Scientists Discovered a Quasi-periodic Oscillation in a Galaxy


A team of astronomers from the Florida Institue of Technology utilized data from the Rossi X-ray Timing Explorer (RXTE) and made quite the discovery. 

According to the new finding, there is a quasi-periodic oscillation (QPO) in a galaxy dubbed NGC 4945. When X-ray light from a cosmic body flickers specific frequencies, the phenomenon is called QPO. 

It is said that QPOs occur when X-rays are sent near the inner edge of an accretion disk in which gas whirls onto a compact object, for example, a black hole. Here is what you need to know.

Galaxy NGC 4945 Features

NGC 4945, a barred spiral galaxy in the constellation Centaurus, is located approximately 11.7 million light-years away from our planet. Observations indicate that NGC 4945 is actually an active galaxy that might comprise a supermassive black hole.

Recently, a team of astronomers supervised by scientists Evan Smith has realized a quest for low-frequency (LF) QPOs, searching through archival data from RXTE, collected between 1996 and 2011. The satellite ran more than 500 surveys of NGC 4945’s active galactic nucleus (AGN) and discovered that it exhibits an LFQPO.

The Team’s Findings and Results

According to the team, the light curve from RXTE surveys in the 2-10 keV band displays a prominent LFQPO with a period of almost six weeks. The newly spotted oscillations are also detected near this period in other three sub-bands. 

The team also noted that possible explanations for the examined QPO in NGC 4945 include spin of the central compact object, Keplerian orbital motion of matter in the disk, and general relativistic effects. They added that the available data doesn’t allow them to pick the most plausible hypothesis. 

NGC 4945 is indeed one of the brightest Seyfert galaxies at 100 keV and has a total bolometric brightness of approximately 200 tredecillion erg/s. It also radiates at around 10 % of the Eddington luminosity. More research of NGC 4945 is undoubtedly needed.

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