Free Astronomy Magazine July-August 2016

SPACE CHRONICLES verse. One assumes that the seeds grow out of black holes with a mass about ten to a hundred times greater than our Sun, as expected for the collapse of a massive star. The black hole seeds then grew through mergers with other small black holes and by pulling in gas from their surroundings. However, they would have to grow at an unusually high rate to reach the mass of supermassive black holes already discovered in the billion years young Universe. The new findings support another scenario where at least some very massive black hole seeds with 100000 times the mass of the Sun formed directly when a massive cloud of gas collapses. In this case the growth of the black holes would be jump started, and would proceed more quickly. Black hole seeds cre- ated through the collapse of a mas- T his image shows more clearly the supermas- sive black hole seed OBJ29323, as it is seen by the NASA Chandra Space Tele- scope. The properties of the X-ray data match those predicted by models pro- duced by the Italian re- search team. [NASA/CXC/Sc uola Normale Superiore/ Pacucci] T his image “shows” one of two detected supermas- sive black hole seeds, OBJ29323, as it is seen by the NASA/ESA Hubble Space Telescope. [NASA/STScI/ESA] than starting small and growing at a very fast rate.” Andrea Grazian, a co-author from the National Insti- tute for Astrophysics in Italy ex- plains: “Black hole seeds are ex- tremely hard to find and confirming their detection is very difficult. However, we think our research has uncovered the two best candidates so far.” Even though both black hole seed candidates match the theoreti- cal predictions, further observations are needed to confirm their true na- ture. To fully distinguish between the two formation theories, it will also be necessary to find more can- didates. The team plans to conduct follow-up observations in X-rays and in the infrared range to check whether the two objects have more of the properties expected for black hole seeds. Upcoming observatories, like the NASA/ESA/CSA James Webb Space Telescope and the European Extremely Large Telescope will cer- tainly mark a breakthrough in this field, by detecting even smaller and more distant black holes. sive cloud of gas bypass any other in- termediate phases such as the forma- tion and sub- sequent de- struction of a massive star. “There is a lot of contro- versy over which path these black holes take,” said co-au- thor Andrea Ferrara also of Scuola Nor- male Superiore. “Our work suggests we are converging on one answer, where black holes start big and grow at the normal rate, rather n