11 research outputs found
Imprint of the galactic acceleration scale on globular cluster systems: Galaxies in the Fornax Cluster
Dark matter is required in galaxies at galactocentric radii that are larger
than the -radius, which is where the gravitational acceleration generated
by baryons of the galaxy equals the constant ms
known as the galactic acceleration scale. It was found previously for massive
early-type galaxies that the radial number-density profiles of their globular
cluster (GC) systems follow broken power laws and the breaks occur at the
-radii. We have newly analyzed the distribution of GCs around galaxies in
the Fornax cluster in existing photometric catalogs. We found that 1) the
coincidence between -radii and the break radii of globular cluster systems
is valid for early-type galaxies of all masses and, 2) this also applies to the
red and blue sub-populations of GCs separately.Comment: 3 pages, 1 figure. To be published in Memorie della SAI
The galactic acceleration scale is imprinted on globular cluster systems of early-type galaxies of most masses and on red and blue globular cluster subpopulations
Context. Globular clusters carry information about the formation histories
and gravitational fields of their host galaxies. B\'ilek et al. (2019, BSR19
hereafter) reported that the radial profiles of volume number density of GCs in
GC systems (GCS) follow broken power laws, while the breaks occur approximately
at the radii. These are the radii at which the gravitational fields of
the galaxies equal the galactic acceleration scale ms known from the radial acceleration relation or the MOND
theory of modified dynamics.
Aims. Our main goals here are to explore whether the results of BSR19 hold
true for galaxies of a wider mass range and for the red and blue GCs
sub-populations.
Methods. We exploited catalogs of photometric GC candidates in the Fornax
galaxy cluster based on ground and space observations and a new catalog of
spectroscopic GCs of NGC 1399, the central galaxy of the cluster. For every
galaxy, we obtained the parameters of the broken power law density by fitting
the on-sky distribution of the GC candidates, while allowing for a constant
density of contaminants. The logarithmic stellar masses of our galaxy sample
span 8.0-11.4 .
Results. All investigated GCSs with a sufficient number of members show
broken power-law density profiles. This holds true for the total GC population
and the blue and red subpopulations. The inner and outer slopes and the break
radii agree well for the different GC populations. The break radii agree with
the radii typically within a factor of two for all GC color
subpopulations. The outer slopes correlate better with the radii than
with the galactic stellar masses. The break radii of NGC 1399 vary in azimuth,
such that they are greater toward and against the neighboring galaxy NGC 1404.Comment: 39 pages, ~15 pages main text, 33 figures, 12 tables. Accepted for
publication in A&
Imprint of the galactic acceleration scale on globular cluster systems: Galaxies in the Fornax Cluster
International audienceDark matter is required in galaxies at galactocentric radii that are larger than the -radius, which is where the gravitational acceleration generated by baryons of the galaxy equals the constant ms known as the galactic acceleration scale. It was found previously for massive early-type galaxies that the radial number-density profiles of their globular cluster (GC) systems follow broken power laws and the breaks occur at the -radii. We have newly analyzed the distribution of GCs around galaxies in the Fornax cluster in existing photometric catalogs. We found that 1) the coincidence between -radii and the break radii of globular cluster systems is valid for early-type galaxies of all masses and, 2) this also applies to the red and blue sub-populations of GCs separately
Imprint of the galactic acceleration scale on globular cluster systems: Galaxies in the Fornax Cluster
International audienceDark matter is required in galaxies at galactocentric radii that are larger than the -radius, which is where the gravitational acceleration generated by baryons of the galaxy equals the constant ms known as the galactic acceleration scale. It was found previously for massive early-type galaxies that the radial number-density profiles of their globular cluster (GC) systems follow broken power laws and the breaks occur at the -radii. We have newly analyzed the distribution of GCs around galaxies in the Fornax cluster in existing photometric catalogs. We found that 1) the coincidence between -radii and the break radii of globular cluster systems is valid for early-type galaxies of all masses and, 2) this also applies to the red and blue sub-populations of GCs separately