J/A+A/661/A4 eFEDS optical cluster and group catalog (Klein+, 2022)
The eROSITA Final Equatorial-Depth Survey (eFEDS).
Optical confirmation, redshifts, and properties of the cluster and
group catalog.
Klein M., Oguri M., Mohr J.J., Grandis S., Ghirardini V., Liu T., Liu A.,
Bulbul E., Wolf J., Comparat J., Ramos-Ceja M.E., Buchner J., Chiu I.,
Clerc N., Merloni A., Miyatake H., Miyazaki S., Okabe N., Ota N.,
Pacaud F., Salvato M., Driver S.P.
<Astron. Astrophys. 661, A4 (2022)>
=2022A&A...661A...4K 2022A&A...661A...4K (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Redshifts ; X-ray sources ; Surveys
Keywords: catalogs - galaxies: clusters: general -
galaxies: distances and redshifts -
galaxies: clusters: intracluster medium - X-rays: galaxies: clusters
Abstract:
In 2019, the eROSITA telescope on board of the Russian-German
satellite Spectrum-Roentgen-Gamma (SRG), has started to perform a deep
all-sky X-ray survey with the aim of identifying ∼100000 clusters and
groups over the course of four years. As part of its performance
verification phase a ∼140deg2 survey called eROSITA Final
Equatorial-Depth Survey (eFEDS) was performed. With a depth typical of
the all-sky survey after four years, it allows tests of tools and
methods as well as improved predictions for the all-sky survey.
As part of this effort, a catalog of 542 X-ray extent selected galaxy
group and cluster candidates was constructed. In this paper we present
the optical follow-up with the aim of providing redshifts and cluster
confirmation for the full sample. Further we aim to provide additional
information on cluster dynamical state, cluster richness and cluster
optical center. Finally we aim to evaluate the impact of optical
cluster confirmation on the purity and completeness of the X-ray
selected sample.
We use optical imaging data from the Hyper Suprime-Cam Subaru
Strategic Program and from the Legacy Survey to identify optical
counterparts to the X-ray detected cluster candidates. We make use of
the red sequence based cluster redshift and confirmation tool MCMF as
well as the optical cluster finder CAMIRA to derive cluster redshifts
and richnesses. MCMF provided probabilities of an optical structure
being a chance super position with the X-ray candidate is used to
identify the best optical counter part as well as to confirm an X-ray
candidate as a cluster. The impact of this confirmation process on
catalog purity and completeness is estimated using optical to X-ray
scaling relations as well as simulations. The resulting catalog is
further matched with public group and cluster catalogs. Optical
estimators of cluster dynamical state are constructed based on density
maps of the red sequence galaxies at the cluster redshift.
While providing redshift estimates for all 542 candidates, we
construct an optically confirmed sample of 477 clusters and groups
with a residual contamination of 6%. Of these, 470 (98.5%) are
confirmed using MCMF, and 7 systems are added through cross matching
with spectroscopic group catalogs. Using observable to observable
scaling and the applied confirmation threshold, we predict 8±2 real
systems have been excluded with the MCMF cut required to build this
low contamination sample. This number is in good agreement with the 7
systems found through cross matching that were not confirmed with
MCMF. The predicted redshift and mass distribution of this catalog is
in good agreement with simulations. Thus, we expect those 477 systems
to include >99% of all true clusters in the candidate list. Using an
MCMF independent method, we confirm the catalog contamination of the
confirmed subsample to be 6±3%. Applying the same method to the
full candidate list yields 17±3%, consistent with estimates coming
from the fraction of confirmed systems of ∼17% and expectations from
simulations of ∼20%. We further present a sample of merging cluster
candidates based on the derived estimators of cluster dynamical state.
