy resolved in the HSTACS image. Using the COSMOS multiwavelength data set, we derive the radio properties of CWAT-01 and use the optical and X-ray data to investigate its host environment. The cluster hosting CWAT-01 is part of a larger assembly consisting of a minimum of four X-ray luminous clusters within â¼2 Mpc distance. We apply hydrodynamic models that combine ram pressure and buoyancy forces on CWAT-01. These models explain the shape of the radio jets only if the galaxy's velocity relative to the intracluster medium (ICM) is in the range of about 300-550 km s-1, which is higher than expected for brightest cluster galaxies (BCGs) in relaxed systems. This indicates that the CWAT-01 host cluster is not relaxed but is possibly dynamically young. We argue that such a velocity could have been induced through subcluster merger within the CWAT-01 parent cluster and/or cluster-cluster interactions. Our results strongly indicate that we are witnessing the formation of a large cluster from an assembly of multiple clusters, consistent with the hierarchical scenario of structure formation. We estimate the total mass of the final cluster to be approximately 20% of the mass of the Coma Cluster.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
cosmology : observations; galaxies : individual (CWAT-01); galaxies : jets radio; continuum : galaxies; surveys; X-rays : galaxies : clusters
Elenco autori:
V. Smolčić, E. Schinnerer, A. Finoguenov, I. Sakelliou, C.L. Carilli, C.S. Botzler, M. Brusa, N. Scoville, M. Ajiki, P. Capak, L. Guzzo, G. Hasinger, C. Impey, K. Jahnke, J.S. Kartaltepe, H.J. Mccracken, B. Mobasher, T. Murayama, S.S. Sasaki, Y. Shioya, Y. Taniguchi, J.R. Trump
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