J/AJ/169/263 S-PLUS photometry of Fornax cl. GC candidates (Lomeli-Nunez+, 2025)
The S-PLUS Fornax Project (S+FP): Mapping globular clusters systems within 5
virial radii around NGC 1399.
Lomeli-Nunez L., Cortesi A., Smith Castelli A.V., Buzzo M.L., Mayya Y.D.,
Fragkou V., Alzate-Trujillo J.A., Haack R.F., Calderon J.P., Lopes A.R.,
Hilker M., Grossi M., Menendez-Delmestre K., Goncalves T.S.,
Chies-Santos A.L., Gutierrez-Soto L.A., Lima-Dias C., Werner S.V.,
Humire P.K., Thom de Souza R.C., Alvarez-Candal A., Panda S.,
Chaturvedi A., Telles E., Mendes de Oliveira C., Kanaan A., Ribeiro T.,
Schoenell W.
<Astron. J., 169, 263 (2025)>
=2025AJ....169..263L 2025AJ....169..263L
ADC_Keywords: Clusters, globular; Clusters, galaxy; Photometry; Optical; Colors
Keywords: Globular star clusters ; Galaxy clusters ; Surveys ;
Galaxy formation ; Galaxy evolution
Abstract:
We present the largest sample (∼13,000 candidates, ∼3000 of which are
bona fide candidates) of globular cluster (GCs) candidates reported in
the Fornax cluster so far. The survey is centered on the NGC 1399
galaxy, extending out to 5 virial radii (Rvir) of the cluster. We
carried out a photometric study using images observed in the 12-band
system of the Southern Photometric Local Universe Survey (S-PLUS),
corresponding to 106 pointings, covering a sky area of ∼208 square
degrees. Studying the properties of spectroscopically confirmed GCs,
we have designed a method to select GC candidates using structural and
photometric parameters. We found evidence of color bimodality in two
broadband colors, namely (g-i)0 and (g-z)0, while, in the narrow
bands, we did not find strong statistical evidence to confirm
bimodality in any color. We analyzed the GCs luminosity functions
(GCLF) in the 12 bands of S-PLUS, and we can highlight two points: (a)
due to the relatively shallow depth of S-PLUS, it is only possible to
observe the bright end of the GCLF and, (b) at that level, in all of
the bands, it can be considered to be the log-normal distribution
typical for GC systems. With the spatial coverage reached in this
study, we are able, for the first time, to explore the large-scale
distribution of GCs within and around a galaxy cluster. In particular,
we noted that the GCs might be clustered along substructures, which
trace the current cluster buildup.
Description:
The Southern Photometric Local Universe Survey (S-PLUS) will cover
∼9300 square degrees of the sky. S-PLUS DR4 (II/380) includes
observations taken between August 2016 and February 2021. It uses a
robotic ∼0.8m telescope that is located at the Cerro Tololo
Inter-American Observatory (CTIO) in Chile. It uses the Javalambre
12-filter photometric system designed for the Javalambre-Photometric
Local Universe Survey (Cenarro+, 2019A&A...622A.176C 2019A&A...622A.176C). The filter
system is composed of the following seven narrowband filters:
J0378 (3771Å), J0395 (3941Å), J0410 (4094Å), J0430 (4292Å),
J0515 (5133Å), J0660 (6614Å), and J0861 (8611Å).
These map the [OII], Ca H+K, Hδ, G-band, Mgb triplet, and
Hα and Ca triplet lines, respectively. The system also includes
the u (3577Å), g (4774Å), r (6275Å), i (7702Å), and
z (8882Å) broadband filters (similar to SDSS).
The S-PLUS Fornax cluster data are part of the Main Survey (MS) of
S-PLUS and cover an FOV of ∼20x12 square degrees in 106 pointings
with the 12 bands, which made it possible to detect ∼3 million sources.
For the selection of new GC candidates in the 106 Fornax pointings of
S-PLUS, we used SExtractor-derived structural and classifier
parameters to define an initial cluster sample. This sample has been
refined using color-magnitude and color-color diagrams. In addition,
we make use of Gaia DR3 (I/355) to reject Galactic objects, and
finally we estimated the redshift (z) of the remaining objects
applying spectral energy distribution (SED) fitting techniques in
order to reject background sources.
