The ALPINE-ALMA [CII] survey: A triple merger at z ∼ 4.56

G. C. Jones, M. Béthermin, Y. Fudamoto, M. Ginolfi, P. Capak, P. Cassata, A. Faisst, O. Le Fèvre, D. Schaerer, J. Silverman, L. Yan, S. Bardelli, M. Boquien, A. Cimatti, M. Dessauges-Zavadsky, M. Giavalisco, C. Gruppioni, E. Ibar, Y. Khusanova, A. M. KoekemoerB. C. Lemaux, F. Loiacono, R. Maiolino, P. A. Oesch, F. Pozzi, D. Riechers, G. Rodighiero, M. Talia, L. Vallini, D. Vergani, G. Zamorani, E. Zucca

Research output: Contribution to journalArticlepeer-review

Abstract

We report the detection of [CII]λ158µm emission from a system of three closely-separated sources in the COSMOS field at z ∼ 4.56, as part of the ALMA Large Program to INvestigate CII at Early times (ALPINE). The two dominant sources are closely associated, both spatially (1.600 ∼ 11 kpc) and in velocity (∼ 100 km s−1), while the third source is slightly more distant (2.800 ∼ 18kpc, ∼ 300 km s−1). The second strongest source features a slight velocity gradient, while no significant velocity gradient is seen in the other two sources. Using the observed [C II] luminosities, we derive a total log10(SFR[CII] [M year−1]) = 2.8 ± 0.2, which may be split into contributions of 59%, 31%, and 10% from the central, east, and west sources, respectively. Comparison of these [C II] detections to recent zoom-in cosmological simulations suggests an ongoing major merger. We are thus witnessing a system in a major phase of mass build-up by merging, including an on-going major merger and an upcoming minor merger, which is expected to end up in a single massive galaxy by z ∼ 2.5.

Original languageEnglish
JournalUnknown Journal
Publication statusPublished - 2019 Aug 21
Externally publishedYes

Keywords

  • Galaxies: evolution –
  • Galaxies: high-redshift
  • Galaxies: interaction –

ASJC Scopus subject areas

  • General

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