The first detection of ultra-diffuse galaxies in the Hydra I cluster from the VEGAS survey

In this paper, we report the discovery of 27 low-surface brightness galaxies, of which 12 are candidates for ultra-diffuse galaxies (UDG) in the Hydra I cluster, based on deep observations taken as part of the VST Early-type Galaxy Survey (VEGAS). This first sample of UDG candidates in the Hydra I cluster represents an important step in our project that aims to enlarge the number of confirmed UDGs and, through study of statistically relevant samples, constrain the nature and formation of UDGs. This study presents the main properties of this class of galaxies in the Hydra I cluster. For all UDGs, we analysed the light and colour distribution, and we provide a census of the globular cluster (GC) systems around them. Given the limitations of a reliable GC selection based on two relatively close optical bands only, we find that half of the UDG candidates have a total GC population consistent with zero. Of the other half, two galaxies have a total population larger than zero at 2σ level. We estimate the stellar mass, the total number of GCs, and the GC specific frequency (SN). Most of the candidates span a range of stellar masses of 107 − 108 M⊙. Based on the GC population of these newly discovered UDGs, we conclude that most of these galaxies have a standard or low dark matter content, with a halo mass of ≤1010 M⊙.

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The formation of ultradiffuse galaxies in clusters

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa854 ◽

2020 ◽

Vol 494 (2) ◽

pp. 1848-1858 ◽

Cited By ~ 11

Author(s):

Laura V Sales ◽

Julio F Navarro ◽

Louis Peñafiel ◽

Eric W Peng ◽

Sungsoon Lim ◽

...

Keyword(s):

Surface Brightness ◽

Velocity Dispersion ◽

Stellar Mass ◽

Matter Content ◽

Lower Velocity ◽

Large Size ◽

Hydrodynamical Simulation ◽

Low Surface Brightness ◽

Mass Size ◽

Low Surface Brightness Galaxies

ABSTRACT We use the IllustrisTNG cosmological hydrodynamical simulation to study the formation of ultradiffuse galaxies (UDGs) in galaxy clusters. We supplement the simulations with a realistic mass–size relation for galaxies at the time of infall into the cluster, as well as an analytical model to describe the tidally induced evolution of their stellar mass, velocity dispersion, and size. The model assumes ‘cuspy’ NFW haloes and, contrary to recent claims, has no difficulty reproducing the observed number of UDGs in clusters. Our results further suggest that the UDG population consists of a mixture of ‘normal’ low surface brightness galaxies such as those found in the field (‘born’ UDGs, or B-UDGs), as well as a distinct population that owe their large size and low surface brightness to the effects of cluster tides (‘tidal’, or T-UDGs). The simulations indicate that T-UDGs entered the cluster earlier and should be more prevalent than B-UDGs near the cluster centres. T-UDGs should also have, at given stellar mass, lower velocity dispersion, higher metallicities, and lower dark matter content than B-UDGs. Our results suggest that systems like DF-44 are consistent with having been born as UDGs, while others such as DF2, DF4, and VLSB-D are possibly extreme T-UDG examples.

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A rare example of low surface-brightness radio lobes in a gas-rich early-type galaxy: the story of NGC 3998

Astronomy and Astrophysics ◽

10.1051/0004-6361/201628282 ◽

2016 ◽

Vol 592 ◽

pp. A94 ◽

Cited By ~ 7

Author(s):

Bradley S. Frank ◽

Raffaella Morganti ◽

Tom Oosterloo ◽

Kristina Nyland ◽

Paolo Serra

Keyword(s):

Surface Brightness ◽

Early Type ◽

Low Surface Brightness ◽

Early Type Galaxy

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Dwarf Galaxies in the MATLAS Survey: Hubble Space Telescope Observations of the Globular Cluster System in the Ultra-diffuse Galaxy MATLAS-2019

The Astrophysical Journal ◽

10.3847/1538-4357/ac2831 ◽

2021 ◽

Vol 923 (1) ◽

pp. 9

Author(s):

Oliver Müller ◽

Patrick R. Durrell ◽

Francine R. Marleau ◽

Pierre-Alain Duc ◽

Sungsoon Lim ◽

...

Keyword(s):

Dark Matter ◽

Globular Clusters ◽

Hubble Space Telescope ◽

Matter Content ◽

Dark Matter Halo ◽

Low Surface Brightness ◽

Specific Frequency ◽

Low Surface Brightness Galaxies ◽

Superior Image Quality

Abstract Ultra-diffuse galaxies (UDGs) are very-low-surface-brightness galaxies with large effective radii. Spectroscopic measurements of a few UDGs have revealed a low dark-matter content based on the internal motion of stars or globular clusters (GCs). This is in contrast to the large number of GCs found for these systems, from which it would be expected to correspond to a large dark-matter halo mass. Here we present HST+ACS observations for the UDG MATLAS-2019 in the NGC 5846 group. Using the F606W and F814W filters, we trace the GC population two magnitudes below the peak of the GC luminosity function (GCLF). Employing Bayesian considerations, we identify 26 ± 6 GCs associated with the dwarf, yielding a large specific frequency of S N = 58 ± 14. We use the turnover of the GCLF to derive a distance of 21 ± 2 Mpc, which is consistent with the NGC 5846 group of galaxies. Due to the superior image quality of the HST, we are able to resolve the GCs and measure their sizes, which are consistent with the sizes of GCs around Local Group galaxies. Using the linear relation between the total mass of galaxies and of GCs, we derive a halo mass of 0.9 ± 0.2 × 1011 M ⊙ (M ⊙/L ⊙ > 1000). The high abundance of GCs, together with the small uncertainties, make MATLAS-2019 one of the most extreme UDGs, which likely sets an upper limit of the number of GCs for UDGs.

