No sign (yet) of intergalactic globular clusters in the Local Group

Mackey, A. D.; Beasley, M. A.; Leaman, R.
Referencia bibliográfica

Monthly Notices of the Royal Astronomical Society: Letters, Volume 460, Issue 1, p.L114-L118

Fecha de publicación:
7
2016
Número de autores
3
Número de autores del IAC
1
Número de citas
9
Número de citas referidas
8
Descripción
We present Gemini Multi-Object Spectrograph (GMOS) imaging of 12 candidate intergalactic globular clusters (IGCs) in the Local Group, identified in a recent survey of the Sloan Digital Sky Survey (SDSS) footprint by di Tullio Zinn & Zinn. Our image quality is sufficiently high, at ˜0.4-0.7 arcsec, that we are able to unambiguously classify all 12 targets as distant galaxies. To reinforce this conclusion we use GMOS images of globular clusters in the M31 halo, taken under very similar conditions, to show that any genuine clusters in the putative IGC sample would be straightforward to distinguish. Based on the stated sensitivity of the di Tullio Zinn & Zinn search algorithm, we conclude that there cannot be a significant number of IGCs with MV ≤ -6 lying unseen in the SDSS area if their properties mirror those of globular clusters in the outskirts of M31 - even a population of 4 would have only a ≈1 per cent chance of non-detection.