Sombrero Galaxy | Facts, Information, History & Definition

The Sombrero Galaxy, also designated as Messier 104, or NGC 4594, is a lenticular galaxy situated between the borders of the Virgo and Corvus constellations.

Key Facts & Summary

The Sombrero Galaxy is located at around 31.1 million light-years / 9.55 megaparsecs away from our Solar System.
This galaxy has a diameter of around 49,000 light-years, which is 30% of the size of our Milky Way Galaxy.
The Sombrero Galaxy has a very bright nucleus, an unusually large central bulge, and a prominent dust lane in its inclined disk.
This dark dust lane and the bulge is the reason for why Messier 104, is called the Sombrero Galaxy.
The Sombrero Galaxy has an absolute magnitude of -21.8, and an apparent magnitude of +8.0, making it easily visible with amateur telescopes.
Many consider the Sombrero Galaxy as the galaxy with the highest absolute magnitude within a radius of 10 megaparsecs of the Milky Way.
What attracts professional astronomers in this galaxy, is its large bulge, its central supermassive black hole, and its dust lane.
The Sombrero Galaxy was discovered in 1781 by astronomer Pierre Mechian.
This galaxy has a relatively large number of globular clusters, between 1,200 and 2,000.
The Sombrero galaxy lies within a complex, filament-like cloud of galaxies that extends south of the Virgo Cluster.
It is unclear if this galaxy is part of a formal galaxy group.
The Sombrero galaxy can be found 11.5^o west of the brightest star in the zodiacal constellation of Virgo, Spica / Alpha Virginis.
Another way to find the Sombrero Galaxy is to look at 5.5^o northeast of the sixth-brightest star in the constellation of Corvus, Eta Corvi.
The Sombrero Galaxy is visible in 7×35 binoculars or a 4-inch (100 mm) amateur telescope. An 8-inch (200 mm) telescope is needed to distinguish the bulge from the disk, and a 10- or 12- inch (250 to 300 mm) telescope is needed to see the dark dust lane.

The Sombrero Galaxy

The Sombrero Galaxy is a lenticular galaxy situated between the borders of the Virgo and Corvus constellations. It is also designated as Messier 104, NGC 4594, UGC 293, or PGC 42407.

The Sombrero Galaxy was first discovered by French astronomer Pierre Mechain, on the 11^th of May, 1781. He described the galaxy in a letter to J. Bernoulli, which was later published in the “Berliner Astronomiches Jahrbuch”.

Famous French astronomer Charles Messier made a hand-written note about this and five other objects, which are now collectively recognized as Messier 104 and Messier 109, in his list of objects now known as the Messier Catalogue. However, Messier 104 was not officially included in this list until 1921.

German astronomer William Herschel independently discovered the Sombrero Galaxy in 1784, and additionally noted the presence of a “dark stratum” in the galaxy’s disc, what is now called a dust lane. Later astronomers connected Pierre’s and Herschel’s observations.

In 1921, the Sombrero Galaxy was designated as a Messier object. The French astronomer, Camille Flammarion, found Messier’s personal list of the Messier objects, and this included his handwritten notes about the Sombrero Galaxy.

This galaxy was identified with the object 4594 in the New General Catalogue, and Flammarion declared that it should also be included in the Messier Catalogue. Since this time, the Sombrero Galaxy has been known as Messier 104 or M104.

Sombrero Galaxy – Dust Ring

The most striking feature of the Sombrero Galaxy is its dust lane which crosses in front of its bulge. This dust lane is a symmetrical ring that encloses the bulge of the galaxy.

Most of the cold atomic hydrogen gas and the dust of this galaxy, lies in this ring. This right might also contain most of the galaxy’s cold molecular gas. The Sombrero Galaxy’s dust ring is the primary site of its star formation.

Sombrero Galaxy – Nucleus

The nucleus of the Sombrero Galaxy is classified as a LINER – low-ionization nuclear emission-line region. These nuclear regions contain ionized gas, however, the ions are only weakly ionized – the atoms are missing a couple of electrons.

Some LINER nuclei may be powered by hot, young stars that are found in star-forming regions, while other LINER nuclei may be powered by active galactic nuclei, which usually contains a supermassive black hole.

Analysis of the Sombrero Galaxy’s nucleus revealed that it is most likely devoid of star formation regions, however, a supermassive black hole has been discovered in its nucleus, and it is probably the source that weakly ionizes the gas in the Sombrero Galaxy.

Sombrero Galaxy – Supermassive Black Hole

A supermassive black hole is present in the Sombrero Galaxy. This was discovered in the 1990s, when a group led John Kormendy demonstrated this.

The supermassive black hole in the Sombrero Galaxy is among the most massive black holes ever discovered in nearby galaxies, having around 1 billion times the mass of our Sun.