Description:
This table contains the main results on the optical confirmation of
eROSITA eFEDS sources using MCMF (*_COMB), Bytes 197-538. It further
contains MCMF results of the individual MCMF runs using Legacy Survey
(*_LS, Bytes 540-760) and HSC-SSP (*_HSC, Bytes 762-968). Entries
till byte 195 are taken from the original eSASS based X-ray catalog
(see Brunner et al., 2022A&A...661A...1B 2022A&A...661A...1B, Cat. J/A+A/661/A1).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 968 542 Cluster catalog with MCMF entries
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See also:
J/MNRAS/474/3324 : Multicomponent matched filter test (Klein+, 2018)
J/MNRAS/488/739 : MARD-Y3 catalog (Klein+, 2019)
J/A+A/661/A1 : The eFEDS X-ray catalogs (V7.4) (Brunner+, 2022)
J/A+A/661/A2 : Galaxy clusters and groups in eFEDS (Liu+, 2022)
J/A+A/661/A3 : eFEDS counterparts to point-like sources (Salvato+, 2022)
J/A+A/661/A5 : The eFEDS AGN catalog (Liu+, 2022)
J/A+A/661/A7 : X-ray properties of eFEDS clusters and groups (Bahar+, 2022)
J/A+A/661/A8 : eFEDS catalogue of variable X-ray sources (Boller+, 2022)
J/A+A/661/A10 : eFEDS galaxy clusters and groups in disguise (Bulbul+, 2022)
J/A+A/661/A23 : Exoplanet X-ray irradiation & evaporation rates (Foster+, 2022)
J/A+A/661/A24 : Corona-chromosphere connection (Fuhrmeister+, 2022)
J/A+A/661/A29 : First eROSITA study of nearby M dwarfs (Magaudda+, 2022)
J/A+A/661/A34 : eta Cha cluster eROSITA X-ray scan (Robrade+, 2022)
J/A+A/661/A35 : eROSITA study of 47 Tuc globular cluster (Saeedi+, 2022)
J/A+A/661/A38 : SRG/ART-XC 1st year all-sky X-ray survey (Pavlinsky+, 2022)
J/A+A/661/A40 : eRASS1 X-ray sources Sco-Cen members (Schmitt+, 2022)
J/A+A/661/A44 : A first eROSITA view of ultracool dwarfs (Stelzer+, 2022)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 22 A22 --- Name eROSITA source name (NAME)
24- 28 I5 --- ID-SRC Source ID of detection pipeline
(ID_SRC)
30- 38 F9.5 deg RAdeg Right ascension of the X-ray
center (J2000) (RA_CORR)
40- 48 F9.5 deg DEdeg Declination of the X-ray
center (J2000) (DEC_CORR)
50- 58 F9.6 arcsec ePos Positional uncertainty
(RADECERRCORR)
60- 67 F8.5 arcsec Ext Source extent in X-ray (EXT)
69- 80 F12.5 arcsec e_Ext [] Error in source extent (EXT_ERR)
82- 90 F9.5 --- ExtLike Extent likelihood (EXT_LIKE)
92-101 F10.5 ct MLCT Source counts (ML_CTS)
103-114 E12.6 ct e_MLCT [] Error on counts (MLCTSERR)
116-123 F8.6 ct/s MLRate Count rate (ML_RATE)
125-136 F12.6 ct/s e_MLRate [] Error on count rate (MLRATEERR)
138-149 E12.6 --- MLFlux Source flux (ML_FLUX)
151-162 E12.6 --- e_MLFlux Error on flux (MLFLUXERR)
164-173 F10.5 --- DetLike Detection likelihood (DET_LIKE)
175-182 F8.5 --- MLBkg Background (ML_BKG)
184-193 F10.5 --- MLExpTime Exposure time (ML_EXP)
195 A1 --- INAREA90 [FT] Label for column 18 (INAREA90)
197-205 F9.6 --- FcontBest fcont of best optical counter part:
-1, -2 for manually added systems
(FCONTBEST_COMB)
207-212 F6.4 --- zBest Photometric redshift of best
counter part (ZBESTCOMB)
214-220 F7.4 --- e_zBest ?=- Uncertainty of the photometric
redshift (SIGMAZBEST_COMB)
222-228 F7.3 --- lambdaBest Richness of best counter part
(LAMBDABESTCOMB)
230-236 F7.4 --- e_lambdaBest [] Uncertainty richness
(ELAMBDABESTCOMB)
238-239 I2 --- SurvBest [-1/2] Survey used
(SURVBESTCOMB) (1)
241-249 F9.5 deg RAOdeg Right ascension of optical center of
best counter part (J2000)
(RAOPTCENBEST_COMB)
251-259 F9.5 deg DEOdeg Declination of optical center of
best counter part (J2000)
(DECOPTCENBEST_COMB)
261-268 F8.5 --- zspBest Spectrscopic redshift
(SPECZBEST_COMB)
