Observations shed more light on the star formation history of galaxy NGC 2915

Tomasz Nowakowski is a member of the physics.org community.

Astronomers from China used the Very Large Telescope to investigate a blue compact dwarf galaxy. The results of the study were published in a paper on arXiv.org.

Blue compact dwarfs are low-luminosity and low-metal content dwarfs. They are characterized by a compact optical appearance and H II- region-like spectrum.

One of the closestBCDs to Earth is NGC 2915, which is some 13.4 million light years away. The neutral atomic hydrogen (H I) gas content in the local universe is very high and very long. Most of the young stellar populations and regions of ionized atomic hydrogen are located in the center of the universe.

Although it is rich in gas, the star formation activity is not visible in the outer disk. The triggering mechanism of the star formation is not clear.

The researchers wrote in the paper that they performed a comprehensive analysis of deep VLT/MUSE integral field spectroscopic observations.

The most massive star cluster was formed a couple of billion years ago. The results show that the most recent bursty star formation took place around 50 million years ago and lasted for about 100 million years.

The most recent bursty star formation may have recurred for less than four times in different locations in the last billion years. The episodes were mostly confined to the central region of the galaxy.

The study found that the stellar disk of NGC 2915 has a relatively weak but significant rotation within the central 1,600 light years, and that it appears to be anti-parallel to the neutral H I disk. The recent episodes of bursty star formation have been caused by external gas.

More information: Yimeng Tang et al, Unveiling the Formation of NGC 2915 with MUSE: A Counterrotating Stellar Disk Embedded in a Disordered Gaseous Environment. arXiv:2210.06485v1 [astro-ph.GA], arxiv.org/abs/2210.06485

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