How to Find the Sombrero Galaxy, and Through Which Telescopes can it be Seen?

The Sombrero Galaxy is situated between the borders of the zodiacal constellation of Virgo, the celestial maiden, and Corvus, the celestial crow. It lies within a complex, filament-like cloud of galaxies that extends south of the Virgo Cluster.

The Sombrero galaxy can be found 11.5^o west of the brightest star in the zodiacal constellation of Virgo, Spica / Alpha Virginis. Another way to find the Sombrero Galaxy is to look at 5.5^o northeast of the sixth-brightest star in the constellation of Corvus, Eta Corvi.

Right Ascension – Sombrero Galaxy: 12^h 39^m 59.4^s
Declination – Sombrero Galaxy: -11^o 37’23’

The Sombrero Galaxy has an absolute magnitude of -21.8, and an apparent magnitude of +8.0, making it easily visible with amateur telescopes.

The Sombrero Galaxy is visible in 7×35 binoculars or a 4-inch (100 mm) amateur telescope. An 8-inch (200 mm) telescope is needed to distinguish the bulge from the disk, and a 10- or 12- inch (250 to 300 mm) telescope is needed to see the dark dust lane.

Why is the Sombrero Galaxy Called the Sombrero Galaxy?

The lenticular galaxy, Messier 104, is called the Sombrero Galaxy because it features a prominent dust lane in its inclined disk, and an unusually large central bulge, which gives this galaxy the appearance of a sombrero hat.

Distance, Contents, Size, and Other Characteristics of the Sombrero Galaxy

The Sombrero Galaxy is located at around 31.1 million light-years / 9.55 megaparsecs, away from our Solar System. It mostly resides in the zodiacal constellation of Virgo, between the borders with the constellation of Corvus, the celestial crow.

The Sombrero Galaxy has a diameter of around 49,000 light-years / 15 kiloparsecs, or 30% the size of our Milky Way galaxy. It has a bright nucleus, an unusually large central bulge, and a prominent dust lane in its inclined disk.

Image of the famous early-type spiral galaxy Messier 104, widely known as the “Sombrero” (the Mexican hat) because of its particular shape. The “Sombrero” is located in the constellation Virgo (The Virgin), at a distance of about 50 million light-years. Messier 104 is the 104th object in the famous catalogue of nebulae by French astronomer Charles Messier (1730 – 1817). It was not included in the first two editions (with 45 objects in 1774; 103 in 1781), but Messier soon thereafter added it by hand in his personal copy as a “very faint nebula”. The recession velocity, about 1000 km/sec, was first measured by American astronomer Vesto M. Slipher at the Lowell Observatory in 1912; he was also the first to detect the galaxy’s rotation. This galaxy is notable for its dominant nuclear bulge, composed primarily of mature stars, and its nearly edge-on disc composed of stars, gas, and intricately structured dust. The complexity of this dust, and the high resolution of this image, is most apparent directly in front of the bright nucleus, but is also very evident as dark absorbing lanes throughout the disc. A significant fraction of the galaxy disc is even visible on the far side of the source, despite its massive bulge. A large number of small and slightly diffuse sources can be seen as a swarm in the halo of Messier 104. Most of these are globular clusters, similar to those found in our own Galaxy This picture was obtained with FORS1 multi-mode instrument at VLT ANTU on January 30, 2000. It is a composite of three exposures in different wavebands. North is up and East is left. Technical informationÂ :Â This composite image is based on three exposures from the FORS1 instrument at VLT ANTU. They were obtained at about 6:20 hrs UT on January 30, 2000, through V-band (central wavelength 554 nm; 112 nm Full Width Half Maximum (FWHM); exposure time 120 sec; here rendered as blue), R-band (657 nm; 150 nm FWHM; 120 sec; green) and I-band (768 nm; 138 nm FWHM, 240 sec; red). The seeing was 0.6â¤?0.7 arcseconds. This image is available as a mounted image in the ESOshop. #L

This galaxy has a relatively large number of globular clusters, between 1,200 and 2,000. The ratio of the number of globular clusters to the total luminosity of the galaxy is high, at least in comparison to our Milky Way galaxy.

The primary site of star formation in the Sombrero Galaxy is thus in its dust ring/dust lane. Most of the cold atomic hydrogen gas and the dust of this galaxy lies in this ring. This right might also contain most of the galaxy’s cold molecular gas

Did you know?

In late 2009, an ultracompact dwarf galaxy was discovered accompanying the Sombrero Galaxy. This dwarf galaxy has an absolute magnitude of -12.3 and an effective radius of around 47.9 light-years.
The best time to observe the Sombrero Galaxy is during the month of May.
The Sombrero Galaxy is among the most massive objects located in the Virgo Cluster of galaxies.
The Sombrero Galaxy has around 100 billion stars.