J/ApJ/943/153 High-z protocluster candidates from COSMOS2020 (Brinch+, 2023)
COSMOS2020: identification of high-z protocluster candidates in COSMOS.
Brinch M., Greve T.R., Weaver J.R., Brammer G., Ilbert O., Shuntov M.,
Jin S., Liu D., Gimenez-Arteaga C., Casey C.M., Davidson I., Fujimoto S.,
Koekemoer A.M., Kokorev V., Magdis G., McCracken H.J., McPartland C.J.R.,
Mobasher B., Sanders D.B., Toft S., Valentino F., Zamorani G., Zavala J.,
(The COSMOS Team)
<Astrophys. J., 943, 153 (2023)>
=2023ApJ...943..153B 2023ApJ...943..153B
ADC_Keywords: Clusters, galaxy; Photometry; Optical; Redshifts;
Photometry, infrared
Keywords: High-redshift galaxy clusters ; Galaxy evolution ;
Large-scale structure of the universe
Abstract:
We conduct a systematic search for protocluster candidates at z≥6 in
the Cosmic Evolution Survey (COSMOS) field using the recently released
COSMOS2020 source catalog. We select galaxies using a number of
selection criteria to obtain a sample of galaxies that have a high
probability of being inside a given redshift bin. We then apply
overdensity analysis to the bins using two density estimators, a
Weighted Adaptive Kernel estimator and a Weighted Voronoi Tessellation
estimator. We have found 15 significant (>4σ) candidate galaxy
overdensities across the redshift range 6≤z≤7.7. The majority of the
galaxies appear to be on the galaxy main sequence at their respective
epochs. We use multiple stellar-mass-to-halo-mass conversion methods
to obtain a range of dark matter halo mass estimates for the
overdensities in the range of ∼1011-1013M☉, at the
respective redshifts of the overdensities. The number and the masses
of the halos associated with our protocluster candidates are
consistent with what is expected from the area of a COSMOS-like survey
in a standard Λ cold dark matter cosmology. Through comparison
with simulation, we expect that all of the overdensities at z∼6 will
evolve into Virgo-/Coma-like clusters at present (i.e., with masses
∼1014-1015M☉). Compared to other overdensities identified at
z≥6 via narrowband selection techniques, the overdensities presented
appear to have ∼10x higher stellar masses and star formation rates
(SFRs). We compare the evolution in the total SFR and stellar mass
content of the protocluster candidates across the redshift range
6≤z≤7.7 and find agreement with the total average SFR from
simulations.
Description:
The COSMOS survey covers 2deg2 and boasts a plethora of deep
multiwavelength data in over 40 bands from the world's major
facilities (Scoville+ 2007ApJS..172....1S 2007ApJS..172....1S). The new version of the
COSMOS source catalog, COSMOS2020 (Weaver+ 2022, J/ApJS/258/11),
constitutes a major improvement over the previous catalog
(Laigle+ 2016, J/ApJS/224/24), in that it includes detections and new
ultra-deep optical/NIR imaging and multiwave band photometry of
1.7 million sources over the entire COSMOS field, with ∼89000 measured
in all of the available broadband filters. Key additions for
COSMOS2020 include new ultra-deep optical data from the Hyper
Suprime-Cam Subaru Strategic Program (HSC-SSP) public data release 2
(PDR2; Aihara+ 2019PASJ...71..114A 2019PASJ...71..114A), new data from the Visible
Infrared Survey Telescope for Astronomy (VISTA) data release 4 (DR4;
McCracken+ 2012, J/A+A/544/A156), reaching up to one magnitude deeper
over the full area than previous data, and the inclusion of all
Spitzer IRAC data in COSMOS (Moneti+ 2022A&A...658A.126E 2022A&A...658A.126E). Legacy data
sets (such as the Suprime-Cam imaging) have also been reprocessed (see
Weaver et al. 2022 for details).
