It is located 2,537,000 light years from Earth and together with the Milky Way and the Triangle Galaxy, they make up the three large spiral galaxies of the Local Group. Now, after decades of searching, a team of astrophysicists has discovered a difficult-to-locate object in the universe: a neutron star. This stellar corpse (or remnant) has been located thanks to ESA’s XMM-Newton space telescope.
The Andromeda Galaxy is very popular with astronomers as it is the farthest visible object with the naked eye from Earth and the most similar to the Milky Way, making it an interesting natural laboratory for scientists. Telescopes have examined the entire electromagnetic spectrum in detail for decades, but until now, a neutron star has never been found.
Neutron stars rotate so rapidly that they can even sweep regular pulses of radiation toward Earth, like a cosmic beacon, which can “turn on” and “off” as it spins. If they “cannibalize” a neighboring star, the neutron star spins even faster.
Data from the X-ray telescope made it possible to locate the signal from an unusual source of an extremely fast spinning neutron star. According to experts, it appears to be feeding on a neighboring star that orbits every 1.3 days, spinning it every 1.2 seconds. It is certainly unusual and exotic.
“ We were expecting to detect periodic signals among the brightest X-ray objects in Andromeda, but bright X-ray pulsars as persistent as this one are still somewhat peculiar . We searched through archival Andromeda data spanning 2000-13, but it wasn’t until 2015 that we were finally able to identify this object in the galaxy’s outer spiral in just two of 35 measurements, ”explains Gian Luca Israel, study co-author.
“It could be what we call a peculiar low-mass X-ray pulsar , but we need to acquire more observations of the pulsar and its companion to help determine which is the most likely scenario,” says Paolo Esposito, co-author of the work.
The finding has been published in the Monthly Notices of the Royal Astronomical Society.