Objects:
------------------------------------------------------------
RA (2000) DE Designation(s)
------------------------------------------------------------
03 38 29.08 -35 27 02.6 NGC 1399 = 1H 0335-357
03 38 29.40 -35 27 07.9 Fornax cluster = ACO S 373
------------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table4.dat 126 12999 Broad band colors and observational properties of
the GC candidates in the Fornax galaxy cluster
--------------------------------------------------------------------------------
See also:
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
II/380 : S-PLUS DR4 photometrical catalog (Herpich+, 2024)
VII/202 : Globular Clusters in the Milky Way (Harris, 1997)
J/A+AS/133/325 : Velocities of 12 Fornax elliptical galaxies (Graham+ 1998)
J/PASP/110/863 : A Stellar Spectral Flux Library: 1150 - 25000 A (Pickles 1998)
J/A+A/404/223 : 2MASS IR star clusters in the Galaxy (Bica+, 2003)
J/ApJS/153/223 : ACS Virgo Cluster Survey. I. (Cote+, 2004)
J/MNRAS/367/156 : C-T1 photometry in NGC 1374, 1379 and 1387 (Bassino+, 2006)
J/A+A/464/L21 : Velocities of globular clusters in Fornax (Bergond+, 2007)
J/ApJS/169/213 : ACS Fornax Cluster Survey. I. (Jordan+, 2007)
J/ApJS/171/101 : Globular clusters in ACS Virgo clust. surv. (Jordan+, 2007)
J/AJ/135/1567 : Bright star clusters in M51 (Hwang+, 2008)
J/ApJ/679/404 : Star clusters in M82 (Mayya+, 2008)
J/ApJ/681/197 : ACS Virgo Cluster Survey. XV (Peng+, 2008)
J/A+A/477/L9 : Globular clusters around NGC 1399 (Schuberth+, 2008)
J/MNRAS/402/803 : M31 globular cluster system (Peacock+, 2010)
J/A+A/513/A52 : Velocities of NGC 1399 globular clusters (Schuberth+, 2010)
J/MNRAS/417/1823 : Sombrero galaxy globular clusters (Alves-Brito+, 2011)
J/MNRAS/417/L6 : Cat. of stellar cluster properties in M83 (Bastian+, 2011)
J/ApJ/746/88 : HST observations of GCs in NGC 1399 (Blakeslee+, 2012)
J/ApJ/772/82 : A catalog of globular cluster systems (Harris+, 2013)
J/ApJ/763/40 : UBVI phot. of GCs in the Fornax galaxy cluster (Kim+, 2013)
J/MNRAS/428/389 : SLUGGS globular clust. in early-type galaxies (Pota+, 2013)
J/ApJS/221/13 : ACS Fornax Cluster Survey. XI. GC candidates (Jordan+, 2015)
J/ApJ/813/L15 : Dwarf galaxies in Fornax cluster from NGFS (Munoz+, 2015)
J/ApJ/805/160 : Old star clusters in M101 from HST (Simanton+, 2015)
J/ApJ/802/30 : NGVS VI. Ultra-compact dwarfs in M87 (Zhang+, 2015)
J/ApJ/835/184 : Glob. clust. candidates in NGC4258 (Gonzalez-Lopezlira+, 2017)
J/A+A/611/A93 : NGC3115 & NGC1399 VEGAS-SSS globular clust. (Cantiello+, 2018)
J/ApJ/855/142 : Next Generation Fornax Survey (NGFS) II. (Eigenthaler+, 2018)
J/ApJ/860/4 : NGFS. IV. The Fornax core region (Ordenes-Briceno+, 2018)
J/MNRAS/490/1666 : Spectroscopic census of the Fornax cluster (Maddox+, 2019)
J/A+A/623/A65 : Multiphot. of M31 outer halo globular clusters (Wang+, 2019)
J/ApJ/899/140 : 632 Gaia Ultracompact Dwarf galaxy candidates (Voggel+, 2020)
J/A+A/657/A93 : Fornax globular clusters (Chaturvedi+, 2022)