Photometric redshifts and physical parameters, including stellar
masses and SFRs, for the COSMOS2020 sources, were derived using two
independent photometric redshift codes, LePhare
(Arnouts+ 2002MNRAS.329..355A 2002MNRAS.329..355A; Ilbert+ 2006A&A...457..841I 2006A&A...457..841I) and
EAZY (Brammer+ 2008ApJ...686.1503B 2008ApJ...686.1503B). See Section 2.2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 87 15 Properties of the overdensities found at z=6-10
table3.dat 108 15 *Estimates of the total dark matter halo mass
associated with the protocluster candidate
(see Section 4.3)
galaxies.dat 106 107 Properties of the individual galaxies in the
15 overdensities found at z=6-10 from
LePhare and EAZY (Tables 4-18;
see also Figures 18-32)
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Note on table3.dat: Estimates of the total dark matter halo mass associated
with the protocluster candidate at the redshift of the overdensity and
the most massive individual halo at the redshift of the overdensity
using Behroozi+ (2013ApJ...770...57B 2013ApJ...770...57B),
Behroozi & Silk (2018MNRAS.477.5382B 2018MNRAS.477.5382B), and Shuntov+ (2022A&A...664A..61S 2022A&A...664A..61S)
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See also:
II/373 : The fourth UltraVISTA data release (DR4) (Moneti+, 2019)
J/ApJS/176/301 : Subaru/XMM-Newton deep survey IV. (SXDS) (Ouchi+, 2008)
J/MNRAS/416/2041 : Hα emitters at z=2.23 (Matsuda+, 2011)
J/A+A/544/A156 : UltraVISTA Catalogue Release DR1 (McCracken+, 2012)
J/A+A/559/A2 : z in the surroundings of MRC 0156-252 (Galametz+, 2013)
J/ApJS/206/8 : COSMOS/UltraVISTA Ks-selected catalogs v4.1 (Muzzin+, 2013)
J/ApJ/805/121 : Overdensities of 0<z<3 COSMOS galaxies (Darvish+, 2015)
J/ApJ/819/62 : The COSMOS-Legacy Survey (CLS) catalog (Civano+, 2016)
J/MNRAS/460/3861 : Herschel protocluster survey (Kato+, 2016)
J/ApJS/224/24 : The COSMOS2015 catalog (Laigle+, 2016)
J/ApJ/826/114 : z∼3-6 protocl. in the CFHTLS deep fields (Toshikawa+, 2016)
J/MNRAS/478/3740 : High-z LAEs and LBGs in SHARDS survey (Arrabal Haro+, 2018)
J/ApJ/862/96 : Dusty star-forming galaxies with LABOCA obs. (Lewis+, 2018)
J/PASJ/70/S10 : GOLDRUSH I. UV magnitudes (Ono+, 2018)
J/ApJS/243/22 : CANDELS/SHARDS catalog in GOODS-N (Barro+, 2019)
J/ApJ/890/7 : Environment of gal. in the 5 CANDELS fields (Chartab+, 2020)
J/MNRAS/508/3754 : Study of nine SPT protocluster candidates (Wang+, 2021)
J/ApJS/258/11 : The COSMOS2020 catalog (Weaver+, 2022)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Overdensity name (PCzN.NN-NN)
12- 13 I2 --- Ngin [5/19] Number of galaxies inside the 4σ
overdensity contour
15- 16 I2 --- Nlbg [0/13] Number of galaxies classified as LBGs
18- 21 F4.2 --- zmean [6/7.7] Mean redshift of overdensity members
23- 24 I2 h RAh Hour of right ascension (J2000) (1)
26- 27 I2 min RAm Minute of right ascension (J2000)
29- 33 F5.2 s RAs Second of right ascension (J2000)
35 A1 --- DE- Sign of declination (J2000) (1)
36- 37 I2 deg DEd Degree of declination (J2000) (1)
39- 40 I2 arcmin DEm Arcminute of declination (J2000)
42- 46 F5.2 arcsec DEs Arcsecond of declination (J2000)
48- 51 F4.1 --- delta [4.7/13] Peak overdensity value inside the
4σ contour, δmax
53- 55 F3.1 --- e_delta [1.9/4] Lower uncertainty on delta (2)
57- 59 F3.1 --- E_delta [2.2/5] Upper uncertainty on delta (2)
61- 65 F5.2 [Msun] logMs [9.6/11.1] Total stellar mass of all
overdensity members
67- 70 F4.2 [Msun] e_logMs [0.09/0.32] Lower uncertainty on logMs
72- 75 F4.2 [Msun] E_logMs [0.08/0.3] Upper uncertainty on logMs
77- 79 I3 Msun/yr SFR [37/692] Total UV SFR of all overdensity members
81- 83 I3 Msun/yr e_SFR [5/162] Lower uncertainty on SFR
85- 87 I3 Msun/yr E_SFR [5/234] Upper uncertainty on SFR
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Note (1): R.A. and decl. of the peak overdensity value inside the 4σ
contour.
Note (2): With the upper lower 1σ (corresponding to Gaussian statistics
1σ=0.8413) Poisson uncertainties (Gehrels 1986ApJ...303..336G 1986ApJ...303..336G).
