Found this article with some more comments from Chandra team members. And the original x-ray image showing Pluto slightly bigger as a dot. So the image we see everywhere (and top of this page) is a highly blown-up image of Pluto in x-ray

Article; http://www.forbes.com/sites/startswithabang/2016/09/14/thats-no-comet-thats-pluto-comet-like-tail-and-x-rays-discovered-at-solar-systems-edge/
The “real” x-ray image of Pluto; http://blogs-images.forbes.com/startswithabang/files/2016/09/8photons.png

To get an idea “A high-quality digital camera based on a multi-megapixel array will typically record an image by collecting of order 10^5 photons per pixel”. Although we can’t compare this 1 on 1…it means that if you make a photo with your 5Megapixel camera, 1 million x 5 million photons are being used (with a shutter time of a fraction of a second)….thats alot of photons.

If i read the paper and google on, its still not clear to me. But they use a term “cts/s” which is some sort of unit for photon-count. So i guess they mean 7 photons per second, and not in total. Could anyone clear this up? Thanks in advance

Quote from the paper;
Added to the 2014 results, we find a total Pluto x-ray signal of 6.55 ± 1.28 cts, a total count rate of 3.7 x 10-5cps, and a 5.4σ detection of Pluto in an 11×11 pixel (5.5”x5.5”) box centered on its ephemeris position.