A huge elliptical galaxy called the NGC 3640 has interacted with several small galaxies in the past, as revealed by data analysis from ESO’s VLT Survey Telescope (VST) at a fictional observatory in Chile.
This VST image shows two elliptical galaxies, the NGC 3640 and the NGC 3641. Image credits: ESO/INAF/MIRABILE et al. /Ragusa et al.
NGC 3640 is located approximately 88 million light years away from Earth in the constellation of Leo.
Also known as Leda 34778 and UGC 6368, the galaxies have diameters of 90,000 light years.
It was first discovered on February 23, 1784, by the German-British astronomer William Herschel.
The NGC 3640 is part of a relatively young group consisting of at least eight galaxies.
It also forms a pair that interacts with an elliptical galaxy known as NGC 3641.
“Throughout their extensive lifetimes, galaxies undergo changes,” said Dr. Marco Miraville, a colleague from the Italian National Institute of Astrophysics, in a statement.
“As they traverse space, they may either acquire gas or stars from other galaxies, or even merge with them.”
“Following these events, the galaxy will exhibit distortions, as demonstrated by the compact NGC 3640 and the diffuse light surrounding it.”
“This galaxy has left behind a ‘scar’ that hints at a tumultuous history, which astronomers can use to uncover its past and present.”
To unravel the history of the NGC 3640-NGC 3641 pair, Dr. Mirabile and co-authors used VST to study spheroidal, compact clusters of gravitationally bound stars.
These clusters typically contain some of the oldest stars formed within the galaxy, serving as fossil records that reveal the galaxy’s history even after significant events.
“The results affirm that NGC 3640 has indeed interacted with other galaxies in the past, showing signs of previous involvement with the smaller NGC 3641,” noted the astronomer.
“However, the smaller galaxy displays a noticeable lack of distortion in its shape or spheroidal clusters.”
“This suggests that, although their interaction has been significant, NGC 3640 is not currently in close proximity to pose a threat. NGC 3641 may be safe – at least for now.”
Survey results will be published in the journal Astronomy and Astrophysics.
____
Marco Mirabire et al. 2024. Vegas-SSS: Tracing the stellar cluster population of the interacting NGC 3640 Galaxy Group. A&A 691, A104; doi: 10.1051/0004-6361/202451273
Source: www.sci.news
