Ultra Diffuse Galaxies in clusters : the peculiar gas loss of VCC 1964

Fuente: arXiv
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Autores principales: Taylor, Rhys, Partík, Vojtech, Minchin, Robert
Formato: Preprint
Publicado: 2026
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author Taylor, Rhys
Partík, Vojtech
Minchin, Robert
author_facet Taylor, Rhys
Partík, Vojtech
Minchin, Robert
contents Context : Ultra Diffuse Galaxies are low surface brightness systems which have been detected in HI in the field, where their line widths sometimes indicate significant dark matter deficits. They are rarely detected in HI in clusters, making their dynamical properties difficult to assess. The relation between field and cluster populations is unclear. Aims : Detecting UDGs entering a cluster could give important clues to their evolution, both in terms of their dynamics but also as to whether they are structurally similar - i.e. if cluster UDGs are generally the same as field UDGs except with less gas and an older stellar population. Methods : We use data from two deep Arecibo surveys, the Arecibo Galaxy Environment Survey and the Widefield Arecibo Virgo Environment Survey, to measure the gas content of the UDG-candidate VCC 1964. Optical properties are quantified from the Sloan Digital Sky Survey and DESI Legacy Surveys. Results : We find a significant 9 kpc offset between the HI and optical components of VCC 1964, no evidence of asymmetry in the HI, and only a modest deficiency level. This suggests a wholesale displacement of the gas content. The line width is 4-5 sigma deviant from the baryonic and over 6 sigma deviant from the optical forms of the Tully-Fisher relation. The optical component is blue and smooth. Conclusions : VCC 1964 is consistent with a UDG experiencing gas displacement due to ram pressure as it enters the cluster for the first time. Intriguingly, its dynamics imply a significant dark matter deficit, however we cannot rule out that this may be due to the gas being displaced out of equilibrium.
format Preprint
id arxiv_https___arxiv_org_abs_2601_05948
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Ultra Diffuse Galaxies in clusters : the peculiar gas loss of VCC 1964
Taylor, Rhys
Partík, Vojtech
Minchin, Robert
Astrophysics of Galaxies
Context : Ultra Diffuse Galaxies are low surface brightness systems which have been detected in HI in the field, where their line widths sometimes indicate significant dark matter deficits. They are rarely detected in HI in clusters, making their dynamical properties difficult to assess. The relation between field and cluster populations is unclear. Aims : Detecting UDGs entering a cluster could give important clues to their evolution, both in terms of their dynamics but also as to whether they are structurally similar - i.e. if cluster UDGs are generally the same as field UDGs except with less gas and an older stellar population. Methods : We use data from two deep Arecibo surveys, the Arecibo Galaxy Environment Survey and the Widefield Arecibo Virgo Environment Survey, to measure the gas content of the UDG-candidate VCC 1964. Optical properties are quantified from the Sloan Digital Sky Survey and DESI Legacy Surveys. Results : We find a significant 9 kpc offset between the HI and optical components of VCC 1964, no evidence of asymmetry in the HI, and only a modest deficiency level. This suggests a wholesale displacement of the gas content. The line width is 4-5 sigma deviant from the baryonic and over 6 sigma deviant from the optical forms of the Tully-Fisher relation. The optical component is blue and smooth. Conclusions : VCC 1964 is consistent with a UDG experiencing gas displacement due to ram pressure as it enters the cluster for the first time. Intriguingly, its dynamics imply a significant dark matter deficit, however we cannot rule out that this may be due to the gas being displaced out of equilibrium.
title Ultra Diffuse Galaxies in clusters : the peculiar gas loss of VCC 1964
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2601.05948