2023A&A...673A..92B

Query : 2023A&A...673A..92B

2023A&A...673A..92B - Astronomy and Astrophysics, volume 673A92 (2023/5-1)

The XXL Survey L. Active galactic nucleus contamination in galaxy clusters: Detection and cosmological impact.

BHARGAVA S., GARREL C., KOULOURIDIS E., PIERRE M., VALTCHANOV I., CERARDI N., MAUGHAN B.J., AGUENA M., BENOIST C., BAGULEY C., RAMOS-CEJA M.E., ADAMI C., CHIAPPETTI L., VIGNALI C. and WILLIS J.P.

Abstract (from CDS):

Context. X-ray observations of galaxy clusters are impacted by the presence of active galactic nuclei (AGNs) in a manner that is challenging to quantify, leading to biases in the detection and measurement of cluster properties for both astrophysics and cosmological applications.
Aims. We detect and characterise clusters contaminated by central AGNs within the XXL survey footprint and provide a systematic assessment of the cosmological impact of such systems in X-ray cluster samples.
Methods. We introduce a new automated class for AGN-contaminated (AC) clusters in the XXL source detection pipeline. The majority of these systems are otherwise missed by current X-ray cluster-detection methods. The AC selection is also effective in distinguishing AGN and cool-core presence using supplementary optical and infrared information.
Results. We present 33 AC objects, including 25 clusters in the redshift range, 0.14 ≤ z ≤ 1.03, and eight other sources with significantly peaked central profiles based on X-ray observations. Six of these are new confirmed clusters. We computed the missed fraction of the XXL survey, which is defined as the fraction of genuine clusters that are undetected due to their centrally peaked X-ray profiles. We report seven undetected AC clusters above z > 0.6, in the range where X-ray cluster detection efficiency drops significantly. The missed fraction is estimated to be at the level of 5% for the 50 square-degree XXL area. The impact on cosmological estimates from missed clusters is negligible for XXL, but it produces a tension of ∼3σ with the fiducial cosmology when considering larger survey areas.
Conclusions. This work demonstrates the first systematic attempt to quantify the percentage of missed clusters in X-ray surveys as a result of central AGN contamination. Looking towards surveys such as eROSITA and Athena, larger areas and increased sensitivity will significantly enhance cluster detection, and therefore robust methods for characterising AGN contamination will be crucial for precise cluster cosmology, particularly in the redshift z > 1 regime.

Abstract Copyright: © The Authors 2023

Journal keyword(s): X-rays: galaxies: clusters - cosmological parameters - galaxies: active - surveys - large-scale structure of Universe - galaxies: clusters: general

Simbad objects: 36

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Number of rows : 36
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 MCG-01-06-033 AGN 02 02 18.3321144552 -06 59 59.219125584   16   14.59   ~ 8 0
2 XLSSU J020435.7-061922 C?G 02 04 36 -06 19.4           ~ 1 0
3 XLSSU J020514.7-045638 ClG 02 05 14.70 -04 56 40.0           ~ 2 0
4 MCG-01-06-042 AGN 02 05 19.6987188480 -06 27 02.965514112   13.57 13.10     ~ 29 0
5 XLSSC 095 ClG 02 07 51 -05 12.4           ~ 11 0
6 QSO J0208-0503 QSO 02 08 03.0342249552 -05 03 00.039588048     18.75     ~ 19 0
7 XLSSC 115 ClG 02 10 43 -06 35.3           ~ 8 0
8 HSCS J021328-051146 ClG 02 13 28.384 -05 11 46.47           ~ 2 0
9 KROSS U-zuds z1 229 QSO 02 18 30.772 -05 01 23.66           ~ 2 0
10 HSCS J021832-050059 ClG 02 18 31.67 -05 00 59.5           ~ 22 0
11 XLSSC 063 ClG 02 18 37.24 -05 40 24.9           ~ 5 0
12 SDSS J021837.24-054024.9 AGN 02 18 37.2442758696 -05 40 24.907263456           ~ 4 0
13 SDSS J021905.66-051039.4 QSO 02 19 05.6615655768 -05 10 39.439818192       20.43   ~ 11 0
14 RCS J022056-0333.3 ClG 02 20 55 -03 33.5           ~ 20 0
15 SDSS J022129.20-040532.9 QSO 02 21 29.203 -04 05 32.94           ~ 2 0
16 MCG-01-07-007 AGN 02 24 02.6535882792 -04 41 36.266806284   14.91   13.86 13.54 ~ 34 0
17 SDSS J022445.63-030224.7 QSO 02 24 45.6413651328 -03 02 24.777645648   18.80   17.39   ~ 11 0
18 XLSSC 045 ClG 02 25 29 -04 15.7           ~ 4 0
19 XLSSC 090 ClG 02 28 29 -04 51.4           ~ 11 0
20 XLSSC 210 ClG 02 30 30 -05 13.5           ~ 1 0
21 HSCS J023039-045927 ClG 02 30 38.7 -04 59 27           ~ 10 0
22 XLSSU J023322.1-045506 C?G 02 33 22 -04 55.1           ~ 1 0
23 XBCS J231917.1-551928 ClG 23 19 17.1 -55 19 28           ~ 12 0
24 XLSSU J232212.6-553259 C?G 23 22 13 -55 33.0           ~ 1 0
25 XLSSC 595 ClG 23 26 45.901 -53 48 39.30           ~ 3 0
26 [SSB2012] 11 ClG 23 27 13.7 -56 03 41           ~ 4 0
27 XLSSU J232936.7-555349 C?G 23 29 36 -55 53.8           ~ 1 0
28 XLSSU J233006.5-545553 C?G 23 30 06 -54 55.9           ~ 1 0
29 XBCS J233204.4-551243 ClG 23 32 04.4 -55 12 43           ~ 12 0
30 XLSSU J233809.3-555350 C?G 23 38 09 -55 53.8           ~ 1 0
31 XLSSC 650 ClG 23 40 24 -55 09.8           ~ 1 0
32 XLSSC 649 ClG 23 40 29 -53 43.8           ~ 1 0
33 ACT-CL J2344.7-4243 ClG 23 44 43.9 -42 43 11           ~ 229 0
34 XLSSC 651 ClG 23 46 00.901 -56 11 04.80           ~ 2 0
35 SCSO J234703-535051 ClG 23 47 03 -53 50.9           ~ 2 0
36 XLSSU J234705.7-535653 C?G 23 47 06 -53 56.9           ~ 1 0

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