A new dwarf galaxy named Pisces VII / Triangulum III was discovered by amateur astronomer Giuseppe Donatiello using public image data from DESI Legacy Imaging Surveys.
The galaxy, located in the constellation Pisces, is three million light years distant from Earth and was later confirmed by an official observation using the Telescope Nazionale Galileo in Italy,
“I discovered it through visual inspection of public images from the DESI Legacy Survey, precisely to identify new satellites in the Andromeda system, outside of areas already investigated in the past”, Giuseppe Donatiello explained, indicating that he knew that the probability of finding something new “was real”.
This new finding could be an ultra-weak dwarf galaxy or the second known satellite of the Triangle galaxy.
“Theoretical knowledge about galaxy formation means that we would expect to see many more small galaxies orbiting the Triangulum galaxy.” said Emily Charles, a student in the Physics Department at the University of Surrey and co-author of the paper where Donatiello’s finding was confirmed.
“However, so far it only has one known satellite. If this newly identified galaxy belongs to the Triangle galaxy, it could imply that there are many more that have yet to be discovered, as they are too faint to appear in previous studies of the system.”, Highlights the scientist.
To confirm whether the new galaxy is isolated or a satellite of the Triangulum galaxy, astronomers must accurately measure the distance to the galaxy and see how it moves compared to its larger companion.
“The Triangle galaxy currently defies the assumptions of astrophysicists, but this new finding begins to reassure us that our theories are correct,” explains Charles.
To confirm this, more images are required using other telescopes.
“The deep images from Hubble would allow us to reach fainter stars that act as more robust distance estimators, since they have a standard brightness”, said Noushin Karim, a student in the Physics Department at the University of Surrey, who co-authored the study.
“To confirm the movement of the new galaxy, we need images from an 8 or 10 m telescope, such as Keck or Gemini”he adds.
Pisces VII / Triangulum III would be the fifth dwarf galaxy identified by the same amateur astronomer after those discovered in 2016 by Donatiello I and last year by Donatiello II, III and IV.