2011ApJ...736L..26A


Query : 2011ApJ...736L..26A

2011ApJ...736L..26A - Astrophys. J., 736, L26 (2011/August-1)

The fossil record of two-phase galaxy assembly: kinematics and metallicities in the nearest S0 galaxy.

ARNOLD J.A., ROMANOWSKY A.J., BRODIE J.P., CHOMIUK L., SPITLER L.R., STRADER J., BENSON A.J. and FORBES D.A.

Abstract (from CDS):

We present a global analysis of kinematics and metallicity in the nearest S0 galaxy, NGC 3115, along with implications for its assembly history. The data include high-quality wide-field imaging from Suprime-Cam on the Subaru telescope, and multi-slit spectra of the field stars and globular clusters (GCs) obtained using Keck-DEIMOS/LRIS and Magellan-IMACS. Within two effective radii, the bulge (as traced by the stars and metal-rich GCs) is flattened and rotates rapidly (v/σ ≳ 1.5). At larger radii, the rotation declines dramatically to v/σ ∼ 0.7, but remains well aligned with the inner regions. The radial decrease in characteristic metallicity of both the metal-rich and metal-poor GC subpopulations produces strong gradients with power-law slopes of -0.17±0.04 and -0.38±0.06 dex/dex, respectively. We argue that this pattern is not naturally explained by a binary major merger, but instead by a two-phase assembly process where the inner regions have formed in an early violent, dissipative phase, followed by the protracted growth of the outer parts via minor mergers with typical mass ratios of ∼15-20:1.

Abstract Copyright:

Journal keyword(s): galaxies: bulges - galaxies: formation - galaxies: halos - galaxies: individual: NGC 3115 - galaxies: kinematics and dynamics - globular clusters: general

Simbad objects: 8

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Number of rows : 8
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 NGC 821 G 02 08 21.150 +10 59 41.53   12.210 11.310 10.739 9.744 ~ 546 0
2 NGC 3115 GiG 10 05 13.978 -07 43 06.89   11   9.37   ~ 951 2
3 NAME NGC 3115 DW1 GiG 10 05 41.5916956639 -07 58 53.592496977   14.32 13.45     ~ 78 1
4 NGC 3377 GiP 10 47 42.400 +13 59 08.30 11.55 11.24 10.38     ~ 736 1
5 NGC 4125 GiP 12 08 06.017 +65 10 26.88 11.14 10.65 9.72     ~ 402 2
6 NGC 4697 GiG 12 48 35.8992791099 -05 48 02.497675635   10.97   9.83   ~ 818 0
7 NAME Centaurus A Sy2 13 25 27.61509104 -43 01 08.8056025   8.18 6.84 6.66   ~ 4123 3
8 NAME Local Group GrG ~ ~           ~ 7360 0

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2021.09.27-17:44:17

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