While analyzing data from the Dark Energy Camera Legacy Survey (DECaLS), astronomers at Christ University in Bangalore, India, accidentally discovered a new ring galaxy, designated DES J024008.08-551047.5, which may belong to a rare class of galaxies. polar ring galaxies. The discovery was reported in an article posted on the prepress server Aug. arXiv.

Systems called polar ring galaxies (PRGs) are systems that consist of an S0-like galaxy and a polar ring that has been separated for billions of years. Generally, these outer polar rings of gas and stars are oriented roughly perpendicular to the major axis of the central main galaxy.

However, although more than 400 candidate galaxies have been identified in PRG to date, only dozens of them have been confirmed as true polar ring galaxies by further spectroscopic observations. Now a team of astronomers led by Akhil Krishna has identified another PRG candidate. The discovery of DES J024008.08-551047.5 (or DJ0240) was made during visual observation of optical image data from DECaLS.

“We identified DJ0240 as a potential PRG candidate with a ring component nearly perpendicular to the host galaxy,” the researchers wrote in the paper.

The study found that DJ0240 has a ring nearly perpendicular to the main galaxy. The position angle of the ring is about 80 degrees, and the position angle of the host is about 10 degrees; this indicates that the two components are almost perpendicular to each other. The distance of the galaxy is estimated to be about 1.8 billion light years.

After analyzing the image, the team found that the ring is three times larger than the main galaxy, which consists of a bulge and a disk. Additionally, the ring commonly seen in other known PRGs appears to be bluer than the host. The authors of the paper explained that the presence of blue ring components in PRGs indicates a higher level of ongoing star formation activity in these structures.

The researchers found that DJ0240’s ring has a relatively small Sérsic index, further supporting the PRG classification of this galaxy. They added that the measured effective radii of galaxy components are comparable to those of other PRGs.

In summary, the astronomers concluded that DJ0240 was most likely a PRG and ruled out the possibility that its host galaxy was lenticular. However, more research is needed to reach firm conclusions.

“We propose that the ring galaxy DJ0240 is a promising candidate for inclusion in the PRG catalogue. However, further work is needed to confirm its classification as PRG, using spectroscopic observations, specifically to analyze the kinematic properties of both the main galaxy and the polar galaxy. ‘, the researchers write. Source