270-271 I2 --- o_zspBest Number of redshifts used for spec-z
(N_SPEC)
273-280 F8.6 --- MProxBest Approx. M500 used for richness
estimate [1/h] (MASSPROXBESTCOMB)
282-290 F9.6 --- Fcont2Best Second best f_cont of best optical
counter part: -1, -2 for manually
added systems (FCONT2BEST_COMB)
292-300 F9.6 --- z2Best Second Photometric redshift of best
counter part (Z2BESTCOMB)
302-308 F7.4 --- lambda2Best Second Richness of best
counter part (LAMBDA2BESTCOMB)
310-316 F7.4 --- e_lambda2Best Second Uncertainty richness
(ELAMBDA2BESTCOMB)
318-324 F7.4 --- e_z2Best Second Uncertainty of the
photometric redshift
(SIGMAZ2BEST_COMB)
326 I1 --- Surv2Best [0/2] Second Survey used
(SURV2BESTCOMB) (1)
328-339 E12.6 --- MProx2Best Second bApprox. M500 used for
richness estimate [1/h]
(MASSPROX2BESTCOMB)
341 I1 --- FlagO-Xpos Value of the optical footprint map
at X-ray position
(FLAGOPTICALX_POS)
343-350 F8.6 --- MaskFr3Foot Fraction of the area not in the
optical footprint within a 3 arcmin
radius (MASKFRAC3FOOT)
352-359 F8.6 --- MaskFrFlg Fraction of the area not in the
optical footprint within a 3 arcmin
radius but including flagged area
due to bright star masks
(MASKFRAC3FLAGGED)
361-368 F8.6 --- MaskFrR500Foot Fraction of the area not in the
optical footprint within a 3 arcmin
radius but for a r_500 sized region
(MASKFRACR500FOOTBESTCOMB)
370-377 F8.6 --- MaskFrR500Flg Fraction of the area not in the
optical footprint within a 3 arcmin
radius but for a r_500 sized region
(MASKFRACR500FLAGGEDBESTCOMB)
379-386 F8.6 --- MaskFrR500Foot2 Fraction of the area not in the
optical footprint within a 3 arcmin
radius for 2nd best counter part
(MASKFRACR500FOOT2BESTCOMB)
388-395 F8.6 --- MaskFrR500Flg2 Fraction of the area not in the
optical footprint within a 3 arcmin
radius but including flagged area
due to bright star masks but for
2nd best counter part
(MASKFRACR500FLAGGED2BESTCOMB)
397-405 F9.5 deg RAGdeg Right ascension of galaxy density
map based centre (J2000)
(RAGDMAPBEST_COMB)
407-415 F9.5 deg DEGdeg Declination of galaxy density map
based centre (J2000)
(DECGDMAPBEST_COMB)
417-425 F9.5 deg RAG2deg Right ascension of galaxy density
map based centre for 2nd best
counterpart (J2000)
(RAGDMAP2BEST_COMB)
427-435 F9.5 deg DEG2deg Declination of galaxy density map
based centre for 2nd best
counterpart (J2000)
(DECGDMAP2BEST_COMB)
437-445 F9.5 deg RABdeg Right ascension of best BCG
candidate (J2000)
(RABCGBEST_COMB)
447-455 F9.5 deg DEBdeg Declination of best BCG candidate
(J2000) (DECBCGBEST_COMB)
457-465 F9.7 --- alpha ?=- Dynamical state estimator alpha
(ALPHA)
467-475 F9.7 --- delta ?=- Dynamical state estimator delta
(DELTA)
477-485 F9.7 --- beta ?=- Dynamical state estimator beta
(BETA)
487-494 F8.6 --- ellip ?=- Dynamical state estimator:
model ellipticity (ELLIP)
496-503 F8.6 --- CenterShift ?=- Shift of the centre of the 2D
density model with respect to X-ray
position (CENTERSHIFT)
505-513 F9.6 --- DistNOR500 ?=- Distance to next optical
structure in the galaxy density map
(DISTNEXTOPT_R500)
515-524 F10.6 Mpc DistNX ?=- Distance to next extent
selected eFEDS cluster in MPC
(DISTNEXTXCLUSTMPC)
526-535 F10.6 --- DistNXR500 ?=- Distance to next extent selected
eFEDS cluster
(DISTNEXTXCLUSTR500)
537-538 A2 --- MCMFNwaySec [12ABCD ] Sector in f_cont- p_any
plane according to Sect. 5.4
(MCMFNWAYSECTOR)
540-549 F10.6 --- FcontLFCLS fcont of best optical counter part
of individual MCMF run using legacy
survey (FCONTLFC_LS)
551-559 F9.5 --- zLFCLS Corresponding redshift (ZLFCLS)
561-570 F10.6 --- lambdaLFCLS Corresponding richness
(LAMBDALFCLS)
