The Chandra X-ray Observatory is a satellite launched by NASA on July 23, 1999. Chandra is a space based telescope since the Earth’s atmosphere absorbs the vast majority of X-rays. Chandra is 100 times more sensitive to X-ray sources than previous X-ray telescopes.
A quasar is a shorter name for a quasi-stellar radio source. Originally astronmers did not know what quasars were. Now they are known to be the center of a massive galaxy surrounding a supermassive black hole. As matter falls into the supermassive black hole, energy is emitted back out. The energy output from a quasar can be up to a thousand times the energy output of the Milky Way. Chandra recently imaged one such quasar by the name of 3C186, and found that its interior is cooler than its exterior.
NASA’s Chandra X-ray Observatory has observed an unusual galaxy cluster that contains a bright core of relatively cool gas surrounding a quasar called 3C 186. This is the most distant such object yet observed, and could provide insight into the triggering of quasars and the growth of galaxy clusters.
This composite image of the cluster surrounding 3C 186 includes a new, deep image from Chandra (blue) showing emission from gas surrounding the point-like quasar near the center of the cluster. Chandra X-ray spectra show that the temperature of the gas drops from 80 million degrees on the outskirts of the cluster down to 30 million in the core. This drop in temperature occurs because intense X-ray emission from the gas cools it. Optical data from the Gemini telescope in yellow show the stars and galaxies in the field of view.
What makes this particular galaxy cluster and its strong cooling core interesting is its age. 3C 186 is about 8 billion light years away from Earth, making it the most distant known galaxy cluster to contain a prominent cooling core. Because of its large distance the cluster is being seen when the Universe is relatively young, at less than half its current age.
