X-ray variability in the 2 Ms Chandra Deep Field South

This movie shows the variability of X-ray sources (mostly AGNs) in the Chandra Deep Field South (Giacconi et al. 2001, Luo et al. 2008). The observations have now been extended to 2 Msec, and are unevenly distributed over a period of 7 years, as shown by the bar at the bottom of the image.

Note that not all sources that appear to vary in this movie are actually variable: the faintest ones, seem to appear and disappear due to statistical fluctuations. However the variability observed in the brightest ones is real, and our work (Paolillo et al. 2004, Paolillo et al. 2008 in prep) shows that at least 50% of the sources are variable, and that the fraction of variable AGNs may be be as large as 95%.

Variability catalogs for the first 1 Ms studied in Paolillo et al. 2004 (Apj, 611, 93) are available here:

Readme file, X-ray variability catalog

The analysis of the whole 2 Ms dataset (see Luo et al. 2008) is in progress and will be published soon.

Figure 1: The Chandra Deep Field Sources movie. The bar at the bottom of the image shows the epoch of the observations. The weird shape of the background (dark red) is due to the shape of the Chandra camera. The images have been corrected for instrumental effects (exposure variations, PSF broadening etc.) to mimick what a "clean" observation would look like. The colors are shown in logaritmic scale which enhances faint sources.