J/MNRAS/450/1962 M60 SLUGGS and Gemini/GMOS combined study (Pota+, 2015)
A SLUGGS and Gemini/GMOS combined study of the elliptical galaxy M60:
wide-field photometry and kinematics of the globular cluster system.
Pota V., Brodie J.P., Bridges T., Strader J., Romanowsky A.J., Villaume A.,
Jennings Z., Faifer F.R., Pastorello N., Forbes D.A., Campbell A.,
Usher C., Foster C., Spitler L.R., Caldwell N., Forte J.C., Norris M.A.,
Zepf S.E., Beasley M.A., Gebhardt K., Hanes D.A., Sharples R.M.,
Arnold J.A.
<Mon. Not. R. Astron. Soc., 450, 1962-1983 (2015)>
=2015MNRAS.450.1962P 2015MNRAS.450.1962P (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Clusters, globular ; Radial velocities ;
Photometry
Keywords: galaxies: formation - galaxies: haloes -
galaxies: kinematics and dynamics -
galaxies: star clusters: individual: NGC 4649
Abstract:
We present new wide-field photometry and spectroscopy of the globular
clusters (GCs) around NGC 4649 (M60), the third brightest galaxy in
the Virgo cluster. Imaging of NGC 4649 was assembled from a recently
obtained Hubble Space Telescope/Advanced Camera for Surveys
mosaic, and new Subaru/Suprime-Cam and archival Canada-France-Hawaii
Telescope/MegaCam data. About 1200 sources were followed up
spectroscopically using combined observations from three multi-object
spectrographs: Keck/Deep Imaging Multi-Object Spectrograph,
Gemini/Gemini Multi-Object Spectrograph and Multiple Mirror
Telescope/Hectospec. We confirm 431 unique GCs belonging to NGC 4649,
a factor of 3.5 larger than previous data sets and with a factor of 3
improvement in velocity precision. We confirm significant GC colour
bimodality and find that the red GCs are more centrally concentrated,
while the blue GCs are more spatially extended. We infer negative GC
colour gradients in the innermost 20kpc and flat gradients out to
large radii. Rotation is detected along the galaxy major axis for all
tracers: blue GCs, red GCs, galaxy stars and planetary nebulae. We
compare the observed properties of NGC 4649 with galaxy formation
models. We find that formation via a major merger between two gas-poor
galaxies, followed by satellite accretion, can consistently reproduce
the observations of NGC 4649 at different radii. We find no strong
evidence to support an interaction between NGC 4649 and the
neighbouring spiral galaxy NGC 4647. We identify interesting GC
kinematic features in our data, such as counter-rotating subgroups and
bumpy kinematic profiles, which encode more clues about the formation
history of NGC 4649.
Description:
Our imaging comes from three sources: HST/ACS, CFHT/MegaCam and
Subaru/Suprime-Cam.
We use SExtractor (Bertin & Arnouts, 1996A&AS..117..393B 1996A&AS..117..393B) to extract
sources from the Suprime-Cam and MegaCam images.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 58 431 Catalogue of the 431 spectroscopically
confirmed GCs associated with NGC 4649
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See also:
J/MNRAS/355/608 : NGC 4649 (M60) globular clusters (Forbes+, 2004)
J/ApJ/760/87 : Globular clusters of M60 with HST (Strader+, 2012)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID Sequential number, this paper
5- 8 A4 --- [SFL2012] ID from Strader et al. (2012, J/ApJ/760/87),
if available, [SFL2012] ANNN in Simbad
10- 20 F11.7 deg RAdeg Right ascension (J2000)
22- 31 F10.7 deg DEdeg Declination (J2000)
33- 37 F5.3 mag g-z Reddening corrected g-z colour (1)
39- 44 F6.3 mag zmag Reddening corrected magnitude in the z-band (1)
46- 49 I4 arcsec R Circularized galactocentric radius
51- 54 I4 km/s RV Observed radial velocity
56- 58 I3 km/s e_RV Radial velocity error (2)
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Note (1): either from Strader et al. (2012, J/ApJ/760/87), or
converted from gri magnitudes as described in Section 4.2.
Note (2): renormalized to the DEIMOS uncertainties (see text).
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 10-Dec-2015