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 !!!