572-581 F10.6 --- e_lambdaLFCLS [] Uncertainty of the richness
(ELAMBDALFCLS)
583-591 F9.5 --- zP1LS Redshift of first peak in lambda
versus redshift plot (ZP1LS)
593-601 F9.5 --- zP2LS Redshift of second peak in lambda
versus redshift plot (ZP2LS)
603-611 F9.5 --- zP3LS Redshift of third peak in lambda
versus redshift plot (ZP3LS)
613-622 F10.6 --- lambdaP1LS Richness of first peak
(LAMBDAP1LS)
624-633 F10.6 --- lambdaP2LS Richness of second peak
(LAMBDAP2LS)
635-644 F10.6 --- lambdaP3LS Richness of third peak
(LAMBDAP3LS)
646-655 F10.6 --- e_lambdaP1LS [] Uncertainty on the richness of
first peak (ELAMBDAP1LS)
657-666 F10.6 --- e_lambdaP2LS [] Uncertainty on the richness of
second peak (ELAMBDAP2LS)
668-677 F10.6 --- e_lambdaP3LS [] Uncertainty on the richness of
third peak (ELAMBDAP3LS)
679-688 F10.6 --- FcontP1LS fcont of the first peak
(FCONTP1_LS)
690-699 F10.6 --- FcontP2LS fcont of the second peak
(FCONTP2_LS)
701-708 F8.6 --- FcontP3LS fcont of the third peak
(FCONTP3_LS)
710-720 F11.7 --- DeltaLFCLS Difference in f_cont between best
and 2nd best counter part
(DELTALFCLS)
722-730 F9.6 --- e_zLFCLS ?=- Uncertainty of the photometric
redshift (SIGMAZLFC_LS)
732-740 F9.6 --- e_zP1LS ?=- Uncertainty of the photometric
redshift of the 1st peak
(SIGMAZP1_LS)
742-750 F9.6 --- e_zP2LS ?=- Uncertainty of the photometric
redshift of the 2nd peak
(SIGMAZP2_LS)
752-760 F9.6 --- e_zP3LS ?=- Uncertainty of the photometric
redshift of the 3rd peak
(SIGMAZP3_LS)
762-769 F8.6 --- FcontLFCHSC f_cont of best optical counter part
of individual MCMF run using
HSC-SSP (HSC) (FCONTLFC_HSC)
771-780 F10.6 --- zLFCHSC Corresponding redshift of best
counter part in HSC (ZLFCHSC)
782-792 F11.6 --- lambdaLFCHSC Richness of first peak
(LAMBDALFCHSC)
794-803 F10.6 --- e_lambdaLFCHSC [] Uncertainty on the richness of
first peak (ELAMBDALFCHSC)
805-813 F9.6 --- e_zLFCHSC ?=- Uncertainty of the photometric
redshift (SIGMAZLFC_HSC)
815-824 F10.6 --- zP1HSC Redshift of first peak in lambda
versus redshift plot (ZP1HSC)
826-835 F10.6 --- zP2HSC Redshift of second peak in lambda
versus redshift plot (ZP2HSC)
837-846 F10.6 --- zP3HSC Redshift of third peak in lambda
versus redshift plot (ZP3HSC)
848-858 F11.6 --- lambdaP1HSC Richness of first peak
(LAMBDAP1HSC)
860-869 F10.6 --- lambdaP2HSC Richness of second peak
(LAMBDAP2HSC)
871-879 F9.5 --- lambdaP3HSC Richness of third peak
(LAMBDAP3HSC)
881-890 F10.6 --- e_lambdaP1HSC [] Uncertainty on the richness of
first peak corresponding
(ELAMBDAP1HSC)
892-901 F10.6 --- e_lambdaP2HSC [] Uncertainty on the richness of
second peak corresponding
(ELAMBDAP2HSC)
903-911 F9.5 --- e_lambdaP3HSC [] Uncertainty on the richness of
third peak corresponding
(ELAMBDAP3HSC)
913-921 F9.6 --- e_zP1HSC ?=- Uncertainty of the photometric
redshift of the 1st peak
(SIGMAZP1_HSC)
923-931 F9.6 --- e_zP2HSC ?=- Uncertainty of the photometric
redshift of the 2nd peak
(SIGMAZP2_HSC)
933-941 F9.6 --- e_zP3HSC Uncertainty of the photometric
redshift of the 3rd peak
(SIGMAZP3_HSC)
943-950 F8.6 --- FcontP1HSC fcont of the first peak
(FCONTP1_HSC)
952-959 F8.6 --- FcontP2HSC fcont of the second peak
(FCONTP2_HSC)
961-968 F8.6 --- FcontP3HSC fcont of the third peak
(FCONTP3_HSC)
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Note (1): Survey used as follows :
-1 = group catalog
1 = LS
2 = HSC
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Acknowledgements:
Matthias Klein, matthias.klein(at)physik.lmu.de
References:
The Early Data Release of eROSITA and Mikhail Pavlinsky ART-XC on the
SRG mission, 2022, A&A, 661, A1-A46
(End) Patricia Vannier [CDS] 06-Aug-2021