Abstract

Context. The evolution of galaxies depends on their interaction with the surrounding environment. Ultra-diffuse galaxies (UDGs) have been found in large numbers in clusters. We detected a few star-forming blobs in the VESTIGE survey, located at ∼5 kpc from a UDG, namely NGVS 3543, in association with an HI gas cloud AGC 226178, suggesting a recent interaction between this low-surface-brightness system and the surrounding cluster environment. Aims. We use a complete set of multi-frequency data including deep optical, UV, and narrow-band Hα imaging and HI data to understand the formation process that gave birth to this peculiar system. Methods. For this purpose, we measured (i) the multi-wavelength radial surface brightness profiles of NGVS 3543 and compared them to the predictions of spectro-photometric models of galaxy evolution in rich clusters; and (ii) the aperture photometry of the blue regions in the vicinity of NGVS 3543 in order to determine their age and stellar mass. Results. Comparisons of the observations with evolutionary models indicate that NGVS 3543 has undergone a ram-pressure stripping that peaked ∼100 Myr ago, transforming a blue gas-rich UDG into a red gas-poor UDG. Star formation has taken place in the ram pressure stripped gas, the mass of which is ∼108 M⊙, forming star complexes with a typical age of ∼20 Myr and a stellar mass of ∼104 M⊙. Conclusions. These results suggest that we are observing for the first time the ongoing transformation of a gas-rich UDG into a red and quiescent UDG under the effect of a ram-pressure stripping event. The same process could explain the lack of star-forming UDGs in rich environments observed in several nearby clusters.

Highlights

  • The Virgo cluster is one of the richest clusters of galaxies in the nearby Universe, making it a prime candidate for Reduced images are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc. u-strasbg.fr/viz-bin/cat/J/A+A/650/A99Based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-French-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l’Univers of the Centre National de la Recherche Scientifique (CNRS) of France and the University of Hawaii.deep, blind surveys at all wavelengths

  • While our best model was obtained by keeping only three free parameters, we investigate how our results are affected by the peak efficiency ( 0) and the full width at half maximum (FWHM) of the Gaussian used for modelling the rampressure stripping (RPS) event

  • While many mechanisms have been proposed in the literature for the formation of these peculiar families of objects populating nearby clusters (UDGs and almost dark clouds), our results indicate that RPS, already known to be a major process shaping galaxy evolution in young clusters, has recently had a major driving effect in the formation of the Next Generation Virgo cluster Survey (NGVS) 3543 system

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Summary

Introduction

The Virgo cluster is one of the richest clusters of galaxies in the nearby Universe, making it a prime candidate for Reduced images are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc. u-strasbg.fr/viz-bin/cat/J/A+A/650/A99. In an ongoing analysis of a large sample of low-surface-brightness galaxies (LSBs), UDGs as defined by van Dokkum et al (2015), Koda et al (2015), and UDGs as defined by Lim et al (2020) in the Virgo cluster (Junais et al, in prep.), we noticed blue knots and diffuse emission within a few kiloparsecs of one of our targets, the UDG NGVSJ12:46:41.73+10:23:10.4, which hereafter we refer to as NGVS 3543 (based on the position of this galaxy in the NGVS catalog), as well as Hα emission in the narrowband image taken during the VESTIGE survey (Fig. 1). With other VESTIGE and NGVS studies, we assume the Virgo cluster to be at a distance of 16.5 Mpc (Gavazzi et al 1999; Mei et al 2007; Blakeslee et al 2009), with a projected angular scale of 80 pc arcsec−1

Data and measurements
Radial profiles of NGVS 3543
Selection of blue regions
Ultraviolet selection
G D 16
Galaxy evolution models with ram-pressure stripping applied to NGVS 3543
Stellar mass and age of the blue knots
Ages and stellar masses of the young regions
Gradients along the tail
An UDG undergoing a RPS event
Formation of an almost-dark object
The possibility of tidal interactions
Findings
Summary
Conclusions
Full Text
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