TY - JOUR
T1 - The ALPINE-ALMA [CII] survey
T2 - Circumgalactic medium pollution and gas mixing by tidal stripping in a merging system at z ∼4.57
AU - Ginolfi, M.
AU - Jones, G. C.
AU - Béthermin, M.
AU - Faisst, A.
AU - Lemaux, B. C.
AU - Schaerer, D.
AU - Fudamoto, Y.
AU - Oesch, P.
AU - Dessauges-Zavadsky, M.
AU - Fujimoto, S.
AU - Carniani, S.
AU - Le Fèvre, O.
AU - Cassata, P.
AU - Silverman, J. D.
AU - Capak, P.
AU - Yan, Lin
AU - Bardelli, S.
AU - Cucciati, O.
AU - Gal, R.
AU - Gruppioni, C.
AU - Hathi, N. P.
AU - Lubin, L.
AU - Maiolino, R.
AU - Morselli, L.
AU - Pelliccia, D.
AU - Talia, M.
AU - Vergani, D.
AU - Zamorani, G.
N1 - Funding Information:
Acknowledgements. The authors would like to thank the anonymous referee for her/his useful suggestions. This paper is based on data obtained with the ALMA Observatory, under Large Program 2017.1.00428.L. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ. G.C.J.and R.M. acknowledge the ERC Advanced Grant 695671 “QUENCH” and support by the Science and Technology Facilities Council (STFC). C.G. and M.T. acknowledge the support from a grant PRIN MIUR 2017. S.C. acknowledges support from the ERC Advanced Grant INTERSTELLAR H2020/740120. The Cosmic Dawn Center is funded by the Danish National Research Foundation under grant No. 140. Some of the material presented in this paper is based upon work supported by the National Science Foundation under Grant No. 1908422. This program receives financial support from the French CNRS-INSU Programme National Cosmolo-gie et Galaxies. This paper is dedicated to the memory of Olivier Le Fèvre, PI of the ALPINE survey.
Publisher Copyright:
© 2020 ESO.
PY - 2020/11/1
Y1 - 2020/11/1
N2 - We present ALMA observations of a merging system at z ∼ 4.57, observed as a part of the ALMA Large Program to INvestigate [CII] at Early times (ALPINE) survey. Combining ALMA [CII]158μm and far-infrared continuum data with multi-wavelength ancillary data, we find that the system is composed of two massive (M∗ 1010M·) star-forming galaxies experiencing a major merger (stellar mass ratio rmass 0.9) at close spatial (∼13 kpc; projected) and velocity (Δv < 300kms-1) separations, and two additional faint narrow [CII]-emitting satellites. The overall system belongs to a larger scale protocluster environment and is coincident to one of its overdensity peaks. Additionally, ALMA reveals the presence of [CII] emission arising from a circumgalactic gas structure, extending up to a diameter-scale of ∼30 kpc. Our morpho-spectral decomposition analysis shows that about 50% of the total flux resides between the individual galaxy components, in a metal-enriched gaseous envelope characterised by a disturbed morphology and complex kinematics. Similarly to observations of shock-excited [CII] emitted from tidal tails in local groups, our results can be interpreted as a possible signature of interstellar gas stripped by strong gravitational interactions, with a possible contribution from material ejected by galactic outflows and emission triggered by star formation in small faint satellites. Our findings suggest that mergers could be an efficient mechanism of gas mixing in the circumgalactic medium around high-z galaxies, and thus play a key role in the galaxy baryon cycle at early epochs.
AB - We present ALMA observations of a merging system at z ∼ 4.57, observed as a part of the ALMA Large Program to INvestigate [CII] at Early times (ALPINE) survey. Combining ALMA [CII]158μm and far-infrared continuum data with multi-wavelength ancillary data, we find that the system is composed of two massive (M∗ 1010M·) star-forming galaxies experiencing a major merger (stellar mass ratio rmass 0.9) at close spatial (∼13 kpc; projected) and velocity (Δv < 300kms-1) separations, and two additional faint narrow [CII]-emitting satellites. The overall system belongs to a larger scale protocluster environment and is coincident to one of its overdensity peaks. Additionally, ALMA reveals the presence of [CII] emission arising from a circumgalactic gas structure, extending up to a diameter-scale of ∼30 kpc. Our morpho-spectral decomposition analysis shows that about 50% of the total flux resides between the individual galaxy components, in a metal-enriched gaseous envelope characterised by a disturbed morphology and complex kinematics. Similarly to observations of shock-excited [CII] emitted from tidal tails in local groups, our results can be interpreted as a possible signature of interstellar gas stripped by strong gravitational interactions, with a possible contribution from material ejected by galactic outflows and emission triggered by star formation in small faint satellites. Our findings suggest that mergers could be an efficient mechanism of gas mixing in the circumgalactic medium around high-z galaxies, and thus play a key role in the galaxy baryon cycle at early epochs.
KW - Galaxies: ISM
KW - Galaxies: evolution
KW - Galaxies: formation
KW - Galaxies: high-redshift
KW - Galaxies: interactions
KW - Intergalactic medium
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U2 - 10.1051/0004-6361/202038284
DO - 10.1051/0004-6361/202038284
M3 - Review article
AN - SCOPUS:85095118459
SN - 0004-6361
VL - 643
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A7
ER -