January 01, 2018

Andromeda's Bright X-Ray Mystery Solved by NuSTAR

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-Elizabeth Landau

Andromeda is the nearest large galaxy to the Milky Way, and it is a spiral galaxy slightly larger than the Milky Way. It resides 2.5 million light-years from our own galaxy, which is considered very close, given the broader scale of the universe. Stargazers can see Andromeda without a telescope on dark, clear nights. It features a dominant source of high-energy X-ray emission. NASA's NuSTAR (Nuclear Spectroscopic Telescope Array) mission has pinpointed an object responsible for this high-energy radiation, but its identity was mysterious until now. The object, called Swift J0042.6+4112, is a possible pulsar. Its spectrum is very similar to known pulsars in the Milky Way, and It is likely in a binary system, in which material from a stellar companion gets pulled onto the pulsar, spewing high-energy radiation as the material heats up.

Many differences of the object from various spacecraft that brings researchers to observers deeply. In 2013, NASA's Swift satellite reported it as a high-energy source, but its classification was unknown, as there are many objects emitting low energy X-rays in the region. Other spacecraft, such as NASA's Chandra X-ray Observatory and ESA's XMM-Newton had also detected it. However, it wasn't until the new study by NuSTAR, aided by supporting Swift satellite data, that researchers realized it was the same object as this likely pulsar that dominates the high energy X-ray light of Andromeda.

"NuSTAR has made us realize the general importance of pulsar systems as X-ray-emitting components of galaxies, and the possibility that the high energy X-ray light of Andromeda is dominated by a single pulsar system only adds to this emerging picture," said Ann Hornschemeier, co-author of the study and based at NASA's Goddard Space Flight Center, Greenbelt, Maryland.

by Dini Dwintika Karuniati
16611042

2017-12-30 14:28:43.296000

Science Article

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