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Circumnuclear Medium around the Central AGN in a Cool-core Cluster, Abell 1644-South

Baek, Junhyun; Chung, Aeree; Edge, Alastair; Rose, Tom; Kim, Jae-Woo; Jung, Taehyun

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Junhyun Baek

Aeree Chung

Tom Rose

Jae-Woo Kim

Taehyun Jung


We present the circumnuclear multiphase gas properties of the brightest cluster galaxy (BCG) in the center of Abell 1644-South (A1644-S). A1644-S is the main cluster in a merging system, which is well known for X-ray hot gas sloshing in its core. The sharply peaked X-ray profile of A1644-S implies the presence of a strongly cooling gas core. In this study, we analyze ALMA 12CO (1–0) data, JVLA H I data, and KaVA 22 GHz data for the central region of A1644-S to probe the potential origin of the cool gas and its role in (re)powering the central active galactic nucleus (AGN). We find CO clumps distributed in an arc shape along the X-ray gas sloshing, which is suggestive of a connection between the cold gas and the hot intracluster medium (ICM). H I and CN are detected in absorption against the AGN continuum emission. The absorption dip is observed at the systemic velocity of the BCG with an extended, redshifted tail. Based on the spatial and spectral configurations of the H I, CN, and CO gases, it is inferred that cool gas spirals into the core of the BCG, which is then fed to the central AGN. Indeed, our KaVA observation reveals a parsec-scale bipolar jet, implying that this AGN could have been (re)powered quite recently. Combining this, we suggest that some cold gas in A1644-S could have been formed from the cooling of the ICM, triggering the activity of the central AGN in the early development of a cool-core cluster.


Baek, J., Chung, A., Edge, A., Rose, T., Kim, J., & Jung, T. (2022). Circumnuclear Medium around the Central AGN in a Cool-core Cluster, Abell 1644-South. Astrophysical Journal, 932(1), Article 64.

Journal Article Type Article
Acceptance Date May 6, 2022
Online Publication Date Jun 16, 2022
Publication Date Jun 10, 2022
Deposit Date Jul 12, 2022
Publicly Available Date Jul 12, 2022
Journal Astrophysical Journal
Print ISSN 0004-637X
Electronic ISSN 1538-4357
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 932
Issue 1
Article Number 64


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Copyright Statement
Original content from this work may be used under the terms<br /> of the Creative Commons Attribution 4.0 licence. Any further<br /> distribution of this work must maintain attribution to the author(s) and the title<br /> of the work, journal citation and DOI.

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