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A tidal tale: detection of several stellar streams in the environment of NGC 1052

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935463 ◽

2019 ◽

Vol 624 ◽

pp. L6 ◽

Cited By ~ 17

Author(s):

Oliver Müller ◽

R. Michael Rich ◽

Javier Román ◽

Mustafa K. Yıldız ◽

Michal Bílek ◽

...

Keyword(s):

Dark Matter ◽

Galaxy Formation ◽

Surface Brightness ◽

Dwarf Galaxy ◽

Early Type ◽

Tidal Interaction ◽

Low Surface Brightness ◽

Stellar Streams ◽

Early Type Galaxy ◽

Band Image

The possible existence of two dark-matter-free galaxies (NGC 1052-DF2 and NGC 1052-DF4) in the field of the early-type galaxy NGC 1052 presents a challenge to theories of dwarf galaxy formation according to the current cosmological paradigm. We carried out a search for signatures of past interactions connected to the putative hosts of NGC 1052-DF2 and NGC 1052-DF4 using a very deep L-band image obtained with the 0.7 m Jeanne Rich telescope that reach a surface brightness limit of 28.5 mag arcsec−2 in the r band. We found several low-surface brightness features, possibly consistent with an ongoing merger history in this group. We find a tidal interaction between NGC 1052 and NGC 1047, confirming a physical association. Furthermore, we find a stellar loop around NGC 1052 in the direction of NGC 1042 and a stellar stream pointing in the direction of NGC 1052-DF2, but they are not directly connected. We find no evidence for a recent tidal interaction for NGC 1052-DF2 and NGC 1052-DF4. No LSB features have been uncovered around the spiral galaxy NGC 1042, which leaves the association (physical or projected) between NGC 1052 and NGC 1042 ambiguous, although they have similar radial velocities. Their association will only be established when accurate distances to both objects have been measured.

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The properties of a large sample of low surface brightness galaxies from SDSS

Proceedings of the International Astronomical Union ◽

10.1017/s1743921310002802 ◽

2009 ◽

Vol 5 (S262) ◽

pp. 213-216

Author(s):

Y. C. Liang ◽

G. H. Zhong ◽

X. Y. Chen ◽

D. Gao ◽

F. Hammer ◽

...

Keyword(s):

Surface Brightness ◽

Stellar Populations ◽

Disk Galaxies ◽

Large Sample ◽

Central Surface ◽

Low Surface Brightness ◽

Stellar Masses ◽

Low Surface Brightness Galaxies ◽

Lsb Galaxies

AbstractA large sample of low surface brightness (LSB) disk galaxies is selected from SDSS with B-band central surface brightness μ0(B) from 22 to 24.5 mag arcsec−2. Some of their properties are studied, such as magnitudes, surface brightness, scalelengths, colors, metallicities, stellar populations, stellar masses and multiwavelength SEDs from UV to IR etc. These properties of LSB galaxies have been compared with those of the galaxies with higher surface brightnesses. Then we check the variations of these properties following surface brightness.

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A Survey for Low Surface Brightness Galaxies around M31. II. The Newly Discovered Dwarf Andromeda VI

The Astronomical Journal ◽

10.1086/301023 ◽

1999 ◽

Vol 118 (3) ◽

pp. 1220-1229 ◽

Cited By ~ 36

Author(s):

Taft E. Armandroff ◽

George H. Jacoby ◽

James E. Davies

Keyword(s):

Surface Brightness ◽

Low Surface Brightness ◽

Low Surface Brightness Galaxies

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Ultradiffuse galaxies in the IC 1459 group from the VEGAS survey

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa1111 ◽

2020 ◽

Vol 494 (4) ◽

pp. 5293-5297

Author(s):

Duncan A Forbes ◽

Bililign T Dullo ◽

Jonah Gannon ◽

Warrick J Couch ◽

Enrichetta Iodice ◽

...

Keyword(s):

Globular Clusters ◽

Compact Objects ◽

Early Type ◽

Group Members ◽

Measurement Uncertainties ◽

Stellar Masses ◽

Double Nucleus ◽

Early Type Galaxy

ABSTRACT Using deep g, r, i imaging from the VST Early-type GAlaxy Survey (VEGAS), we have searched for ultradiffuse galaxies (UDGs) in the IC 1459 group. Assuming they are group members, we identify nine galaxies with physical sizes and surface brightnesses that match the UDG criteria within our measurement uncertainties. They have mean colours of g − i = 0.6 and stellar masses of ∼108 M⊙. Several galaxies appear to have associated systems of compact objects, e.g. globular clusters. Two UDGs contain a central bright nucleus, with a third UDG revealing a remarkable double nucleus. This appears to be the first reported detection of a double nucleus in a UDG – its origin is currently unclear.

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