A new study
Milky Way’s closest large galactic neighbor, the spiral Andromeda galaxy, has a strange and very well-kept secret that has successfully hidden from the prying eyes of curious astronomers for a long time. Andromeda features a powerful source of high-energy X-ray emissions. Its identity has remained an intriguing mystery – until now.
In March 2017, a team of astronomers reported that NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) mission has managed to detect the elusive object that is the culprit behind this high-energy radiation. The object, called Swift J0042.5+4112, is possibly a pulsar – a newborn neutron star that is the extremely dense, city-sized corpse of a doomed massive star that has perished in a fiery, brilliant. and beautiful supernova blast.
image credit: sci-news.com
Born spinning wildly, as they emerge, much like the Phoenix Bird of Greek mythology, from the raging funeral pyre of their massive progenitor stars, pulsars are highly magnetized objects, and Swift J0042.5+4112 shows a spectrum that is very similar to known pulsars inhabiting our own Milky Way galaxy.
This new interpretation of the identity of the mysterious object haunting Andromeda is based on its emission of high-energy X-rays, which NuSTAR is uniquely capable of measuring. Furthermore, Swift J0042.5+4112 is likely a binary system, in which material from a companion star gets sipped up by the vampire-like pulsar, which then spews out high-energy radiation, as the stolen material grows hotter and hotter and hotter.
Virgо Gаlаxу Cluster
Spiral galaxies like our Milky Way, and the nearby Andromeda, are majestic, starlit pinwheels twirling elegantly in space. Both our Milky Way and Andromeda are the two largest inhabitants of the Local Galaxy Group, which also hosts about 40 smaller galactic constituents.
The Local Group is a few million light-years across, though this is a small region when compared to the immense galaxy clusters. Enormous galaxy clusters can host literally hundreds of resident galaxies. Our own Local Group is situated near the outer limits of the Virgo Galaxy Cluster whose core is about 50 million light-years away from us.
image credit: tenbyobservatory.com
Sоlving The Andromeda Galaxy’s Bright Mуѕtеrу
The new study uses numerous different observations of the mysterious, bright, and bewildering object dancing in Andromeda. The observations of this intriguing object were derived from various spacecrafts. In 2013, NASA’s Swift satellite reported it as a high energy source, but its real classification was unknown at the time, because numerous objects are emitting low energy X-rays in that particular region.
It turned out that the lower-energy X-ray emission from the object was a source first detected back in the 1970ѕ by NASA’s Einstein Observatory. Other spacecraft, such as the European Space Agency’s (ESA’s) XMM-Newton and NASA’s Chandra X-ray Observatory had also spotted it.
However, it wasn’t until the more recent observations from NuSTAR–along with hеlр derived frоm Swift ѕаtеllitе dаtа–thаt astronomers rеаlizеd that it wаѕ the same оbjесt as the theorized pulsar thаt emits the high-energy X-ray light of Andromeda.
Hungry black holes
Astronomers have long thought that voracious black holes, which are more massive than pulsars, usually dominate the high-energy X-ray light in galaxies. As a delectable banquet of shredded stars and clouds of gas spirals down, down, down into the greedy gravitational grip of the hungry black hole, then forming a bright surrounding structure called an accretion disk, this unfortunate material gets hotter and hotter and hotter, and the se extremely high temperatures emit high-energy radiation. The pulsar, which features a lower mass than any of Andromeda’s resident black holes, is brighter at great energies than the galaxy’s entire black hole population.
Andromeda is slightly larger than the Milky Way. It is close enough to us, for observers to see it without the aid of a telescope on clear, dark, starlit nights.