Andromeda (Credits: NASA/JPL-Caltech/GSFC)
While everyone else was making popcorn garlands and giving sentimental presents and eating marshmallow candies shaped like Santa, astronomers were busy too…busy scanning the Andromeda galaxy with a super powerful x-ray telescope array in space! (Yeah, that’s right, astronomers are no joke, boy!) According to NASA’s mission overview, “The NuSTAR instrument consists of two co-aligned grazing incidence telescopes with specially coated optics and newly developed detectors that extend sensitivity to higher energies as compared to previous missions such as Chandra and XMM. After launching into orbit on a small rocket, the NuSTAR telescope extends to achieve a 10-meter focal length. The observatory will provide a combination of sensitivity, spatial, and spectral resolution factors of 10 to 100 improved over previous missions that have operated at these X-ray energies.”
The astronomers operating this device (devices?) chose to look at Andromeda (AKA M31) the Milky Way’s big sister galaxy which is located relatively close by in galactic terms…a mere 2.5 million light years away. They wished to observe X-ray binary systems–disturbing star systems where a supermassive star collapsed either into a black hole or a neutron star. The huge mass left over from such a collapse plays havoc with the remaining living star. Frequently great plumes of matter are stripped away from the living star into the gravity well of the white dwarf or the black hole. As star stuff falls into the massive stellar fragment it produces large amounts of exotic radiation like x-rays.
Astronomers hope that by determining which of these systems harbor black holes versus neutron stars, they can find out more about such systems, which are theorized to have played a critical role in heating the interstellar gas nebulae which gave birth to the galaxies.
NuSTAR X-Ray Observatory (NASA)