TY - JOUR

T1 - Dwarf Galaxies in the MATLAS Survey

T2 - Hubble Space Telescope Observations of the Globular Cluster System in the Ultra-diffuse Galaxy MATLAS-2019

AU - Mueller, Oliver

AU - Durrell, Patrick R.

AU - Marleau, Francine R.

AU - Duc, Pierre-Alain

AU - Lim, Sungsoon

AU - Posti, Lorenzo

AU - Agnello, Adriano

AU - Sanchez-Janssen, Ruben

AU - Poulain, Melina

AU - Habas, Rebecca

AU - Emsellem, Eric

AU - Paudel, Sanjaya

AU - van der Burg, Remco F. J.

AU - Fensch, Jeremy

PY - 2021/12/7

Y1 - 2021/12/7

N2 - 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 x 10(11) M (circle dot) (M (circle dot)/L (circle dot) > 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.

AB - 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 x 10(11) M (circle dot) (M (circle dot)/L (circle dot) > 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.

KW - GENERATION VIRGO CLUSTER

KW - SURFACE BRIGHTNESS GALAXIES

KW - HALO MASS

KW - PERSEUS CLUSTER

KW - LOCAL GROUP

KW - LAMBDA-CDM

KW - ORIGIN

KW - POPULATIONS

KW - DISCOVERY

KW - ABUNDANCE

U2 - 10.3847/1538-4357/ac2831

DO - 10.3847/1538-4357/ac2831

M3 - Journal article

VL - 923

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1

M1 - 9

ER -