– For the first time ever, astronomers have discovered extraordinary cosmic objects erupting in X-ray.
These mysterious objects are bright cosmic flares that become about a hundred times brighter in less than a minute, before returning to original X-ray levels after about an hour.
At their peak, the objects give off hundreds to thousands of times more X-rays than typical binary systems where a star is orbiting a black hole or neutron star. For now, the nature of these flares is unknown.
Astronomers have rejected the theory that the objects are magnetars – young neutron stars with powerful magnetic fields known to produce bright and rapid flares in X-rays.
The behavior of the newly discovered very bright flares differs from what we know about magnetars, which only take a few seconds to tens of seconds to decline in X-rays after a flare. Secondly, these new flaring objects are found in populations of old stars in elliptical galaxies, which are spherical or egg-shaped galaxies that are composed mostly of older stars.
This is an entirely new phenomenon that still remains unknown and must be further investigated.
When these cosmic objects are not flaring, these sources appear to be normal binary systems where a black hole or neutron star is pulling material from a companion star similar to the Sun. This indicates that the flares do not significantly disrupt the binary system.
According to NASA, “one idea is that the flares represent episodes when matter being pulled away from a companion star falls rapidly onto a black hole or neutron star. This could happen when the companion makes its closest approach to the compact object in an eccentric orbit. Another explanation could involve matter falling onto an intermediate-mass black hole, with a mass of about 800 times that of the Sun for one source and 80 times that of the Sun for the other.”
The cosmic objects were discovered with NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton observatory.