J/A+A/609/A78 MUSE combined data cubes for NGC 3311 (Barbosa+, 2018)
Sloshing in its cD halo:
MUSE kinematics of the central galaxy NGC 3311 in the Hydra I cluster.
Barbosa C.E., Arnaboldi A., Coccato L., Gerhard O., Mendes de Oliveira C.,
Hilker M., Richtler T.
<Astron. Astrophys. 609, A78 (2018)>
=2018A&A...609A..78B 2018A&A...609A..78B (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, optical
Keywords: galaxies: clusters: individual: Hydra I -
galaxies: individual: NGC 3311 -
galaxies: elliptical and lenticular, cD -
galaxies: kinematics and dynamics - galaxies: structure -
galaxies: stellar content
Abstract:
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.
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
sigma, and small (constant) values of the higher order Gauss-Hermite
moments h3 and h4.
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 Vσ with simulated galaxies indicates
that NGC 3311 assembled mainly through dry mergers. The sigma profile
rises to approximately 400$ km/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 h_4
values within 10 kpc.
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.
Description:
Combined MUSE data cubes for four fields of NGC 3311. Original data is
available at the ESO archive, identified by the program ID
094.B-0711(A). All relevant technical data are included in the FITS
header of the data cube. The flux units are in [ergs/s/cm2/Angstrom].
Objects:
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RA (2000) DE Designation(s)
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10 36 42.82 -27 31 42.0 NGC 3311 = ESO 501-38
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 177 4 List of fits datacubes
fits/* . 4 Individual datacubes
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See also:
J/A+A/589/A139 : Stellar populations of NGC 3311 (Barbosa+, 2016)
Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 22 F3.1 arcsec/pix scale Scale of the image
24- 26 I3 --- Nx Number of pixels along X-axis
28- 30 I3 --- Ny Number of pixels along Y-axis
32- 35 I4 --- Nz Number of slices
37- 59 A23 --- Obs.date Observation date (YYYY-MM-DDThh:mm:ss.ss)
61- 67 F7.2 0.1nm blambda Lower value of wavelength interval
69- 75 F7.2 0.1nm Blambda Upper value of wavelength interval
77- 80 F4.2 0.1nm dlambda Wavelength resolution
82- 88 I7 Kibyte size Size of FITS file
90-152 A63 --- FileName Name of FITS file, in subdirectory fits
154-177 A24 --- Title Title of the FITS file
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Acknowledgements:
Carlos E. Barbosa, carlos.barbosa(at)usp.bt
(End) Carlos E. Barbosa [USP-IAG], Patricia Vannier [CDS] 09-Nov-2017