Astronomers have made comprehensive multi-wavelength observations of the large, massive spiral galaxy UGC 2885 using the Canada-Franco-Hawaii CFHT telescope. The results of the observing campaign, published on the arXiv preprint server, provide more detailed information about the properties of this galaxy.

UGC 2885, also known as the Ruby Galaxy, is a barred spiral galaxy located approximately 232 million light-years away in the constellation Perseus. With an estimated radius of approximately 400,000 light-years and a total mass of 1.5 trillion solar masses, it is one of the largest and most powerful galaxies in the local universe.

Previous observations of UGC 2885 had shown it to have a solid spiral structure, which is unusual for such a large and massive object. This galaxy in particular exhibits an almost perfect structure of spiral arms and disk, and no tidal tails. Moreover, unlike other large spiral galaxies, the star formation rate of UGC 2885 is approximately 2.47 solar masses per year.

These unusual features of UGC 2885 raise questions about its evolution, and a team of astronomers led by Matheus C. Carval of the University of Western Ontario in Canada decided to investigate it with the SITELLE CFHT spectrograph. “Our goal is to understand whether UGC 2885 follows the same evolutionary path as other large galaxies by examining its elemental metallicity ratio and place in the main sequence of star formation,” the researchers said.

The study found that UGC 2885 has a spherical metallicity of approximately 9.0 and is uniform within 0.3 dex over a wide radial spread in this galaxy. This places UGC 2885 in the high metallicity regime, corresponding to a large stellar mass measured at approximately 483 billion solar masses.

The data collected shows that UGC 2885 has an integrated mass of molecular hydrogen of 189 trillion solar masses. The galaxy also has an extreme molecular-to-stellar mass ratio of around -0.41. However, the mechanisms that could add cold gas to UGC 2885 are still unknown; because it is a completely isolated galaxy with no companions or any significant recent merger events.

It was also found that UGC 2885 has an average star formation rate of approximately 1.63 solar masses per year. This is a low value compared to known superspiral galaxies.

According to the authors of the paper, the results show that UGC 2885 went through several cycles of star formation, which increased its stellar mass and metallicity to its current state. However, the researchers found no evidence of any significant recent star formation or merger events.