J/ApJ/941/53 : GC syst. & SMBHs in spiral gal. III. (Gonzalez-Lopezlira+, 2022)
J/MNRAS/509/180 : GC in 5 nearby spiral galaxies (Lomeli-Nunez+, 2022)
J/ApJS/267/27 : SMUDGes V. The complete cat. of UDGs from DR9 (Zaritsky+, 2023)
J/A+A/691/A138 : S-PLUS Ultra-Short Survey DR1 (Perottoni+, 2024)
J/A+A/693/A306 : SPLUS DR4 VAC - Predicted Parameters (Ferriera Lopes+, 2025)
J/A+A/695/A104 : Hα-excess S-PLUS Catalogs (Gutierrez-Soto+, 2025)
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 21 A21 --- Name Assigned name of bona fide globular cluster
candidate (1)
23- 30 F8.5 deg RAdeg Right ascension (J2000)
32- 40 F9.5 deg DEdeg Declination (J2000)
42- 46 F5.2 mag imag [19/22] PSF i-band Vega magnitude [mag_psf]
48- 51 F4.2 mag e_imag [0.02/0.19] Uncertainty in imag
53- 57 F5.2 mag (u-i)0 [-1.45/79.93] (u-i) dereddened color
59- 63 F5.2 mag e_(u-i)0 [0.07/99] Uncertainty in (u_i)0 (2)
65- 69 F5.2 mag (g-r)0 [-0.33/1.58] (g-r) dereddened color
71- 74 F4.2 mag e_(g-r)0 [0.04/0.27] Uncertainty in (g_r)0 (2)
76- 79 F4.2 mag (g-i)0 [0.6/2.44] (g-i) dereddened color
81- 84 F4.2 mag e_(g-i)0 [0.04/0.27] Uncertainty in (g_i)0 (2)
86- 89 F4.2 mag (g-z)0 [0.17/2.96] (g-z) dereddened color
91- 94 F4.2 mag e_(g-z)0 [0.05/0.28] Uncertainty in (g_z)0 (2)
96- 99 F4.2 pix FWHM [2.8/9.99] S-extractor compactness classifier
(3)
101- 104 F4.2 --- Class [0.2/0.9] S-extractor stellarity structural
classifier; compact sources ∼ 1 [class_star]
106- 111 F6.3 --- Spread [-0.02/0.02] Another stellarity S-extractor
classifier; compact sources ∼ 0 [spread_model]
113- 117 F5.3 --- FluxRad [0.62/8.17] Effective aperture radius,
S-extractor parameter [flux_radius] (4)
119- 124 F6.2 mag iMag [-12.4/-9.5] Absolute i-band magnitude
126 I1 --- flag [0/2] S-extractor flag classification (5)
--------------------------------------------------------------------------------
Note (1): Assigned name, which follows the convention of FGC_field_n, where
F is for Fornax and GC for globular cluster, field corresponds to the name
of the pointing in which the GC candidate is located, and n is 1 for the
brightest object in the i-band, and increases sequentially as the magnitude
increases. the "F" in FGC does not appear in the table.
Note (2): Error is the quadrature sum of the error in each band from SExtractor
Note (3): At the distance of Fornax the pixel scale is 50.6pc/pixel (with
Fornax parameters: 19Mpc, m-M=31.51; Blakeslee+, 2009ApJ...694..556B 2009ApJ...694..556B).
Note (4): This is the radius of the circle centered on the light barycenter
that encloses half of the total flux.
Note (5): Flag classification as follows:
0 = clusters without u-band photometry (8135 occurrences)
1 = determined as a reddened young cluster from u-band photometry
(2211 occurrences)
2 = determined as BF-GCC from u-band photometry (2653 occurrences)
3 = error in (u-i) is likely to be larger than the indicated formal error
(0 occurrence)
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Robin Leichtnam [CDS] 23-Jan-2026