Astronomers have discovered the source and cycle of mysterious ultra-bright gamma ray flashes, which runs on a clockwork 162-days at a distance of 15,000 light years away from Earth. The “gamma ray heartbeat” may reveal a link to a rare “microquasar” star system called SS 433 –a binary system comprising a compact “microquasar, a black hole or neutron star submerged in a dense, bright disk of gas spitting out huge amounts of X-rays, gamma-rays, and radio waves, plus hydrogen gas flying at speeds of 25 percent of the speed of light.
SS433 is a small-scale version of quasars that are present within our Milky Way Galaxy first discovered in 1977–orbiting a massive companion star, creating an enormous disk of hot gas around the dead compact star.
The brilliant, luminous heartbeat “is unexpected from previously published theoretical models” and is yet another reason why “SS 433 continues to perplex observers at all frequencies and theoreticians alike,” reports a study published in Nature Astronomy based on more than ten years of gigaelectronvolt gamma-ray data from the Fermi Gamma-ray Space Telescope. A radio image of SS433, with particles streaming away from the black hole in a corkscrew pattern is shown above.
The corkscrew shape is created by a phenomenon known as precession; as they move outwards through space, the two jets shown are slowly tumbling around an axis in a similar way to the motion of a gyroscope or a spinning top slowing down, the orientation of their rotational axes changing as they do so. The scale of this corkscrew is enormous, at 5000 times the size of the Solar System.
Locked in Orbit with a Dead Star
SS433, one of the most exotic star systems known to astronomers, consist of a massive, hot star locked in a mutual orbit with a compact object, a black hole or neutron star, which has produced an accretion disk with jets. Material transfers from the massive star into an accretion disk surrounding the compact object blasting out two jets of ionized gas in opposite directions – at about 1/4 the speed of light. Radiation from the jet tilted toward the observer is blueshifted, while radiation from the jet tilted away is redshifted. The binary system itself completes an orbit in about 13 days while the jets precess (wobble like a top) with a period of about 162 days .
Linked to a Large Hydrogen Gas Cloud?
Another odd source of gamma rays, a large cloud of hydrogen gas called Fermi J1913+0515 about 100 light years from SS 433, is being charged with some kind of energetic emission, causing the flashes of light. To determine if there’s a link between SS 433 and Fermi J1913+0515, Jian Li, who co-led the new study and serves as Humboldt Fellow at Deutsches Elektronen-Synchrotron (DESY) in Germany, examined the precessional period of SS 433. It’s disk wobbles like a spinning top over a period of about 162 days, causing the jets to get twisted into spiral shapes. The Fermi data revealed that the period of the gamma ray heartbeat matched SS 433’s precessional period, peaking at 162 days, which is consistent with the precession period of the jet.
The gamma ray heartbeat, however, should be too distant for a connection with SS 433, reports Motherboard Science, and is not located in the direct path of its jets, which models also predict would collapse long before they could travel across 100 light years and illuminate the sky with such intense energy. Another potential explanation is that the heartbeat is illuminated by more diffuse and unstructured outflows of gas and particles generated by the disk’s precession, rippling out to Fermi J1913+0515 and light it up in this unique way.