X-ray binaries in M51 I: catalog and statistics


Abstract in English

We used archival data from the emph{Chandra X-ray Observatory} (emph{Chandra}) and the emph{Hubble Space Telescope}, to identify 334 candidate X-ray binary (XRB) systems and their potential optical counterparts in the interacting galaxy pair NGC 5194/5195 (M51). We present the catalog and data analysis of X-ray and optical properties for those sources, from the deep $892$ ks emph{Chandra} observations, along with the magnitudes of candidate optical sources as measured in the $8.16$ ks emph{HST} observations. The X-ray luminosity function of the X-ray sources above a few times $10^{36}, {rm erg,s^{-1}}$ follows a power law $N(>L_{X,b})propto L_{X,b}^{1-alpha}$ with $alpha=1.65pm0.03$. Aproximately 80% of sources are variable over a 30 day window. Nearly half of the X-ray sources (173/334) have an optical counterparts within $0{mbox{$.!!^{primeprime}$}}5$.

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