Deep kiloparsec view of the molecular gas in a massive star-forming galaxy at cosmic noon

We present deep (∼20 hr), high-angular resolution Atacama Large Millimeter/submillimeter Array (ALMA) observations of the CO (4 − 3) and [CI] (1 − 0) transitions, along with the rest-frame 630 μm dust continuum, in BX610–a massive, main-sequence galaxy at the peak epoch of cosmic star formation ( z = 2.21). Combined with deep Very Large Telescope (VLT) SINFONI observations of the H α line, we characterize the molecular gas and star formation activity on kiloparsec scales. Our analysis reveals that the excitation of the molecular gas, as traced by the L ′ CO (4−3)/ L ′ [CI](1−0) line luminosity ratio, decreases with increasing galactocentric radius. While the line luminosity ratios in the outskirts are similar to those typically found in main-sequence galaxies at z ∼ 1, the ratios in the central regions of BX610 are comparable to those observed in local starbursts. There is also a giant extra-nuclear star-forming clump in the southwest of BX610 that exhibits high star formation activity, molecular gas abundance, and molecular gas excitation. Furthermore, the central region of BX610 is rich in molecular gas ( M mol / M ⋆ ≈ 1); however, at the current level of star formation activity, such molecular gas is expected to be depleted in ∼450 Myr. This, along with recent evidence for rapid inflow toward the center, suggests that BX610 may be experiencing an evolutionary phase often referred to as wet compaction, which is expected to lead to central gas depletion and subsequent inside-out quenching of star formation activity.

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Publication Details

Journal
Astronomy and Astrophysics
Published
2025-03-11
DOI
https://doi.org/10.1051/0004-6361/202452652
Citations
2
Primary Topic
Galaxies: Formation, Evolution, Phenomena
Type
article
Field-Weighted Citation Impact
2.31

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article

Deep kiloparsec view of the molecular gas in a massive star-forming galaxy at cosmic noon

A. Renzini, R. Genzel, Vicente Villanueva, Rodrigo Herrera-Camus et al.
2 citations
Astronomy and Astrophysics
Galaxies: Formation, Evolution, Phenomena
2.31
article

Deep kiloparsec view of the molecular gas in a massive star-forming galaxy at cosmic noon

A. Renzini, R. Genzel, Vicente Villanueva, Rodrigo Herrera-Camus, Alberto D. Bolatto, Hannah Übler, Daizhong Liu, L. J. Tacconi, N. M. Förster Schreiber, Sebastián Arriagada-Neira, Minju Lee, Jianhang Chen, Giulia Tozzi
article en
2 citations

Abstract

We present deep (∼20 hr), high-angular resolution Atacama Large Millimeter/submillimeter Array (ALMA) observations of the CO (4 − 3) and [CI] (1 − 0) transitions, along with the rest-frame 630 μm dust continuum, in BX610–a massive, main-sequence galaxy at the peak epoch of cosmic star formation ( z = 2.21). Combined with deep Very Large Telescope (VLT) SINFONI observations of the H α line, we characterize the molecular gas and star formation activity on kiloparsec scales. Our analysis reveals that the excitation of the molecular gas, as traced by the L ′ CO (4−3)/ L ′ [CI](1−0) line luminosity ratio, decreases with increasing galactocentric radius. While the line luminosity ratios in the outskirts are similar to those typically found in main-sequence galaxies at z ∼ 1, the ratios in the central regions of BX610 are comparable to those observed in local starbursts. There is also a giant extra-nuclear star-forming clump in the southwest of BX610 that exhibits high star formation activity, molecular gas abundance, and molecular gas excitation. Furthermore, the central region of BX610 is rich in molecular gas ( M mol / M ⋆ ≈ 1); however, at the current level of star formation activity, such molecular gas is expected to be depleted in ∼450 Myr. This, along with recent evidence for rapid inflow toward the center, suggests that BX610 may be experiencing an evolutionary phase often referred to as wet compaction, which is expected to lead to central gas depletion and subsequent inside-out quenching of star formation activity.

Astronomy and AstrophysicsVol. 696
University of Concepción (CL), Chinese Academy of Sciences (CN), Purple Mountain Observatory (CN), Millennium Science Initiative (CL), Max Planck Institute for Extraterrestrial Physics (DE), Millennium Nucleus of Ion Channel Associated Diseases (CL), Millenium Nucleus for Planet Formation (CL), Osservatorio Astronomico di Padova (IT), University of Maryland, College Park (US), Technical University of Denmark (DK)
National Science Foundation, National Aeronautics and Space Administration, Space Telescope Science Institute, National Radio Astronomy Observatory, European Commission, Korea Astronomy and Space Science Institute, Max-Planck-Gesellschaft, European Southern Observatory, Universidad de Concepción, National Astronomical Observatory of Japan, Agencia Nacional de Investigación y Desarrollo, National Science and Technology Council, National Institutes of Natural Sciences
Openalex Percentile: Top 13%
Galaxies: Formation, Evolution, Phenomena
2.31
DOIOpen Access PDFOpenAlex
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