Overdensity of X-ray Sources in the Field of Nearby Clusters of Galaxies

Murat Hudaverdi; Hideyo Kunieda; Takeshi Tanaka; Yoshito Haba; Akihiro Furuzawa; Yuzuru Tawara; E. Nihal Ercan

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arXiv · 0803.2575

Overdensity of X-ray Sources in the Field of Nearby Clusters of Galaxies

Murat Hudaverdi·Hideyo Kunieda·Takeshi Tanaka·Yoshito Haba·Akihiro Furuzawa·Yuzuru Tawara·E. Nihal Ercan

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Abstract

Two nearby clusters of galaxies: A194 (z=0.018) and A1060 (z=0.0114) have been analyzed for their X-ray point source properties with XMM-Newton EPIC-PN data. A multi-band source detection technique was applied to both of the clusters, resulting in 46 sources from the A194 field and 32 sources from the A1060 field, respectively. The cumulative log(N)-log(S) for a flux limit of Fx~10E-14 ergs cm-2 s-1 is calculated and compared with that of the Lockman Hole. A ~3 sigma excess of X-ray sources is found for the cluster regions. Considering the higher fraction observed in optical studies from the clusters, we estimate that the cluster source density is 6 times higher than the blank field source density, and 15 times higher than the local group. Our X-ray selected sources have luminosity values between 10E(39.6) 10E(40.5) ergs/s, at which point the source density becomes comparable to that of the blank-field level. Considering this confined low luminosity range and the X-ray to optical luminosity ratios (L_X/L_B), the observed overdensity is ascribed to AGN fueling by its infall into cluster environment for Lx < 10E(40.5) ergs/s in the X-ray luminosity function. Whereas, the quenching of AGN activity by the deep cluster potential explains why the excess of the source density vanishes for the brighter sources.

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Murat Hudaverdi, Hideyo Kunieda, Takeshi Tanaka, Yoshito Haba, Akihiro Furuzawa, Yuzuru Tawara, E. Nihal Ercan. 2008-03-18. Overdensity of X-ray Sources in the Field of Nearby Clusters of Galaxies. https://arxiv.org/abs/0803.2575

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