March 28, 2016

God is the photograph of everything at once

This Map Is the Most Complete Catalog Ever Made of Everything in Our Sky

The second ROSAT all-sky survey (2RXS) catalogue:

We present the second ROSAT all-sky survey source catalogue, hereafter referred to as the 2RXS catalogue. The 2RXS catalogue is the second publicly released ROSAT catalogue of point-like sources obtained from the ROSAT all-sky survey observations performed between June 1990 and August 1991, and is an extended and revised version of the 1RXS catalogue. We have developed shell scripts containing a collection of individual MIDAS/EXSAS commands to create the new data products in addition to the source detection parameters. X-ray control images were produced, which show the source and background extraction regions, selected by the timing and spectral analysis procedures, to allow the user to validate the derived parameters. Thirty-one large extended regions with diffuse emission and embedded point sources were identified and excluded from the present analysis. The 2RXS catalogue contains about 135,000 X-ray detections down to a detection likelihood of 6.5 in the 0.1-2.4 keV energy band. Our simulations show that the expected spurious content of the catalogue is a strong function of detection likelihood, and the full catalogue is expected to contain about 30 % spurious detections. A more conservative likelihood threshold of 9, on the other hand, yields about 71,000 detections with a 5 % spurious fraction. We recommend thresholds appropriate to the scientific application. X-ray images with overlaid X-ray intensity contours provide an additional product to allow the user to evaluate the detection likelihood. Intra-day variability in the X-ray light curves was quantified based on the normalised excess variance and a maximum amplitude variability analysis. X-ray spectral fits were performed using three basic models, a power law, a thermal plasma emission model, and black-body emission. The 2RXS catalogue provides the deepest and cleanest X-ray all-sky survey catalogue before eROSITA data will become available.
Larger Image if you....


Aitoff projection in Galactic coordinates of the sky distribution of 2RXS sources. The size of the symbols scales with the source count rate and the colours represent different spectral characteristics (increasing hardness ratio 1 from red (soft) to blue (hard).
Posted by gerardvanderleun at March 28, 2016 4:32 PM
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Love that! I've been looking for that without even knowing I was wondering! Wonderfull.

Posted by: DeAnn at March 29, 2016 8:09 AM

This Map Is the Most Complete Catalog Ever Made By a pPre-schooler of Everything in Our


Posted by: BillH at March 29, 2016 1:48 PM