2020AJ....159...56B -
Astron. J., 159, 56-56 (2020/February-0)
High-precision dark halo virial masses from globular cluster numbers: implications for globular cluster formation and galaxy assembly.
BURKERT A. and FORBES D.A.
Abstract (from CDS):
We confirm that the number of globular clusters (GCs), NGC, is an excellent tracer of their host galaxy's halo virial mass, Mvir. The simple linear relation Mvir = 5 x 109 M☉ x NGC fits the data perfectly from Mvir = 1010 M☉ to Mvir = 2 x 1015 M☉. This result is independent of galaxy morphology and extends statistically into the dwarf galaxy regime with Mvir = 108-1010 M☉, including the extreme ultra diffuse galaxy DF44. As this correlation does not depend on GC mass, it is ideally suited for high-precision determinations of Mvir. The linearity is most simply explained by cosmological merging of a high-redshift halo seed population that hosted on average one GC per 5 x 108 M☉ of dark matter. We show that hierarchical merging is also extremely powerful in restoring a linear correlation and erasing signatures of even a strong secular evolution of GC systems. The cosmological merging scenario also implies a strong decline of the scatter in NGC with increasing virial mass δNGC/NGC∼Mvir–1/2 in contrast with the observations that show a roughly constant scatter, independent of virial mass. This discrepancy can be explained if errors in determining virial masses from kinematical tracers and gravitational lensing are on the order of a factor of 2. GCs in dwarf satellite galaxies pose a serious problem for high-redshift GC formation scenarios; the dark halo masses of dwarf galaxies hosting GCs therefore might need to be an order of magnitude larger than currently estimated.
Abstract Copyright:
© 2020. The American Astronomical Society. All rights reserved.
Journal keyword(s):
Galaxy stellar halos - Globular star clusters - Galaxy dark matter halos
Simbad objects:
9
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