NASA announced that their Swift satellite recorded a rising tide of high-energy X-rays, revealing the existence of a previously unknown black hole near the center of the Milky Way Galaxy.
The high-energy X-rays are a product of a rare X-ray nova. In a statement released by NASA, Neil Gehrels, a mission investigator at NASA's Goddard Space Flight Center in Greenbelt, MD, stated: "Bright X-ray novae are so rare that they're essentially once-a-mission events and this is the first one Swift has seen. This is really something we've been waiting for."
According to the Examiner, Swift has recorded the rare event on three separate occasions. Swift's BAT (Burst Alert Telescope) recorded two consecutive intense X-ray flashes on Sept, 16th of this year. On Oct. 8th of this year, Swift's BAT recorded another explosion of X-rays. It was that explosion that lead to the discovery of the black hole.
NASA says scientists believe the black hole must be a member of a low-mass X-ray binary (LMXB) system. A stream of gas flows from the normal star and enters into a storage disk around the black hole. In most LMXBs, the gas in the disk spirals inward, heats up as it heads toward the black hole, and produces a steady stream of X-rays.
Boris Sbarufatti, an astrophysicist at Brera Observatory in Milan, Italy working with other Swift team members at Penn State University stated"The pattern we're seeing is observed in X-ray novae where the central object is a black hole. Once the X-rays fade away, we hope to measure its mass and confirm its black hole status."Black Holes
NASA E/PO, Sonoma State University, Aurore Simonnet
This artist's drawing shows a supermassive black hole in the center of a galaxy. The black hole is surrounded by a cloud of material that is spiraling into it.
NASA defines a black hole as a place in space where the gravitational pull is so strong even light cannot get out. The gravity is so powerful because matter has been squeezed into a tiny space, which can happen when a star is dying.
Because no light can escape, black holes are invisible to the naked eye and even most telescopes. Specially equipped space telescopes can help detect black holes by seeing how stars very close to black holes act differently from other stars.
EarthSky calls black holes the "burying grounds of extremely massive stars". After a supernova explosion occurs, the massive core is left behind. Because there is not enough balancing force after the explosion, gravity pulls the core together to a point where the escape velocity exceeds the speed of light. This prevents light or any other form of radiation from escaping into space, leaving nothing but a black void where the star once stood.
Named after the coordinates of its position in space, the nova is located in the Sagittarius constellation, just a few degrees from the center of the Milky Way galaxy. According to Space Daily, astronomers believe Swift J1745-26 resides approximately 20,000 to 30,000 light-years away from earth. The nova peaked in hard X-rays on Sept. 18, 2012 and reached an intensity equivalent to that of Crab Nebula. Crab Nebula is a remnant of a supernova that high-energy observatories use as a calibration target. It is also considered one of the brightest sources beyond the solar system.