2018A&A...609A..78B


Query : 2018A&A...609A..78B

2018A&A...609A..78B - Astronomy and Astrophysics, volume 609A, 78-78 (2018/1-1)

Sloshing in its cD halo: MUSE kinematics of the central galaxy NGC 3311 in the Hydra I cluster.

BARBOSA C.E., ARNABOLDI M., COCCATO L., GERHARD O., MENDES DE OLIVEIRA C., HILKER M. and RICHTLER T.

Abstract (from CDS):

Context. Early-type galaxies (ETGs) show a strong size evolution with redshift. This evolution is explained by fast "in-situ" star formation at high-z followed by a late mass assembly mostly driven by minor mergers that deposit stars primarily in the outer halo.
Aims. We aim to identify the main structural components of the Hydra I cD galaxy NGC 3311 to investigate the connection between the central galaxy and the surrounding stellar halo.
Methods. We produce maps of the line-of-sight velocity distribution (LOSVD) moments from a mosaic of MUSE pointings covering NGC 3311 out to 25kpc. Combining deep photometric and spectroscopic data, we model the LOSVD maps using a finite mixture distribution, including four non-concentric components that are nearly isothermal spheroids, with different line-of-sight systemic velocities V, velocity dispersions σ, and small (constant) values of the higher order Gauss-Hermite moments h3 and h4.
Results. The kinemetry analysis indicates that NGC 3311 is classified as a slow rotator, although the galaxy shows a line-of-sight velocity gradient along the photometric major axis. The comparison of the correlations between h3 and h4 with V/σ with simulated galaxies indicates that NGC 3311 assembled mainly through dry mergers. The σ profile rises to ~=400km/s at 20kpc, a significant fraction (0.55) of the Hydra I cluster velocity dispersion, indicating that stars there were stripped from progenitors orbiting in the cluster core. The finite mixture distribution modeling supports three inner components related to the central galaxy and a fourth component with large effective radius (51kpc) and velocity dispersion (327km/s) consistent with a cD envelope. We find that the cD envelope is offset from the center of NGC 3311 both spatially (8.6kpc) and in velocity (ΔV=204km/s), but coincides with the cluster core X-ray isophotes and the mean velocity of core galaxies. Also, the envelope contributes to the broad wings of the LOSVD measured by large h4 values within 10kpc.
Conclusions. The cD envelope of NGC 3311 is dynamically associated with the cluster core, which in Hydra I is in addition displaced from the cluster center, presumably due to a recent subcluster merger.

Abstract Copyright: © ESO, 2018

Journal keyword(s): galaxies: clusters: individual: Hydra I - galaxies: individual: NGC 3311 - galaxies: elliptical and lenticular, cD - galaxies: kinematics and dynamics - galaxies: structure - galaxies: stellar content

VizieR on-line data: <Available at CDS (J/A+A/609/A78): list.dat fits/*>

Simbad objects: 14

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Number of rows : 14
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 NAME HYA SUPERCL SCG 08 57.9 +03 10           ~ 164 0
2 NGC 3309 GiG 10 36 35.6607096792 -27 31 05.732321664   11.98 11.78 10.34 10.51 ~ 154 0
3 NAME Hydra I Cluster ClG 10 36 36.0 -27 31 04           ~ 808 1
4 2MASX J10364122-2733392 GiG 10 36 41.1952357848 -27 33 39.785933952   15.7 14.18   12.99 ~ 41 0
5 NGC 3311 BiC 10 36 42.821 -27 31 42.02   11.93 10.93 10.00 9.67 ~ 286 2
6 GALEX J103645.9-273126 GiC 10 36 45.85 -27 31 24.2     17.87   16.94 ~ 13 0
7 M 87 BiC 12 30 49.42338230 +12 23 28.0438581 10.16 9.59 8.63   7.49 ~ 6734 3
8 NGC 4874 LIN 12 59 35.7093764280 +27 57 33.293892204 13.01 13.7 11.40 12.122 11.386 ~ 758 3
9 ACO 1656 ClG 12 59 48.7 +27 58 50           ~ 4548 2
10 ZwCl 1358+6245 ClG 13 59 54.3 +62 30 36     18.5     ~ 354 0
11 IC 1101 rG 15 10 56.100 +05 44 41.19   15.10       ~ 152 2
12 ACO 2199 ClG 16 28 37.0 +39 31 28           ~ 1132 1
13 3C 338.0 QSO 16 28 38.2446374616 +39 33 04.235250060   12.78 11.78     ~ 731 5
14 NGC 7507 GiG 23 12 07.595 -28 32 22.70   11.60   9.98   ~ 171 0

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2022.09.24-17:47:25

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