2006ApJS..166..211Z

We present the properties of the discrete X-ray sources detected in our monitoring survey of the Antennae galaxies with Chandra ACIS-S. We detect ∼70 sources down to a typical luminosity of 7x10³⁷ ergs/s in each of the six monitoring observations. In the co-added observation (which has a total exposure of 411 ks) we detect a total of 120 sources down to a luminosity of 2-5x10³⁷ ergs/s, depending on the local background. Fifteen sources have a strong extended component. Fourteen of the pointlike sources have luminosities above 10³⁹ ergs/s, at least in one exposure, which qualifies them as ultraluminous X-ray sources (ULXs). Ten of the ULXs show long-term variability, while one is observed only once, suggesting that it is a transient source. We find that 25 sources exhibit long-term variability clearly associating them with accreting compact objects. Twenty-one sources also show spectral variability. However, their variability patterns are diverse, indicating that they belong to different source classes. Finally, we find a weak excess of hard sources at the low luminosities that we tentatively associate with pulsar X-ray binaries.