The ALMA-CRISTAL survey: Extended [CII] emission in an interacting galaxy system at z ~ 5.5
2024
Online
report
The ALMA [CII] Resolved Ism in STar-forming gALaxies (CRISTAL) survey is a Cycle 8 ALMA Large Programme that studies the cold gas component of high-redshift galaxies. Its sub-arcsecond resolution observations are key to disentangling physical mechanisms that shape galaxies during cosmic dawn. In this paper, we explore the morphology and kinematics of the cold gas, star-forming, and stellar components in the star-forming main-sequence galaxy CRISTAL-05/HZ3, at z = 5.54. Our analysis includes 0.3" spatial resolution (~2 kpc) ALMA observations of the [CII] line. While CRISTAL-05 was previously classified as a single source, our observations reveal that the system is a close interacting pair surrounded by an extended component of carbon-enriched gas. This is imprinted in the disturbed elongated [CII] morphology and the separation of the two components in the position-velocity diagram (~100 km/s). The central region is composed of two components, named C05-NW and C05-SE, with the former being the dominant one. A significant fraction of the [CII] arises beyond the close pair up to 10 kpc, while the regions forming new massive stars and the stellar component seem compact (r_[CII] ~ 4 r_UV), as traced by rest-frame UV and optical imaging obtained with the Hubble Space Telescope and the James Webb Space Telescope. Our kinematic model, using the DYSMALpy software, yields a minor contribution of dark matter of C05-NW within a radius of ~2x Reff. Finally, we explore the resolved [CII]/FIR ratios as a proxy for shock-heating produced by this merger. We argue that the extended [CII] emission is mainly caused by the merger, which could not be discerned with lower-resolution observations. Our work emphasizes the need for high-resolution observations to fully characterize the dynamic stages of infant galaxies and the physical mechanisms that drive the metal enrichment of the circumgalactic medium.
Comment: Submitted to A&A - comments are welcome! - 19 pages, 13 figures
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The ALMA-CRISTAL survey: Extended [CII] emission in an interacting galaxy system at z ~ 5.5
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Autor/in / Beteiligte Person: | Posses, A. ; Aravena, M. ; González-López, J. ; Schreiber, N. M. Förster ; Liu, D. ; Lee, L. ; Solimano, M. ; Díaz-Santos, T. ; Assef, R. J. ; Barcos-Muñoz, L. ; Bovino, S. ; Bowler, R. A. A. ; Rivera, G. Calistro ; da Cunha, E. ; Davies, R. L. ; Killi, M. ; De Looze, I. ; Ferrara, A. ; Fisher, D. B. ; Herrera-Camus, R. ; Ikeda, R. ; Lambert, T. ; Li, J. ; Lutz, D. ; Mitsuhashi, I. ; Palla, M. ; Relaño, M. ; Spilker, J. ; Naab, T. ; Tadaki, K. ; Telikova, K. ; Übler, H. ; van der Giessen, S. ; Villanueva, V. |
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Veröffentlichung: | 2024 |
Medientyp: | report |
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