2014A&A...567A..83K


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.03CEST22:32:33

2014A&A...567A..83K - Astronomy and Astrophysics, volume 567A, 83-83 (2014/7-1)

X-ray AGN in the XMM-LSS galaxy clusters: no evidence of AGN suppression.

KOULOURIDIS E., PLIONIS M., MELNYK O., ELYIV A., GEORGANTOPOULOS I., CLERC N., SURDEJ J., CHIAPPETTI L. and PIERRE M.

Abstract (from CDS):

We present a study of the overdensity of X-ray-selected active galactic nuclei (AGN) in 33 galaxy clusters in the XMM-LSS field (The XMM-Newton Large Scale Structure Survey), up to redshift z=1.05 and further divided into a lower (0.14≤z≤0.35) and a higher redshift (0.43≤z≤1.05) subsample. Previous studies have shown that the presence of X-ray-selected AGN in rich galaxy clusters is suppressed, since their number is significantly lower than what is expected from the high galaxy overdensities in the area. In the current study we have investigated the occurrence of X-ray-selected AGN in low (<Lx,bol≥2.7x1043erg/s) and moderate (<Lx,bol≥2.4x1044erg/s) X-ray luminosity galaxy clusters in an attempt to trace back the relation between high-density environments and nuclear activity. Owing to the wide contiguous XMM-LSS survey area, we were able to extend the study to the cluster outskirts. We therefore determined the projected overdensity of X-ray point-like sources around each cluster out to 6r500 radius, within δr500=1 annulus, with respect to the field expectations based on the X-ray source logN-logS of the XMM-LSS field. To provide robust statistical results we also conducted a consistent stacking analysis separately for the two z ranges. We investigated whether the observed X-ray overdensities are to be expected thanks to the obvious enhancement of galaxy numbers in the cluster environment by also estimating the corresponding optical galaxy overdensities, and we assessed the possible enhancement or suppression of AGN activity in clusters. We find a positive X-ray projected overdensity in both redshift ranges at the first radial bins, which however has the same amplitude as that of optical galaxies. Therefore, no suppression (or enhancement) of X-ray AGN activity with respect to the field is found, in sharp contrast to previous results based on rich galaxy clusters, implying that the mechanisms responsible for the suppression are not as effective in lower density environments. After a drop to roughly the background level between 2 and 3r500, the X-ray overdensity exhibits a rise at larger radii, significantly greater than the corresponding optical overdensity. The radial distance of this overdensity ``bump'', corresponding to ∼1.5-3Mpc, depends on the richness of the clusters, as well as on the overall X-ray overdensity profile. Finally, using the redshift information, photometric or spectroscopic, of the optical counterparts, we derive the spatial overdensity profile of the clusters. We find that the agreement between X-ray and optical overdensities in the first radial bins is also suggested in the 3-dimensional analysis. However, we argue that the X-ray overdensity ``bump'' at larger radial distance is at least partially a result of flux boosting by gravitational lensing of background quasi-stellar objects, confirming previous results. For high-redshift clusters, the enhancement of X-ray AGN activity in their outskirts appears to be intrinsic. We argue that a spatial analysis is crucial for disentangling irrelevant phenomena affecting the projected analysis, but we are still not able to report statistically significant results on the spatial overdensity of AGN in clusters or their outskirts because we lack the necessary numbers.

Abstract Copyright:

Journal keyword(s): galaxies: clusters: general - galaxies: active - X-rays: galaxies: clusters - galaxies: interactions - galaxies: evolution - large-scale structure of Universe

Simbad objects: 34

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Number of rows : 34

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 2XLSSd J021443.7-034920 ClG 02 14 43.71 -03 49 21.4           ~ 4 0
2 2XLSSd J021524.1-034332 ClG 02 15 23.99 -03 43 32.2           ~ 23 0
3 XCLASS 343 ClG 02 15 29 -04 40.9           ~ 11 0
4 XMMXCS J021547.2-045031.4 ClG 02 15 48 -04 50.5           ~ 5 0
5 ACO 334 ClG 02 16 12.2 -04 14 31           ~ 13 0
6 [RRB2014] RM J021735.3-051330.3 ClG 02 17 34.49 -05 13 18.5           ~ 14 0
7 NAME XMM-LSS Field reg 02 18 00 -07 00.0           ~ 171 0
8 XLSSC 077 ClG 02 18 05 -03 39.4           ~ 2 0
9 [FWT2010] SXDF07XGG ClG 02 18 25.11 -05 24 51.7           ~ 4 0
10 XCLASS 1706 ClG 02 19 44.31 -04 53 15.4           ~ 8 0
11 RzCS 024 ClG 02 20 23.5 -02 50 27           ~ 6 0
12 2XLSSd J022045.3-032556 ClG 02 20 45.46 -03 25 59.7           ~ 20 0
13 ACT-CL J0221.7-0346 ClG 02 21 45.8 -03 46 08           ~ 37 0
14 [RRB2014] RM J022156.4-054531.5 ClG 02 21 56 -05 45.4           ~ 11 0
15 [RRB2014] RM J022204.6-043300.1 ClG 02 22 05.6 -04 32 47           ~ 16 0
16 2XLSSd J022206.8-030314 ClG 02 22 06.85 -03 03 14.5           ~ 15 0
17 RzCS 315 ClG 02 22 53.6 -03 28 28           ~ 10 0
18 XMMXCS J022356.3-030556.8 ClG 02 23 56.300 -03 05 59.30           ~ 11 0
19 [RRB2014] RM J022358.0-043504.8 ClG 02 23 57.4 -04 35 17           ~ 17 0
20 XMMXCS J022401.1-050542.2 ClG 02 24 00.6 -05 05 25           ~ 20 0
21 [BPR2008] WL04 ClG 02 24 27.0 -04 50 34           ~ 11 0
22 CXOU J022428.2-041529 ClG 02 24 33.8 -04 14 15           ~ 27 0
23 XMMXCS J0224.9-0348 ClG 02 24 57.1 -03 48 53           ~ 26 0
24 RzCS 774 ClG 02 25 20.2 -03 48 30           ~ 14 0
25 RzCS 262 ClG 02 25 24.6 -04 40 45       17.3   ~ 33 0
26 2MASX J02253077-0414183 GrG 02 25 30.6 -04 14 20           ~ 31 0
27 2XLSSd J022532.3-035512 ClG 02 25 32.48 -03 55 09.5           ~ 15 0
28 XLSSU J022540.6-031121 ClG 02 25 40.6 -03 11 21           ~ 16 0
29 XCLASS 39 ClG 02 25 59.5 -02 49 35           ~ 8 0
30 RzCS 119 ClG 02 27 09.7 -04 18 05           ~ 27 1
31 2XLSSd J022722.4-032145 ClG 02 27 22.39 -03 21 39.2           ~ 23 0
32 RzCS 124 ClG 02 27 25.9 -04 32 15           ~ 27 0
33 2XLSSd J022738.1-031802 ClG 02 27 38.20 -03 17 56.9           ~ 21 0
34 [BPR2008] WL07 ClG 02 27 40.3 -04 51 31           ~ 29 0

    Equat.    Gal    SGal    Ecl

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2020.07.03-22:32:33

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