A Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE)

Abstract

Context. Low-surface-brightness galaxies (LSBs) contribute to a significant fraction of all the galaxies in the Universe. Ultra-diffuse galaxies (UDGs) form a subclass of LSBs that has attracted a lot of attention in recent years (although its definition may vary between studies). Although UDGs are found in large numbers in galaxy clusters, groups, and in the field, their formation and evolution are still very much debated. Aims. Using a comprehensive set of multiwavelength data from the NGVS (optical), VESTIGE (Hα narrowband), and GUViCS (UV) surveys, we studied a sample of 64 diffuse galaxies and UDGs in the Virgo cluster to investigate their formation history. Methods. We analyzed the photometric colors and surface-brightness profiles of these galaxies and then compared them to models of galaxy evolution, including ram-pressure stripping (RPS) events to infer any possible strong interactions with the hot cluster gas in the past. Results. While our sample consists mainly of red LSBs, which is typical in cluster environments, we found evidence of a color variation with the cluster-centric distance. Blue, H i-bearing, star-forming diffuse galaxies are found at larger distances from the cluster center than the rest of the sample. The comparison of our models with multifrequency observations suggests that most of the galaxies of the sample might have undergone a strong RPS event in their lifetime, on average 1.6 Gyr ago (with a large dispersion, and RPS still ongoing for some of them). This process resulted in the transformation of initially gas-rich diffuse blue galaxies into gas-poor and red ones that form the dominant population now, the more extreme UDGs having undergone the process in a more distant past on average. Conclusions. The RPS in dense environments could be one of the major mechanisms for the formation of the large number of quiescent UDGs we observe in galaxy clusters.

Gas-rich, Field Ultra-diffuse Galaxies Host Few Gobular Clusters

“…The finding that field UDGs have far fewer GCs than most cluster UDGs is in tension with the hypothesis of Junais & Boselli (2022), that blue UDGs in the outskirts of Virgo were previously field UDGs and are now transitioning to become red cluster UDGs. However, it is still possible that ram-pressure stripping of field UDGs may explain a small fraction of cluster UDGs, for example those at the lowest masses, which are less GC-rich (Figure 3).…”

“…have been the progenitors of present-day UDGs in clusters and groups (Leisman et al 2017). More recently, Junais & Boselli (2022) argued that some blue UDGs in the outskirts of the Virgo cluster are being ram-pressure stripped and transforming into the red UDGs typically found in cluster environments. Given that blue UDGs in the field seem to make up a significant fraction of all UDGs (e.g., Jones et al 2018;Prole et al 2019), it is worth addressing the question: Were the UDGs found in present-day clusters and groups once similar to the blue, gas-rich UDGs found in the field?…”

“…However, it is still possible that ram-pressure stripping of field UDGs may explain a small fraction of cluster UDGs, for example those at the lowest masses, which are less GC-rich (Figure 3). An accounting of the GC systems of the Junais & Boselli (2022) sample would help to resolve this ambiguity.…”

AMUSE-Antlia. I. Nuclear X-Ray Properties of Early-type Galaxies in a Dynamically Young Galaxy Cluster

“…The infall of the NGC 3258 subcluster is likely to have caused ram pressure stripping. There is also clear evidence for ram stripping in Fornax (e.g., Jones et al 1997;Su et al 2017bSu et al , 2017Serra et al 2023) and Virgo (e.g., Forman et al 1979;Boselli et al 2014;Su et al 2019;Junais et al 2022). However, these two clusters may be experiencing different stages of ram pressure stripping compared to Antlia.…”

Ultradiffuse Galaxies (UDGs) with Hyper Suprime-Cam. I. Revised Catalog of Coma Cluster UDGs*

“…The denser cluster environment may also play a key role in producing quiescent UDGs. Cluster UDGs may initially form as diffuse galaxies in the same manner as the bluer field UDGs, but have undergone additional quenching by the cluster environment (Penny et al 2011;Jiang et al 2019;Prole et al 2019;Grishin et al 2021;Junais et al 2020). Even within a single galaxy cluster itself, the immediate environment, such as galaxy density, varies and may alter the properties of UDG populations as a function of cluster radius, substructure, and local inhomogeneities.…”