ARE SOME MILKY WAY GLOBULAR CLUSTERS HOSTED BY UNDISCOVERED GALAXIES?
The confirmation of a globular cluster (GC) in the recently discovered ultrafaint galaxy Eridanus II (Eri II) motivated us to examine the question posed in the title. After estimating the halo mass of Eri II using a published stellar mass-halo mass relation, the one GC in this galaxy supports extend...
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ndltd-arizona.edu-oai-arizona.openrepository.com-10150-6214032016-11-24T03:00:36Z ARE SOME MILKY WAY GLOBULAR CLUSTERS HOSTED BY UNDISCOVERED GALAXIES? Zaritsky, Dennis Crnojević, Denija Sand, David J. Univ Arizona, Steward Observ dark matter Galaxy: halo globular clusters: general The confirmation of a globular cluster (GC) in the recently discovered ultrafaint galaxy Eridanus II (Eri II) motivated us to examine the question posed in the title. After estimating the halo mass of Eri II using a published stellar mass-halo mass relation, the one GC in this galaxy supports extending the relationship between the number of GCs hosted by a galaxy and the galaxy's total mass about two orders of magnitude in stellar mass below the previous limit. For this empirically determined specific frequency of between 0.06 and 0.39 GCs per 10(9)M(circle dot) of total mass, the surviving Milky Way (MW) subhalos with masses smaller than 10(10)M(circle dot) could host as many as 5-31 GCs, broadly consistent with the actual population of outer halo MW GCs, although matching the radial distribution in detail remains a challenge. Using a subhalo mass function from published high-resolution numerical simulations and a Poissonian model for populating those halos with the aforementioned empirically constrained frequency, we find that about 90% of these GCs lie in lower-mass subhalos than that of Eri II. From what we know about the stellar mass-halo mass function, the subhalo mass function, and the mass-normalized GC specific frequency, we conclude that some of the MW's outer halo GCs are likely to be hosted by undetected subhalos with extremely modest stellar populations. 2016-07-15 Article ARE SOME MILKY WAY GLOBULAR CLUSTERS HOSTED BY UNDISCOVERED GALAXIES? 2016, 826 (1):L9 The Astrophysical Journal 2041-8213 10.3847/2041-8205/826/1/L9 http://hdl.handle.net/10150/621403 http://arizona.openrepository.com/arizona/handle/10150/621403 The Astrophysical Journal en http://stacks.iop.org/2041-8205/826/i=1/a=L9?key=crossref.d8e4a98329d4fdb127cbaa89d67e8bde © 2016. The American Astronomical Society. All rights reserved. IOP PUBLISHING LTD |
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en |
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topic |
dark matter Galaxy: halo globular clusters: general |
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dark matter Galaxy: halo globular clusters: general Zaritsky, Dennis Crnojević, Denija Sand, David J. ARE SOME MILKY WAY GLOBULAR CLUSTERS HOSTED BY UNDISCOVERED GALAXIES? |
description |
The confirmation of a globular cluster (GC) in the recently discovered ultrafaint galaxy Eridanus II (Eri II) motivated us to examine the question posed in the title. After estimating the halo mass of Eri II using a published stellar mass-halo mass relation, the one GC in this galaxy supports extending the relationship between the number of GCs hosted by a galaxy and the galaxy's total mass about two orders of magnitude in stellar mass below the previous limit. For this empirically determined specific frequency of between 0.06 and 0.39 GCs per 10(9)M(circle dot) of total mass, the surviving Milky Way (MW) subhalos with masses smaller than 10(10)M(circle dot) could host as many as 5-31 GCs, broadly consistent with the actual population of outer halo MW GCs, although matching the radial distribution in detail remains a challenge. Using a subhalo mass function from published high-resolution numerical simulations and a Poissonian model for populating those halos with the aforementioned empirically constrained frequency, we find that about 90% of these GCs lie in lower-mass subhalos than that of Eri II. From what we know about the stellar mass-halo mass function, the subhalo mass function, and the mass-normalized GC specific frequency, we conclude that some of the MW's outer halo GCs are likely to be hosted by undetected subhalos with extremely modest stellar populations. |
author2 |
Univ Arizona, Steward Observ |
author_facet |
Univ Arizona, Steward Observ Zaritsky, Dennis Crnojević, Denija Sand, David J. |
author |
Zaritsky, Dennis Crnojević, Denija Sand, David J. |
author_sort |
Zaritsky, Dennis |
title |
ARE SOME MILKY WAY GLOBULAR CLUSTERS HOSTED BY UNDISCOVERED GALAXIES? |
title_short |
ARE SOME MILKY WAY GLOBULAR CLUSTERS HOSTED BY UNDISCOVERED GALAXIES? |
title_full |
ARE SOME MILKY WAY GLOBULAR CLUSTERS HOSTED BY UNDISCOVERED GALAXIES? |
title_fullStr |
ARE SOME MILKY WAY GLOBULAR CLUSTERS HOSTED BY UNDISCOVERED GALAXIES? |
title_full_unstemmed |
ARE SOME MILKY WAY GLOBULAR CLUSTERS HOSTED BY UNDISCOVERED GALAXIES? |
title_sort |
are some milky way globular clusters hosted by undiscovered galaxies? |
publisher |
IOP PUBLISHING LTD |
publishDate |
2016 |
url |
http://hdl.handle.net/10150/621403 http://arizona.openrepository.com/arizona/handle/10150/621403 |
work_keys_str_mv |
AT zaritskydennis aresomemilkywayglobularclustershostedbyundiscoveredgalaxies AT crnojevicdenija aresomemilkywayglobularclustershostedbyundiscoveredgalaxies AT sanddavidj aresomemilkywayglobularclustershostedbyundiscoveredgalaxies |
_version_ |
1718398094241955840 |