Astronomers using the Multi Unit Spectroscopic Explorer (MUSE) instrument on ESO’s Very Large Telescope (VLT) have performed spectroscopic observations of the nearby galaxy system Markarian 739.
This image shows Markarian 739, a pair of merging galaxies some 425 million light-years away in the constellation of Leo. Image credit: ESO / Tubín et al., doi: 10.3847/1538-4357/abedba.
Markarian 739 lies approximately 425 million light-years away in the constellation of Leo.
Also known as Mrk 739, NGC 3758 and LEDA 35905, the galaxy system has a pair of bright cores.
Only about 11,000 light-years separate the two cores, each of which contains an active supermassive black hole gorging on infalling gas.
“This friendly-looking object is the result of two galaxies — known as Mrk 739W and Mrk 739E — merging into one another, complete with a pair of eyes hiding two growing supermassive black holes and a swirling grin,” said Dusán Tubín, a student at the Pontificia Universidad Católica de Chile, and his colleagues from the United States, Italy and Chile.
“Such mergers are rare in our galactic neighborhood,” they added.
“Mrk 739 is close enough (astronomically speaking) to study the event in detail, and thus gain a better understanding of the dramatic processes that take place during these cosmic mergers.”
By using the MUSE instrument on VLT, the team was able to study the effects of both the merger and the radiation emitted by the growing gigantic black holes.
Their study answered questions about the motion of Mrk 739W and Mrk 739E, the age of their stars, and the elements they are made up of.
They also found that Mrk 739E is much older than its companion, and that their merging process is at an early stage.
“The morphology and dynamics of the system are consistent with an early stage of the collision, where the foreground galaxy, Mrk 739W, is a young star-forming galaxy in an ongoing first passage with its background companion, Mrk 739E,” the authors said.
“Since the supermassive black hole in Mrk 739W does not show evidence of being rapidly accreting, we claim that the northern spiral arms of Mrk 739W are ionized by the nuclear activity of Mrk 739E.”
The findings were published in the Astrophysical Journal.
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Dusán Tubín et al. 2021. The Complex Gaseous and Stellar Environments of the Nearby Dual Active Galactic Nucleus Mrk 739. ApJ 911, 100; doi: 10.3847/1538-4357/abedba
