J/A+A/701/A23 GCs in Field 1 of the Centaurus cluster (Federle+, 2025)
A song of interactions and mergers: The case of NGC 4709.
Federle S., Gomez M., Mieske S., Dux F., Hilker M., Yegorova I.A.
<Astron. Astrophys. 701, A23 (2025)>
=2025A&A...701A..23F 2025A&A...701A..23F (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Galaxies, nearby ; Clusters, globular ;
Photometry, SDSS
Keywords: globular clusters: general - galaxies: individual: NGC 4709 -
galaxies: star clusters: general
Abstract:
Globular clusters (GCs) are fundamental tools to unveil the
interaction and merger history of their host galaxies.
Our goal is to perform the photometric analysis of the globular
cluster system (GCS) of the elliptical galaxy NGC 4709, which is the
brightest galaxy of the Cen 45 spiral-rich galaxy group, and to
highlight its interaction history with NGC 4696, the giant elliptical
galaxy of the Cen 30 subcluster.
We obtained deep Magellan 6.5m/MegaCam (g', r', i') photometry, with
which we identified a sample of 556 GC candidates around NGC 4709 that
were analyzed in the context of the interaction history with the giant
elliptical NGC 4696 and other galaxies of the Cen 45 group. After
modeling and subtracting the galaxy light, we used criteria based on
shape, colors and magnitude to select GC candidates.
Our results point toward a complex interaction history that shaped the
GCS of NGC 4709. Inside a galactocentric radius r<5reff, two
populations were found with mean colors of (g'-i')_0=0.905±0.009mag
and (g'-i')_0=1.170±0.008mag. The azimuthal distribution of the GCs
show peaks at the position angles PA1=92° and PA2=293°,
with PA2 coinciding with the direction toward NGC 4696, confirming
that the interaction between these galaxies shaped the GCS of
NGC 4709. From the GC luminosity function we derived a distance of
29.9±2.1Mpc, which is much closer than the other galaxies of the
Centaurus cluster, and a specific frequency of SN=3.7±0.5, in good
agreement with previously estimated values. From the GCs density maps,
we identified overdensities corresponding to the positions of other
five galaxies of the Centaurus cluster, and we found a bridge of GCs
between NGC 4709 and NGC 4696 with a distance of d=34.69±2.21Mpc,
which is between that of the two galaxies.
All these findings point toward a complex GCS for NGC 4709, strongly
influenced by the interaction with NGC 4696, and confirm previous
findings that the galaxy's apparent distance is smaller than that of
the main cluster galaxy NGC 4696 by ∼8.5Mpc and it is smaller than the
distance of the other Centaurus' galaxies, making it an outlier in
Centaurus and suggesting a past first encounter with Cen 30. In future
work, we will combine our data with E-MOSAICS simulations to unravel
NGC 4709 trajectory, from the past interaction to the future new
rendezvous with NGC 4696.
Description:
The photometric data for this publication were obtained with
Magellan/MegaCam in the g', r', and i' filters. We observed the
∼26.91x26.40arcmin2 corresponding to Field 1 of the Centaurus
cluster, covering the elliptical galaxy NGC 4709 with the aim to
characterize its globular cluster system, and to determine the
properties of the GCs in Field 1 of the Centaurus cluster.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 157 5199 Properties of the globular cluster candidates
in Field 1 of the Centaurus cluster
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See also:
J/A+AS/124/1 : The Centaurus Cluster Catalogue (Jerjen+ 1997)
J/AJ/132/347 : Redshifts & photometry in Centaurus cluster (Chiboucas+, 2006)
J/ApJS/170/95 : Centaurus Cluster catalog (Chiboucas+, 2007)
J/A+A/496/683 : Early-type galaxies in the Centaurus cluster (Misgeld+, 2009)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Right Ascension (J2000)
4- 5 I2 min RAm Right Ascension (J2000)
7- 11 F5.2 s RAs Right Ascension (J2000)
13 A1 --- DE- Declination sign (J2000)
15- 16 I2 deg DEd Declination (J2000)
18- 19 I2 arcmin DEm Declination (J2000)
21- 25 F5.2 arcsec DEs Declination (J2000)
27- 31 F5.3 --- CLASSgp Stellarity index in g' band
33- 37 F5.3 --- CLASSrp Stellarity index in r' band
39- 43 F5.3 --- CLASSip Stellarity index in i' band
45- 50 F6.3 mag gp0mag Extinction corrected magnitude in the
g' band (AB) (1)
52- 56 F5.3 mag e_gp0mag Error on g'0 magnitude
58- 63 F6.3 mag rp0mag Extinction corrected magnitude in the
r' band (AB) (1)
65- 69 F5.3 mag e_rp0mag Error on r'0 magnitude
71- 76 F6.3 mag ip0mag Extinction corrected magnitude in the
i' band (AB) (1)
78- 82 F5.3 mag e_ip0mag Error on i'0 magnitude
84- 89 F6.3 arcmin rNGC4709 Distance from NGC 4709 center
91- 96 F6.3 arcmin rNGC4706 Distance from NGC 4706 center
98-103 F6.3 arcmin rNGC4696 Distance from NGC 4696 center
105-110 F6.3 arcmin rWISEA Distance from WISEA J124956.33-411536.8
center
112-117 F6.3 arcmin rESO323 Distance from ESO 323-G 009 center
119-125 F7.3 deg PANGC4709 Position angle relative to NGC 4709
127-133 F7.3 deg PANGC4706 Position angle relative to NGC 4706
135-141 F7.3 deg PANGC4696 Position angle relative to NGC 4696
143-149 F7.3 deg PAWISEA Position angle relative to
WISEA J124956.33-411536.8
151-157 F7.3 deg PAESO323 Position angle relative to ESO 323-G 009
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Note (1): The adopted absorption corrections are taken from Schlafly &
Finkbeiner (2011ApJ...737...103S).
The magnitudes in our work are in the AB system.
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Acknowledgements:
Sara Federle, sara.federle89(at)gmail.com
(End) Patricia Vannier [CDS] 21-Jul-2025