2017MNRAS.469.3444T -
Mon. Not. R. Astron. Soc., 469, 3444-3467 (2017/August-2)
The Survey of Centaurus A's Baryonic Structures (SCABS) - II. The extended globular cluster system of NGC 5128 and its nearby environment.
TAYLOR M.A., PUZIA T.H., MUNOZ R.P., MIESKE S., LANCON A., ZHANG H., EIGENTHALER P. and BOVILL M.S.
Abstract (from CDS):
New wide-field ugriz Dark Energy Camera observations centred on the nearby giant elliptical galaxy NGC 5128 covering ∼21 deg2 are used to compile a new catalogue of ∼3200 globular clusters (GCs). We report 2404 newly identified candidates, including the vast majority within ∼140 kpc of NGC 5128. We find evidence for a transition at a galactocentric radius of Rgc ≃ 55 kpc from GCs 'intrinsic' to NGC 5128 to those likely to have been accreted from dwarf galaxies or that may transition to the intragroup medium of the Centaurus A galaxy group. We fit power-law surface number density profiles of the form Σ_N, R_ gc_∝R_ gc_^Γand find that inside the transition radius, the red GCs are more centrally concentrated than the blue, with Γ_inner, red_ ≃ -1.78 and Γ_inner, blue_ ≃ -1.40, respectively. Outside this region both profiles flatten, more dramatically for the red GCs (Γ_outer, red_ ≃ -0.33) compared to the blue (Γ_outer, blue_ ≃ -0.61), although the former is more likely to suffer contamination by background sources. The median (g - z)0 = 1.27 mag colour of the inner red population is consistent with arising from the amalgamation of two giant galaxies each less luminous than present-day NGC 5128. Both inwards and outwards of the transition radius, we find the fraction of blue GCs to dominate over the red GCs, indicating a lively history of minor mergers. Assuming the blue GCs to originate primarily in dwarf galaxies, we model the population required to explain them, while remaining consistent with NGC 5128's present-day spheroid luminosity. We find that several dozen dwarfs of luminosities L_dw, V_ ≃ 106–9.3 L_V, ☉_, following a Schechter luminosity function with a faint-end slope of -1.50 <= α <= -1.25 is favoured, many of which may have already been disrupted in NGC 5128's tidal field.
Abstract Copyright:
© 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society
Journal keyword(s):
galaxies: elliptical and lenticular, cD - galaxies: formation - galaxies: individual: NGC 5128 - galaxies: star clusters: general - galaxies: star clusters: general
VizieR on-line data:
<Available at CDS (J/MNRAS/469/3444): table2.dat table3.dat table4.dat table5.dat>
Status at CDS
:
Examining the need for a new acronym. // All or part of tables of objects could be ingested in SIMBAD with priority 2.
Simbad objects:
7
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