English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT
  An old, metal-poor globular cluster in Sextans A and the metallicity floor of globular cluster systems

Beasley, M. A., Leaman, R., Gallart, C., Larsen, S. S., Battaglia, G., Monelli, M., et al. (2019). An old, metal-poor globular cluster in Sextans A and the metallicity floor of globular cluster systems. Monthly Notices of the Royal Astronomical Society, 487, 1986-1993.

Item is

Basic

show hide
Genre: Journal Article

Files

show Files

Locators

show
hide
Description:
-

Creators

show
hide
 Creators:
Beasley, Michael A.1, Author
Leaman, Ryan1, Author
Gallart, Carme1, Author
Larsen, Søren S.1, Author
Battaglia, Giuseppina1, Author
Monelli, Matteo1, Author
Pedreros, Mario H.1, Author
Affiliations:
1Max Planck Institute for Astronomy, Max Planck Society and Cooperation Partners, ou_2421692              

Content

show
hide
Free keywords: galaxies: dwarf galaxies: individual: Sextans A galaxies: star clusters: general Astrophysics - Astrophysics of Galaxies
 Abstract: We report the confirmation of an old, metal-poor globular cluster (GC) in the nearby dwarf irregular galaxy Sextans A, the first GC known in this galaxy. The cluster, which we designate as Sextans A-GC1, lies some 4.4 arcmin (~1.8 kpc) to the SW of the galaxy centre and clearly resolves into stars in sub-arcsecond seeing ground-based imaging. We measure an integrated magnitude V = 18.04, corresponding to an absolute magnitude, MV,0 = -7.85. This gives an inferred mass M ~ 1.6 105 M‚òâ, assuming a Kroupa IMF. An integrated spectrum of Sextans A-GC1 reveals a heliocentric radial velocity vhelio = 305 ¬± 15 km s-1, consistent with the systemic velocity of Sextans A. The location of candidate red giant branch stars in the cluster, and stellar population analyses of the cluster's integrated optical spectrum, suggests a metallicity [Fe/H] ~ -2.4, and an age ~9 Gyr. We measure a half-light radius, Rh = 7.6 ¬± 0.2 pc. Normalizing to the galaxy integrated magnitude, we obtain a V-band specific frequency, SN = 2.1. We compile a sample of 1928 GCs in 28 galaxies with spectroscopic metallicities and find that the low metallicity of Sextans A-GC1 is close to a `metallicity floor' at [Fe/H] ~ -2.5 seen in these GC systems that include the Milky Way, M31, M87, and the Large Magellanic Cloud. This metallicity floor appears to hold across 6 dex in host galaxy stellar mass and is seen in galaxies with and without accreted GC subpopulations.

Details

show
hide
Language(s):
 Dates: 2019
 Publication Status: Published in print
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Type: -
 Identifiers: -
 Degree: -

Event

show

Legal Case

show

Project information

show

Source 1

show
hide
Title: Monthly Notices of the Royal Astronomical Society
Source Genre: Journal
 Creator(s):
Affiliations:
Publ. Info: -
Pages: - Volume / Issue: 487 Sequence Number: - Start / End Page: 1986 - 1993 Identifier: -