# A titanic interstellar medium ejection from a massive starburst galaxy at redshift 1.4

## Abstract

Feedback-driven winds from star formation or active galactic nuclei might be a relevant channel for the abrupt quenching of star formation in massive galaxies. However, both observations and simulations support the idea that these processes are non-conflictingly co-evolving and self-regulating. Furthermore, evidence of disruptive events that are capable of fast quenching is rare, and constraints on their statistical prevalence are lacking. Here we present a massive starburst galaxy at redshift z = 1.4, which is ejecting 46 ± 13% of its molecular gas mass at a startling rate of 10,000 M yr−1. A broad component that is red-shifted from the galaxy emission is detected in four (low and high J) CO and [C i] transitions and in the ionized phase, which ensures a robust estimate of the expelled gas mass. The implied statistics suggest that similar events are potentially a major star-formation quenching channel. However, our observations provide compelling evidence that this is not a feedback-driven wind, but rather material from a merger that has been probably tidally ejected. This finding challenges some literature studies in which the role of feedback-driven winds might be overstated.

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## Data availability

The ALMA data analysed in this study are publicly available from the ALMA archive (http://almascience.nrao.edu/aq/, Program IDs: 2015.1.00260.S, 2016.1.00171.S and 2019.1.01702.S). The DEIMOS spectrum of the source is also publicly available and can be retrieved through the COSMOS archive (http://cosmos.astro.caltech.edu/).

## Code availability

The ALMA data are processed using a series of GILDAS-based scripts available at https://github.com/1054/Crab.Toolkit.PdBI. The GILDAS software is publicly available at http://www.iram.fr/IRAMFR/GILDAS. The CO and [C i] emission of the source has been modelled with the MICHI2 software, which is publicly available at https://ascl.net/code/v/2533.

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## Acknowledgements

A.P. and E.D. thank A. Renzini for commenting on the manuscript and for useful discussion. A.P. acknowledges funding from Region Île-de-France and an Incoming CEA fellowship from the CEA-Enhanced Eurotalents programme, co-funded by the FP7 Marie-Skłodowska-Curie COFUND programme (grant agreement 600382). A.P. also gratefully acknowledges financial support from the STFC (grants ST/T000244/1 and ST/P000541/1). M.P. acknowledges support from the Comunidad de Madrid through the Atracción de Talento Investigador (grant 2018-T1/TIC-11035). S.J. acknowledges financial support from the Spanish Ministry of Science, Innovation and Universities (MICIU) (grant AYA2017-84061-P), co-financed by FEDER (European Regional Development Funds).

## Author information

Authors

### Contributions

A.P. and E.D. reduced the data, interpreted the results and wrote the paper. All other authors contributed to the observing proposals, to the scientific discussion and elaboration of the results, and commented on the manuscript.

### Corresponding author

Correspondence to Annagrazia Puglisi.

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### Competing interests

The authors declare no competing interests.

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Nature Astronomy thanks the anonymous reviewers for their contribution to the peer review of this work.

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## Extended data

### Extended Data Fig. 1 Spectral energy distribution of ID2299.

Dark grey dots represent the observed multi-wavelength photometry and 1σ errors while dark grey arrows indicate 3σ upper limits. The black solid line is the best-fit spectral energy distribution of the source (SED, see Methods for details). The coloured lines represent individual contributions to the best-fit SED from attenuated stellar emission (orange), dust emission from star formation (dark red), AGN (teal) and radio emission (magenta).

### Extended Data Fig. 2 Amplitude as a function of the uv distance for ID2299.

Different symbols and colours show the amplitude and 1σ error from the various transitions/continua (see legend). The black line is the best-fit Gaussian profile. The grey shaded area highlights the 1σ error associated to this model and it is comparable to the thickness of the black solid line. The size of the best-fit Gaussian profile and 1σ uncertainty are reported in the upper left corner of the plot.

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Puglisi, A., Daddi, E., Brusa, M. et al. A titanic interstellar medium ejection from a massive starburst galaxy at redshift 1.4. Nat Astron (2021). https://doi.org/10.1038/s41550-020-01268-x