J/A+A/700/A30 N2CLS COSMOS field NIKA2 galaxy cluster cand. (Cherouvrier+, 2025)
NIKA2 Cosmological Legacy Survey.
Blind detection of galaxy clusters in the COSMOS field via the SZ effect.
Cherouvrier D., Macias-Perez J.F., Desert F.X., Adam R., Ade P., Ajeddig H.,
Amarantidis S., Andre P., Aussel H., Barrena R., Beelen A., Benoit A.,
Berta S., Bethermin M., Bongiovanni A., Bounmy J., Bourrion O., Bing L.-J.,
Calvo M., Catalano A., De Petris M., Doyle S., Driessen E.F.C., Ejlali G.,
Ferragamo A., Fernandez-Torreiro M., Gomez A., Goupy J., Hanser C.,
Katsioli S., Keruzore F., Kramer C., Ladjelate B., Lagache G., Leclercq S.,
Lestrade J.-F., Madden S.C., Maury A., Mayet F., Melin J.-B., Monfardini A.,
Moyer-Anin A., Munoz-Echeverria M., Myserlis I., Neri R., Paliwal A.,
Perotto L., Pisano G., Pointecouteau E., Ponthieu N., Pratt G.W.,
Reveret V., Rigby A.J., Ritacco A., Roussel H., Ruppin F.,
Sanchez-Portal M., Savorgnano S., Schuster K., Sievers A., Tucker C.,
Zylka R.
<Astron. Astrophys. 700, A30 (2025)>
=2025A&A...700A..30C 2025A&A...700A..30C (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Redshifts ; Millimetric/submm sources ; Surveys
Keywords: galaxies: clusters: general - cosmology: observations -
large-scale structure of Universe
Abstract:
Clusters of galaxies, formed in the latest stages of structure
formation, are unique cosmological probes. With the advent of large
CMB surveys like those from the Planck satellite, the ACT and SPT
telescopes, we now have access to a large number of galaxy clusters
detected at millimeter wavelengths via the thermal Sunyaev-Zel'dovich
(tSZ) effect. Nevertheless, it is interesting to complement them with
high angular resolution (tens of arcseconds) observations to target
the lowest mass and highest redshift clusters. This is the case of
observations with the NIKA2 camera, which is installed on the IRAM
30-m telescope in Pico Veleta, Spain. We use here the existing 150GHz
(2mm) data from the NIKA2 Cosmological Legacy Survey (N2CLS) Large
Program to blindly search for galaxy clusters in the well-known COSMOS
field, across a 877 arcmin2 region centered on
(R.A., Dec.)J2000=(10:00:28.81,+02:17:30.44). We first develop a
dedicated data reduction pipeline to construct NIKA2 maps at 2mm. We
then use a matched-filter algorithm to extract cluster candidates
assuming a universal pressure profile to model the expected cluster
tSZ signal. We compute the purity and completeness of the sample by
applying the previous algorithm to simulated maps of the sky signal in
the COSMOS field, including tSZ contribution, point sources and
instrumental noise. We find a total of 16 cluster candidates at S/N>4,
from which 8 have either an optical or X-ray cluster (or group of
galaxies) counterpart. This is the first blind detection of clusters
of galaxies at mm wavelengths at 18arcsec angular resolution. For
candidates with available redshift estimates, we derive their mass by
modeling the cluster tSZ signal with a universal pressure profile via
a MCMC analysis. From this analysis, we confirm that NIKA2 and the
IRAM 30-m telescope should be sensitive to low mass clusters at
intermediate and high redshift, complementing current and planned
large tSZ-based cluster surveys.
Description:
We present the NIKA2 galaxy cluster candidate catalog, detected via
the SZ effect in the COSMOS field, using data from the NIKA2
Cosmological Legacy Survey (N2CLS). This dataset includes a total of
195 hours of observations of the COSMOS field.
The cosmology used throughout this paper follows the ΛCDM
cosmology from Planck Col.+ (2020A&A...641A...6P 2020A&A...641A...6P) with ωm=0.31
and H0= 67.7km/s/Mpc. All masses are expressed using the quantity
M500, which represents the mass contained within a radius R500, where
the average density equals 500 times the critical density at the
cluster redshift.
The N2CLS final maps and catalogs are available online on the
survey's home page: https://data.lam.fr/n2cls/home.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 144 16 Cluster candidates catalog
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 25 A25 --- Name Cluster name, NK2-CL JHHMMSS.s+DDMMSS.s
27- 34 F8.4 deg RAdeg Right ascension (J2000)
36- 41 F6.4 deg DEdeg Declination (J2000)
43- 46 F4.2 --- SNR Signal-to-noise ratio of the detection
48- 51 F4.2 --- z ?=- Estimated redshift of the candidate
52 A1 --- f_z [*] Note on z (1)
54- 57 F4.2 --- e_z ?=- z uncertainty
58 A1 --- n_z (p) photometric or (s) spectroscopic
redshift
60- 63 F4.2 arcmin theta500 Estimated cluster angular size theta500
65- 68 F4.2 arcmin e_theta500 Lower 68% confidence limit of theta500
70- 73 F4.2 arcmin E_theta500 Upper 68% confidence limit of theta500
75- 79 F5.2 10-5arcmin+2 Y500 Estimated tSZ flux Y500
81- 85 F5.2 10-5arcmin+2 e_Y500 Lower 68% confidence limit of Y500
87- 91 F5.2 10-5arcmin+2 E_Y500 Upper 68% confidence limit of Y500
93- 96 F4.2 10+14Msun M500 ?=- Estimated cluster mass M500
98-101 F4.2 10+14Msun e_M500 ?=- Lower 68% confidence limit of M500
103-106 F4.2 10+14Msun E_M500 ?=- Upper 68% confidence limit of M500
108-132 A25 --- MatchCl Name of the matched counterpart in
external catalogs
133 A1 --- n_MatchCl [*] Note on MatchCl (2)
135-138 F4.1 arcsec MatcDist ?=- Distance of the counterpart to the
NIKA2 cluster candidate center
140-144 A5 --- Refs ? Reference(s) for the counterpart (3)
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Note (1): NK2-CL J100011.9+021256.5: possible superposition of a low and a high
redshift cluster.
Note (2): A * indicates that the object is a group of galaxies.
Note (3): Reference as follows:
1 = Ascaso et al. 2015MNRAS.452..549A 2015MNRAS.452..549A, J/MNRAS/452/549
2 = Bellagamba et al. 2011MNRAS.413.1145B 2011MNRAS.413.1145B, J/MNRAS/413/1145
3 = Knobel et al. 2009ApJ...697.1842K 2009ApJ...697.1842K, J/ApJ/697/1842
4 = Iovino et al. 2016A&A...592A..78I 2016A&A...592A..78I
5 = Sochting et al. 2012MNRAS.423.2436S 2012MNRAS.423.2436S, J/MNRAS/423/2436
6 = Mehrtens et al. 2012MNRAS.423.1024M 2012MNRAS.423.1024M, J/MNRAS/423/1024
7 = Zou et al. 2021ApJS..253...56Z 2021ApJS..253...56Z, J/ApJS/253/56
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Acknowledgements:
Damien Cherouvrier, cherouvrier(at)lpsc.in2p3.fr
(End) Patricia Vannier [CDS] 24-Jul-2025