2016A&A...592A..11K


Query : 2016A&A...592A..11K

2016A&A...592A..11K - Astronomy and Astrophysics, volume 592A, 11-11 (2016/8-1)

The XXL Survey. XII. Optical spectroscopy of X-ray-selected clusters and the frequency of AGN in superclusters.

KOULOURIDIS E., POGGIANTI B., ALTIERI B., VALTCHANOV I., JAFFE Y., ADAMI C., ELYIV A., MELNYK O., FOTOPOULOU S., GASTALDELLO F., HORELLOU C., PIERRE M., PACAUD F., PLIONIS M., SADIBEKOVA T. and SURDEJ J.

Abstract (from CDS):

Context. This article belongs to the first series of XXL publications. It presents multifibre spectroscopic observations of three 0.55deg2 fields in the XXL Survey, which were selected on the basis of their high density of X-ray-detected clusters. The observations were obtained with the AutoFib2+WYFFOS (AF2) wide-field fibre spectrograph mounted on the 4.2m William Herschel Telescope.
Aims. The paper first describes the scientific rationale, the preparation, the data reduction, and the results of the observations, and then presents a study of active galactic nuclei (AGN) within three superclusters.
Methods. To determine the redshift of galaxy clusters and AGN, we assign high priority to a) the brightest cluster galaxies (BCGs), b) the most probable cluster galaxy candidates, and c) the optical counterparts of X-ray point-like sources. We use the outcome of the observations to study the projected (2D) and the spatial (3D) overdensity of AGN in three superclusters.
Results. We obtained redshifts for 455 galaxies in total, 56 of which are counterparts of X-ray point-like sources. We were able to determine the redshift of the merging supercluster XLSSC-e, which consists of six individual clusters at z∼0.43, and we confirmed the redshift of supercluster XLSSC-d at z∼0.3. More importantly, we discovered a new supercluster, XLSSC-f, that comprises three galaxy clusters also at z∼0.3. We find a significant 2D overdensity of X-ray point-like sources only around the supercluster XLSSC-f. This result is also supported by the spatial (3D) analysis of XLSSC-f, where we find four AGN with compatible spectroscopic redshifts and possibly one more with compatible photometric redshift. In addition, we find two AGN (3D analysis) at the redshift of XLSSC-e, but no AGN in XLSSC-d. Comparing these findings with the optical galaxy overdensity we conclude that the total number of AGN in the area of the three superclusters significantly exceeds the field expectations. All of the AGN found have luminosities below 7x1042erg/s.
Conclusions. The difference in the AGN frequency between the three superclusters cannot be explained by the present study because of small number statistics. Further analysis of a larger number of superclusters within the 50deg2 of the XXL is needed before any conclusions on the effect of the supercluster environment on AGN can be reached.

Abstract Copyright: © ESO, 2016

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

Nomenclature: Fig. 2, Table 2: [PCG2016] XLSSC-a (No. f) added.

Simbad objects: 24

goto Full paper

goto View the references in ADS

Number of rows : 24
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 3XLSS J021046.2-060854 AGN 02 10 46.291 -06 08 54.45           ~ 2 0
2 XLSSC 082 ClG 02 10 51 -06 10.4           ~ 2 0
3 3XLSS J021053.0-061809 AGN 02 10 53.114 -06 18 10.84           ~ 2 0
4 HSCS J021056-061154 ClG 02 10 57.80 -06 11 56.8           ~ 15 0
5 XLSSC 084 ClG 02 11 04 -06 12.7           ~ 9 0
6 XLSSC 086 ClG 02 11 14 -06 09.7           ~ 2 0
7 [PCG2016] XLSSC-e SCG 02 11.5 -06 12           ~ 3 0
8 XLSSC 085 ClG 02 11 29 -06 11.8           ~ 8 0
9 SDSS J021153.59-053811.6 AGN 02 11 53.6032326741 -05 38 11.599063693           ~ 3 0
10 XLSSC 081 ClG 02 12 11 -06 12.6           ~ 2 0
11 3XLSS J021213.7-060408 AGN 02 12 13.657 -06 04 07.00           ~ 4 0
12 XMMXCS J021226.8-053734.6 ClG 02 12 26.80 -05 37 34.6           ~ 12 0
13 XLSSC 098 ClG 02 12 28 -06 04.6           ~ 11 0
14 [PCG2016] XLSSC-f SCG 02 12.5 -05 49           ~ 1 0
15 XLSSC 117 ClG 02 12.5 -05 49           ~ 2 0
16 SDSS J021235.99-053211.6 QSO 02 12 35.9972694120 -05 32 11.638699728           ~ 7 0
17 SDSS J021309.12-055142.8 QSO 02 13 09.127 -05 51 42.81           ~ 6 0
18 NAME XMM-LSS Field reg 02 18 00 -07 00.0           ~ 211 0
19 [PCG2016] XLSSC-a SCG 02 26.2 -04 04           ~ 2 0
20 HSCS J022725-043237 ClG 02 27 25.9 -04 32 15           ~ 30 0
21 [BPR2008] WL07 ClG 02 27 40.3 -04 51 31           ~ 29 0
22 RzCS 185 ClG 02 28 03.4 -04 51 03           ~ 24 0
23 [PCG2016] XLSSC-d SCG 02 28.9 -05 03           ~ 2 0
24 ACO 1958 ClG 14 43 13 +30 58.3           ~ 53 0

To bookmark this query, right click on this link: simbad:objects in 2016A&A...592A..11K and select 'bookmark this link' or equivalent in the popup menu


2022.08.12-08:16:44

© Université de Strasbourg/CNRS

    • Contact