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The extremely populated globular cluster
system of the lenticular galaxy NGC 6861
Lic. Carlos G. EscuderoDr. Favio R. FaiferDra. Lilia P. BassinoDr. Juan Pablo CalderónDr. Juan Pablo Caso
Toronto 2015 – Future & Science of Gemini ObservatoryEscudero et al. (2015)
Machacek et al. (2010)
Filters g', r', i' 0.43 - 0.88 arcsec
4x700 sec
4x350 sec
4x400 sec
Galaxy surface proile and tidal structures
Galaxy surface proile and tidal structures
External arcs
Difuse surface
brightness
Galaxy surface proile and tidal structures
Globular cluster colours
Globular cluster colours
Colour histograms
Blom et al. (2012)
View poster Escudero et al.
Colour histograms
(g'-i')0 0.88≤ 0.88<(g'-i')0<1.01 (g'-i')0 1.01≥
Colour histograms
Spatial distribution
Azimuthal properties
Blue tilt
Faifer et al. (2011)
Wehner et al. (2008)
Escudero et al. (2015)
Blue tilt
Comparison with the hot gas emission
Forte et al. (2005)
Forbes et al. (2012)
Comparison with the hot gas emission
Forte et al. (2005)
Forbes et al. (2012)
Machacek et al. (2010)
Comparison with the hot gas emission
Forte et al. (2005)
Forbes et al. (2012)
Machacek et al. (2010)
Total number of GCs and speciic frequency
Ntot: 3000 ± 300 GCs
SN = 9.2 ± 2.2 !!!
SN = NCG 100.4(Mv+15)
Total number of GCs and speciic frequency
Ntot: 3000 ± 300 GCs
SN = 9.2 ± 2.2 !!!
SN = NCG 100.4(Mv+15)
Mhalo~10¹³ M☉
Harris et al. 2015
Flamingos-2
SUMMARY
* NGC 6861 presents signs of past interaction or merger
* The galaxy has a large GC system. By examining the colour histograms and the
CMD, we inferred the possible existence of a third subpopulation with intermediate
colours. However, spectroscopic and/or IR data are needed to perform an age-
metallicity study.
* The presence of a blue-tilt is detected in the blue subpopulation
* Outside 10 kpc, the blue subpopulation shows a remarkable similarity between the
projected density proile and the X-ray surface brightness proile of the galaxy. This
result would indicate that NGC 6861 could be the dominant galaxy in a galaxy sub-
group.
* We have estimated a total population of 3000±300 GCs for NGC 6861
* We obtained a high speciic frequency of SN=9.2±2.2. This high SN value could be
interpreted as a sign of the presence of a massive halo in NGC 6861.
Gracias !!!