The candidate filament close to the 3C295 galaxy cluster: optical and X-ray spectroscopy
arXiv:0804.2143 · doi:10.1051/0004-6361:20079338
Abstract
We present a detailed analysis of the overdensity of X-ray sources colse to the 3C 295 galaxy cluster (z=0.46) to assess whether it is associated with a filament of the large-scale structure of the Universe. We obtained optical spectra of the optical counterparts of eleven sources associated with the filament, finding that one is at z=0.474. This is a type 1 AGN at 1.5 arcmin from the cluster center. We found three more sources with a redshift in the range 0.37 - 0.53. We extracted the stacked X-ray spectrum of 47 X-ray sources belonging to the putative filament. We found a significant narrow (at the resolution of the Chandra ACIS-I) line at E ~ 4.4 keV, the energy of the iron Kalpha line at the redshift of the cluster. The detection of this line is confirmed at a confidence level of better than 3sigma and its energy is constrained to be in the range 6.2--6.47 (at a 90% confidence level), excluding an identification with the 6.7 helium-like iron line from the hot cluster ICM at better than 4 sigma. We conclude that the detection of the redshifted line is a strong indication that at least several of the excess sources lie at z ~ 0.46 and that AGNs are efficient tracers of the ``filament'' connected with the central cluster of galaxies.
arXiv comment7 Pages 9 .ps figures, A&A in press
References in corpus (21)
- Halo Properties in Cosmological Simulations of Self-Interacting Cold Dark Matter
- The X-ray virial relations for relaxed lensing clusters observed with Chandra
- Chandra Discovery of a Tree in the X-ray Forest towards PKS 2155-304: the Local Filament?
- Clustering Segregation With UV Luminosity in Lyman-Break Galaxies at z~3 and Its Implications
- Spectroscopic Confirmation of a Large AGN Population in Clusters of Galaxies
- Tracing the Warm-Hot Intergalactic Medium at Low Redshift: X-ray Forest Observations Towards H1821+643
- A Chandra study of X-ray sources in the field of the z=2.16 radio galaxy MRC 1138-262
- The coincidence and angular clustering of Chandra and SCUBA sources
- An Unexpectedly High AGN Fraction in Red Cluster Galaxies
- The Origin of the Spatial Distribution of X-ray luminous AGN in Massive Galaxy Clusters
- The Spatial Clustering of Distant, z~1, Early-Type Galaxies
- Imaging Large Scale Structure in the X-ray Sky
- Chandra study of an overdensity of X-ray sources around two distant (z~0.5) clusters
- Warm-hot intergalactic baryons revealed
- X-ray source overdensities in Chandra distant cluster fields: a new probe to map the cosmic tapestry?
- Chandra Observations of Unresolved X-ray Sources around two Clusters of Galaxies
- The Evolution of the Luminosity Function in Deep Fields: A Comparison with CDM Models
- Micro-Jy radio sources in the z=0.83 cluster MS1054-03
- Missing baryons and the soft X-ray background
- The faint X-ray Source Population near 3C 295
- Probing the warm Inter-Galactic Medium through absorption against Gamma Ray Bursts X-ray afterglows