Publications (4)0.88 Total impact
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ABSTRACT: We present a statistical analysis of the Chandra observation of the source field around the 3C 295 galaxy cluster (z=0.46). Three different methods of analysis, namely a chip by chip logNlogS, a two dimentional KolmogorovSmirnov (KS) test, and the angular correlation function (ACF) show a strong overdensity of sources in the NorthEast of the field, that may indicate a filament of the large scale structure of the Universe toward 3C 295.07/2004;  [Show abstract] [Hide abstract]
ABSTRACT: We present a statistical analysis of the Chandra observation of the source field around the 3C 295 galaxy cluster (z=0.46) aimed at the search for clustering of Xray sources. We applied three different methods of analysis, all suggesting a strong clustering in the field on scales of a few arcmin. In particular 1) the logNlogS computed separately for the four ACISI chips reveals that there is a significant (3.2 sigma in the 0.52 keV, 3.3 sigma in the 210 keV and 4.0 sigma in the 0.510 keV band) excess of sources to the NorthNorth East and a void to the South of the central cluster. 2) the two point, twodimensional KolmogorovSmirnov (KS) test, shows the probability that the sources are uniformly distributed is only a few percent. 3) a strong spatial correlation emerges from the study of the angular correlation function of the field: the angular correlation function (ACF) shows a clear signal on scales of 0.5  5 arcmin, correlation angle in the 0.57 keV band theta = 8.5^{+6.5}_{4.5}, 90% confidence limit (assuming a power law ACF with slope gamma=1.8). This correlation angle is 2 times higher than that of a sample of 8 ACISI field at the 2.5 sigma confidence level. The above scales translate to 0.2  2 Mpc at the cluster redshift, higher than the typical cluster core radius, and more similar to the size of a ``filament'' of the large scale structure. Comment: 12 pages, 20 .ps figures, accepted for pubblication in A&AProceedings of the International Astronomical Union 03/2004;  [Show abstract] [Hide abstract]
ABSTRACT: We present a statistical analysis of the Chandra observation of the source field around the 3C 295 galaxy cluster ($z=0.46$). The logNlogS of this field is in good agreement with that computed for the Chandra Deep Field South in this work and in previous ones. Nevertheless, the logNlogS computed separately for the four ACISI chips reveals that there is a significant excess of sources to the NorthNorth East and a void to the South of the central cluster. Such an asymmetric distribution is confirmed by the twodimensional KolmogorovSmirnov test, which excludes ($P \sim 3%$) a uniform distribution. In addition, a strong spatial correlation emerges from the study of the angular correlation function of the field: the angular correlation function is above that expected for Xray sources on a few arcmin scales. In synthesis, the present analysis may indicate a filament of the large scale structure of the Universe toward 3C 295. This kind of studies may openup a new way to map (with high efficiency) highdensity peaks of large scale structures at highz. Comment: 4 pages, 6 ps figures, to appear in the proceedings of the "The Restless High Energy Universe" Workshop, Amsterdam, May 58, 2003Nuclear Physics B  Proceedings Supplements 10/2003; · 0.88 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We present a statistical analysis of the Chandra observation of the source field around the 3C 295 galaxy cluster ($z=0.46$). Three different methods of analysis, namely a chip by chip logNlogS, a two dimentional KolmogorovSmirnov (KS) test, and the angular correlation function (ACF) show a strong overdensity of sources in the NorthEast of the field, that may indicate a filament of the large scale structure of the Universe toward 3C 295. Comment: 2 pages, 4 postscript figures; to appear in the proceedings of the "Multiwavelength Cosmology" workshop, Mykonos, Greece, 2003, June 172110/2003;
Publication Stats
9  Citations  
0.88  Total Impact Points  
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2003

Smithsonian Institution
Washington, Washington, D.C., United States
