The number of globular clusters around the iconic UDG DF44 is as expected for dwarf galaxies. (arXiv:2006.14630v1 [astro-ph.GA])

The number of globular clusters around the iconic UDG DF44 is as expected for dwarf galaxies. (arXiv:2006.14630v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Saifollahi_T/0/1/0/all/0/1">Teymoor Saifollahi</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Trujillo_I/0/1/0/all/0/1">Ignacio Trujillo</a> (2 and 3), <a href="http://arxiv.org/find/astro-ph/1/au:+Beasley_M/0/1/0/all/0/1">Michael A. Beasley</a> (2 and 3), <a href="http://arxiv.org/find/astro-ph/1/au:+Peletier_R/0/1/0/all/0/1">Reynier F. Peletier</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Knapen_J/0/1/0/all/0/1">Johan H. Knapen</a> (2 and 3) ((1) Kapteyn Astronomical Institute, (2) Instituto de Astrof&#xed;sica de Canarias, (3) Departamento de Astrof&#xed;sica, Universidad de La Laguna)

There is a growing consensus that the vast majority of ultra-diffuse galaxies
(UDGs) are dwarf galaxies. However, there remain a few UDGs that seem to be
special in terms of their globular cluster (GC) systems. In particular,
according to some authors, certain UDGs exhibit large GC populations when
compared to expectations from their stellar (or total) mass. Among these
special UDGs, DF44 in the Coma cluster is one of the better-known examples.
DF44 has been claimed to have a relatively high number of GCs,
$N_{GC}=74^{+18}_{-18}$, for a stellar mass of only $3times 10^8$ $M_{ odot
}$. In this paper we revisit this number, and, contrary to previous results,
find $N_{GC}=19^{+5}_{-5}$. Making use of the $M_{rm GC} – M_{rm halo}$
relation, this number of GCs suggests a dark matter halo mass of
$M_{halo}=1.0^{+0.3}_{-0.3} times 10^{11} M_{odot}$, a value which is
consistent with the expected total mass for DF44 based on its velocity
dispersion, $sigma=33^{+3}_{-3}$ km s$^{-1}$. We conclude that the number of
GCs around DF44 is as expected for regular dwarf galaxies of similar stellar
mass and DF44 is not extraordinary in this respect.

There is a growing consensus that the vast majority of ultra-diffuse galaxies
(UDGs) are dwarf galaxies. However, there remain a few UDGs that seem to be
special in terms of their globular cluster (GC) systems. In particular,
according to some authors, certain UDGs exhibit large GC populations when
compared to expectations from their stellar (or total) mass. Among these
special UDGs, DF44 in the Coma cluster is one of the better-known examples.
DF44 has been claimed to have a relatively high number of GCs,
$N_{GC}=74^{+18}_{-18}$, for a stellar mass of only $3times 10^8$ $M_{ odot
}$. In this paper we revisit this number, and, contrary to previous results,
find $N_{GC}=19^{+5}_{-5}$. Making use of the $M_{rm GC} – M_{rm halo}$
relation, this number of GCs suggests a dark matter halo mass of
$M_{halo}=1.0^{+0.3}_{-0.3} times 10^{11} M_{odot}$, a value which is
consistent with the expected total mass for DF44 based on its velocity
dispersion, $sigma=33^{+3}_{-3}$ km s$^{-1}$. We conclude that the number of
GCs around DF44 is as expected for regular dwarf galaxies of similar stellar
mass and DF44 is not extraordinary in this respect.

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