Five new dwarf galaxies detected around M63

Using an amateur telescope with an aperture of 0.14m, the astronomers observed a nearby spiral galaxy known as M63 (or NGC 5055). The observations identified the presence of five faint dwarf galaxies around M63 and allowed the researchers to determine their basic parameters. The discovery is reported in a document published November 10 on arXiv.org.

Dwarf galaxies, containing up to several billion stars, are difficult to detect due to their low brightness, low mass and small size. Astronomers usually find them as companions to larger galaxies. The large galaxies observed today are assumed to have formed from collisions of dwarf galaxies or from larger galaxies that attract material away from these dwarfs.

At a distance of about 29.3 million light-years, M63, nicknamed the “Sunflower Galaxy”, is a large spiral galaxy with no central bar and moderate to wide coiled arms. Previous observations of M63 have discovered the presence of multiple arcs and “plumes” of low surface brightness at its periphery. This very weak flux system is presumed to be the result of the accretion of a nano satellite over the past billion years.

To date, several dwarf galaxies have been detected in the vicinity of M63 that could be satellites of this galaxy. Now, a team of astronomers led by Igor Karachentsev of the Special Astrophysical Observatory (SAO) in Russia has added more objects to this list. Inspecting an image obtained with the TEC140ED APO refractor with 0.14m aperture with focal ratio f / 7 using a Moravian G3-16200 Monochrom CCD camera (KAF-16200), they found five new candidates for the M63 satellites with surface brightness very low.

“We present a deep image (50 hours of exposure) of the nearby spiral galaxy M63 (NGC 5055), taken with a telescope with an aperture of 0.14 m. (…) We found five dwarf galaxies with very low surface brightness around M63, “the astronomers wrote in the paper.

Recently discovered dwarf galaxies have received TBGdw3 to TBGdw7 designations. The median absolute magnitude B of these galaxies is –8.8 mag and they have a median surface brightness of approximately 27.8 mag / sq m. arcsec.

The two largest objects are TBGdw7 and TBGdw3, with a maximum angular diameter of approximately 21.7 and 21.6 arcmin. The smallest is TBGdw6, as it has a maximum angular diameter of approximately 18.5 arcmin. The astronomers added that the state of TBGdw6’s dwarf galaxy needs further confirmation as there is a possibility that it may be a patch of reflective nebulae.

TBGdw5 is the closest dwarf to M63, with a projected linear separation of approximately 283,600 light-years from this galaxy. The furthest from M63 was found to be TBGdw4 – the separation is approximately 394,500 light years.

Furthermore, the orbital mass of the halo M63 has been estimated at around 510 billion solar masses. It was also found that M63 has a low ratio of total mass to stellar luminosity since it was calculated to be around 4.8. This value is about six times lower than the respective ratio for our Milky Way galaxy and M 31.

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