The ALPINE-ALMA [CII] survey: Survey strategy, observations and sample properties of 118 star-forming galaxies at $4 < z < 6$

O. Le Fèvre (1) , M. Béthermin (1) , A. Faisst , P. Capak , P. Cassata , J.D. Silverman , D. Schaerer (2) , L. Yan , G.C. Jones , R. Amorin , S. Bardelli , M. Boquien , A. Cimatti , M. Dessauges-Zavadsky , M. Giavalisco , N.P. Hathi , Y. Fudamoto , S. Fujimoto , M. Ginolfi , C. Gruppioni , S. Hemmati , E. Ibar , A. Koekemoer , Y. Khusanova (1) , G. Lagache (1) , B.C. Lemaux , F. Loiacono , R. Maiolino , C. Mancini , D. Narayanan , L. Morselli , Hugo Méndez-Hernàndez , P.A. Oesch , F. Pozzi , M. Romano , D. Riechers , N. Scoville , M. Talia , L.A.M. Tasca (1) , R. Thomas , S. Toft , L. Vallini , D. Vergani , F. Walter , G. Zamorani , E. Zucca

1 LAM - Laboratoire d'Astrophysique de Marseille
2 IRAP - Institut de recherche en astrophysique et planétologie

The ALMA-ALPINE [CII] survey is aimed at characterizing the properties of a sample of normal star-forming galaxies (SFGs). The ALMA Large Program to INvestigate (ALPINE) features 118 galaxies observed in the [CII]-158 μm line and far infrared (FIR) continuum emission during the period of rapid mass assembly, right after the end of the HI reionization, at redshifts of 4 <  z <  6. We present the survey science goals, the observational strategy, and the sample selection of the 118 galaxies observed with ALMA, with an average beam minor axis of about 0.85″, or ∼5 kpc at the median redshift of the survey. The properties of the sample are described, including spectroscopic redshifts derived from the UV-rest frame, stellar masses, and star-formation rates obtained from a spectral energy distribution (SED) fitting. The observed properties derived from the ALMA data are presented and discussed in terms of the overall detection rate in [CII] and FIR continuum, with the observed signal-to-noise distribution. The sample is representative of the SFG population in the main sequence at these redshifts. The overall detection rate in [CII] is 64% for a signal-to-noise ratio (S/N) threshold larger than 3.5 corresponding to a 95% purity (40% detection rate for S/N >  5). Based on a visual inspection of the [CII] data cubes together with the large wealth of ancillary data, we find a surprisingly wide range of galaxy types, including 40% that are mergers, 20% extended and dispersion-dominated, 13% compact, and 11% rotating discs, with the remaining 16% too faint to be classified. This diversity indicates that a wide array of physical processes must be at work at this epoch, first and foremost, those of galaxy mergers. This paper sets a reference sample for the gas distribution in normal SFGs at 4 <  z <  6, a key epoch in galaxy assembly, which is ideally suited for studies with future facilities, such as the James Webb Space Telescope (JWST) and the Extremely Large Telescopes (ELTs).Key words: galaxies: evolution / galaxies: star formation / galaxies: formation

Mots clés: galaxies: evolution; galaxies: star formation; galaxies: formation

Domaines: Astrophysique [astro-ph]

O. Le Fèvre, M. Béthermin, A. Faisst, P. Capak, P. Cassata, et al.. The ALPINE-ALMA [CII] survey: Survey strategy, observations and sample properties of 118 star-forming galaxies at $4 < z < 6$. Astronomy and Astrophysics - A&A, 2020, 643, pp.A1. ⟨10.1051/0004-6361/201936965⟩. ⟨hal-02432539⟩