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Overdensity name (PCzN.NN-NN)
12 A1 --- l_logMdmB Limit flag on logMdmB
13- 17 F5.2 --- logMdmB log of total dark matter halo mass using
Behroozi+ 2013ApJ...770...57B 2013ApJ...770...57B
19- 22 F4.2 --- e_logMdmB [0.09/0.32] Lower uncertainty on logMdmB
24- 27 F4.2 --- E_logMdmB [0.08/0.3] Upper uncertainty on logMdmB
29- 33 F5.2 --- AbundB [11.54/12.9]? Abundance matching
(see Behroozi+ 2013ApJ...770...57B 2013ApJ...770...57B)
35- 38 F4.2 --- e_AbundB [0.07/0.4]? Lower uncertainty on AbundB
40- 43 F4.2 --- E_AbundB [0.07/0.6]? Upper uncertainty on AbundB
45 A1 --- l_logMdmC Limit flag on logMdmC
46- 50 F5.2 --- logMdmC Central dark matter halo mass estimates
52- 55 F4.2 --- e_logMdmC [0.05/0.35] Lower uncertainty on logMdmC
57- 60 F4.2 --- E_logMdmC [0.06/0.32] Upper uncertainty on logMdmC
62- 66 F5.2 --- AbundC [11/12.53]? Abundance matching
68- 71 F4.2 --- e_AbundC [0.09/0.5]? Lower uncertainty on AbundC
73- 76 F4.2 --- E_AbundC [0.07/0.7]? Upper uncertainty on AbundC
78- 82 F5.2 --- logMdmS [11.89/12.53] log of total dark matter halo
mass using Shuntov+ (2022A&A...664A..61S 2022A&A...664A..61S)
halo occupation distribution-based (HOD)
model
84- 87 F4.2 --- e_logMdmS [0.05/0.1] Lower uncertainty on logMdmS
89- 92 F4.2 --- E_logMdmS [0.05/0.11] Upper uncertainty on logMdmS
94- 98 F5.2 --- logMdmH [11.8/12.3] log of central dark matter halo
mass HOD model
100- 103 F4.2 --- e_logMdmH [0.02/0.3] Lower uncertainty on logMdmH
105- 108 F4.2 --- E_logMdmH [0.02/0.3] Upper uncertainty on logMdmH
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Byte-by-byte Description of file: galaxies.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Overdensity name; column added by CDS
12- 13 I2 --- Seq [1/19] Running sequence number within Name
14 A1 --- f_Seq [*] Flag on Seq (1)
16- 21 I6 --- ID [12090/958367] Identifier in COSMOS2020,
"Farmer" catalog (Weaver+ 2022, J/ApJS/258/11)
23- 24 I2 h RAh [9/10] Hour of right ascension (J2000)
26- 27 I2 min RAm Minute of right ascension (J2000)
29- 33 F5.2 s RAs Second of right ascension (J2000)
35 A1 --- DE- [+] Sign of declination (J2000)
36- 37 I2 deg DEd [1/2] Degree of declination (J2000)
39- 40 I2 arcmin DEm Arcminute of declination (J2000)
42- 46 F5.2 arcsec DEs Arcsecond of declination (J2000)
48- 51 F4.2 --- zLP [5.96/7.8] LePhare redshift
53- 56 F4.2 --- e_zLP [0.04/6.6] Lower uncertainty on zLP
58- 61 F4.2 --- E_zLP [0.03/1.7] Upper uncertainty on zLP
63- 66 F4.2 --- zEazy [5.7/7.7] EAZY redshift
68- 71 F4.2 --- e_zEazy [0.01/7.2] Lower uncertainty on zEazy
73- 76 F4.2 --- E_zEazy [0.01/5] Upper uncertainty on zEazy
78- 81 F4.1 [Msun] logMs [8.2/10.6] log of stellar mass; LePhare
83- 85 F3.1 [Msun] e_logMs [0/0.4] Lower uncertainty on logMs
87- 89 F3.1 [Msun] E_logMs [0.1/0.4] Upper uncertainty on logMs
91- 93 I3 Msun/yr SFR [1/286] UV star formation rate
95- 96 I2 Msun/yr e_SFR [1/80] Lower uncertainty on SFR
98-100 I3 Msun/yr E_SFR [1/114] Upper uncertainty on SFR
102-106 F5.2 mag Ksmag [24/31.5]? Ks-band AB magnitude
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Note (1): Code as follows:
* = galaxies are i-dropouts according to the criteria in
Ono+ (2017, J/PASJ/70/S10).
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Nomenclature note:
Sources in the COSMOS field from Weaver+ 2022, J/ApJS/258/11; "Farmer"
catalog are <COSMOS2020 Farmer NNNNNN> in Simbad.
History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 10-Jan-2025