SYMPHANY- SYnergy of Molecular PHase And Neutral hYdrogen in galaxies in A2626

Tirna Deb; Garrett K. Keating; Nikki Zabel; Alessia Moretti; Cecilia Bacchini; Timothy A Davis; Bianca M. Poggianti; Marco Gullieuszik; Benedetta Vulcani; Yara Jeffé; Neven Tomicic; Toby Brown

arXiv · 2505.15060

SYMPHANY- SYnergy of Molecular PHase And Neutral hYdrogen in galaxies in A2626

Tirna Deb·Garrett K. Keating·Nikki Zabel·Alessia Moretti·Cecilia Bacchini·Timothy A Davis·Bianca M. Poggianti·Marco Gullieuszik·Benedetta Vulcani·Yara Jeffé·Neven Tomicic·Toby Brown

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Abstract

We present an analysis of the molecular and atomic gas properties of 10 spatially resolved galaxies in the A2626 cluster (z = 0.055), observed as part of the SYMPHANY project. Using CO(2-1) observations from ALMA and SMA, together with HI data from MeerKAT, we examine the interplay between gas phases and environmental influences. A joint morphological and kinematic analysis reveals that while the kinematic behavior of HI and CO are often similar, morphologically the atomic gas is more extended compared to centrally concentrated CO distributions, making it more susceptible to environmental stripping. However, we also find evidence for molecular gas asymmetries, disturbed velocity fields, and H2 deficiencies in some galaxies, indicating that H2 reservoirs can also be disrupted in dense environments. Compared to Virgo-a dynamically unrelaxed, non-cool-core cluster-A2626's relaxed, cool-core structure likely results in less intense ram-pressure stripping. This may allow galaxies to retain more atomic gas, while local interactions or pre-processing may still affect the molecular phase, causing relatively low HI deficiencies but high H2 deficiencies in A2626 galaxies. This is also reflected in the higher gas fractions, slightly elevated SFRs, along with shorter depletion timescales (0.3-3 Gyr), implying moderately enhanced star formation efficiency A2626 galaxies. Moreover, the lack of correlation between H2 deficiency and cluster-centric distance or velocity suggests that molecular gas evolution in A2626 may be shaped more by early infall or local interactions than by current cluster location.

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Tirna Deb, Garrett K. Keating, Nikki Zabel, Alessia Moretti, Cecilia Bacchini, Timothy A Davis, Bianca M. Poggianti, Marco Gullieuszik, Benedetta Vulcani, Yara Jeffé, Neven Tomicic, Toby Brown. 2025-05-21. SYMPHANY- SYnergy of Molecular PHase And Neutral hYdrogen in galaxies in A2626. https://arxiv.org/abs/2505.15060

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