The ALPINE-ALMA [C II] 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. D. Silverman, Lin 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 journalReview articlepeer-review

7 Citations (Scopus)

Abstract

We report the detection of [C II] λ158 μm emission from a system of three closely separated sources in the Cosmic Evolution Survey (COSMOS) field at z ∼ 4.56, as part of the Atacama Large Millimeter/submillimeter Array (ALMA) Large Program to INvestigate C II at Early times (ALPINE). The two most luminous sources are closely associated, both spatially (1.6 arcsec ∼ 11 kpc) and in velocity (∼100 km s−1), while the third source is slightly more distant (2.8 arcsec ∼ 18 kpc, ∼300 km s−1). The second most luminous 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[C II] [M☉ yr−1]) = 2.8 ± 0.2, which may be split into contributions of 59, 31, and 10 per cent 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 ongoing major merger and an upcoming minor merger, which is expected to end up in a single massive galaxy by z ∼ 2.5.

Original languageEnglish
Pages (from-to)L18-L23
JournalMonthly Notices of the Royal Astronomical Society: Letters
Volume491
Issue number1
DOIs
Publication statusPublished - 2020 Jan 1

Keywords

  • Dynamics
  • Galaxies: evolution
  • Galaxies: high-redshift
  • Galaxies: interactions
  • Galaxies: kinematics

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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