Messier 63 or M63, also known as NGC 5055 or the seldom-used Sunflower Galaxy, is a

spiral galaxy Spiral galaxies form a galaxy morphological classification, class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

Canes Venatici Canes Venatici ( ) is one of the 88 constellations designated by the International Astronomical Union (IAU). It is a small northern constellation that was created by Johannes Hevelius in the 17th century. Its name is Latin for 'hunting dogs', and ...

with approximately 400 billion stars. M63 was first discovered by the French astronomer

Pierre Méchain Pierre François André Méchain (; 16 August 1744 – 20 September 1804) was a French astronomer and surveyor who, with Charles Messier, was a major contributor to the early study of deep-sky objects and comets. Life Pierre Méchain was bo ...

, then later verified by his colleague

Charles Messier Charles Messier (; 26 June 1730 – 12 April 1817) was a French astronomer. He published an astronomical catalogue consisting of 110 nebulae and star clusters, which came to be known as the ''Messier objects'', referred to with th ...

on 14 June 1779. The galaxy became listed as object 63 in the

Messier Catalogue The Messier objects are a set of 110 astronomical objects catalogued by the French astronomer Charles Messier in his ' (''Catalogue of Nebulae and Star Clusters''). Because Messier was interested only in finding comets, he created a list of thos ...

. In the mid-19th century, Anglo-Irish astronomer Lord Rosse identified spiral structures within the galaxy, making this one of the first galaxies in which such structure was identified. The shape or morphology of this galaxy has a

classification Classification is the activity of assigning objects to some pre-existing classes or categories. This is distinct from the task of establishing the classes themselves (for example through cluster analysis). Examples include diagnostic tests, identif ...

of SAbc, indicating a spiral form with no central bar feature (SA) and moderate to loosely wound

arms Arms or ARMS may refer to: *Arm or arms, the upper limbs of the body Arm, Arms, or ARMS may also refer to: People * Ida A. T. Arms (1856–1931), American missionary-educator, temperance leader Coat of arms or weapons *Armaments or weapons **Fi ...

(bc). There is a general lack of large-scale continuous spiral structure in visible light, so it is considered a '' flocculent galaxy''. However, when observed in the

near infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those o ...

, a symmetric, two-arm structure is seen. Each arm wraps 150° around the galaxy and extends out to from the nucleus. M63 is a weakly

active galaxy An active galactic nucleus (AGN) is a compact region at the center of a galaxy that emits a significant amount of energy across the electromagnetic spectrum, with characteristics indicating that this luminosity is not produced by the stars. Such e ...

with a LINER nucleus – short for 'low-ionization nuclear emission-line region'. This displays as an unresolved source at the galactic nucleus that is cloaked in a diffuse

emission Emission may refer to: Chemical products * Emission of air pollutants, notably: ** Flue gas, gas exiting to the atmosphere via a flue ** Exhaust gas, flue gas generated by fuel combustion ** Emission of greenhouse gases, which absorb and emit rad ...

. The latter is extended along a

position angle In astronomy, position angle (usually abbreviated PA) is the convention for measuring angles on the sky. The International Astronomical Union defines it as the angle measured relative to the Celestial pole, north celestial pole (NCP), turning pos ...

of 110° relative to the

north celestial pole The north and south celestial poles are the two points in the sky where Earth's axis of rotation, indefinitely extended, intersects the celestial sphere. The north and south celestial poles appear permanently directly overhead to observers at ...

, and both

soft X-ray An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ran ...

s and hydrogen (

H-alpha Hydrogen-alpha, typically shortened to H-alpha or Hα, is a deep-red visible spectral line of the hydrogen atom with a wavelength of 656.28 nm in air and 656.46 nm in vacuum. It is the first spectral line in the Balmer series and is em ...

) emission can be observed coming from along nearly the same direction. The existence of a

supermassive black hole A supermassive black hole (SMBH or sometimes SBH) is the largest type of black hole, with its mass being on the order of hundreds of thousands, or millions to billions, of times the mass of the Sun (). Black holes are a class of astronomical ...

(SMBH) at the nucleus is uncertain; if it does exist, then the mass is estimated as , or around 850 million times the mass of the Sun. Radio observations at the 21-cm hydrogen line show the gaseous disk of M63 extends outward to a radius of , well past the bright optical disk. This gas shows a symmetrical form that is warped in a pronounced manner, starting at a radius of . The form suggests a

dark matter In astronomy, dark matter is an invisible and hypothetical form of matter that does not interact with light or other electromagnetic radiation. Dark matter is implied by gravity, gravitational effects that cannot be explained by general relat ...

halo that is offset with respect to the inner region. The reason for the warp is unclear, but the position angle points toward the smaller companion galaxy, UGC 8313. The distance to M63, based upon the luminosity-distance measurement is . The

radial velocity The radial velocity or line-of-sight velocity of a target with respect to an observer is the rate of change of the vector displacement between the two points. It is formulated as the vector projection of the target-observer relative velocity ...

relative to the

Local Group The Local Group is the galaxy group that includes the Milky Way, where Earth is located. It has a total diameter of roughly , and a total mass of the order of . It consists of two collections of galaxies in a " dumbbell" shape; the Milky Way ...

yields an estimate of . Estimates based on the

Tully–Fisher relation In astronomy, the Tully–Fisher relation (TFR) is a widely verified empirical relationship between the mass or intrinsic luminosity of a spiral galaxy and its asymptotic rotation velocity or emission line width. Since the observed brightness of ...

range over . The

tip of the red-giant branch Tip of the red-giant branch (TRGB) is a primary distance indicator used in astronomy. It uses the luminosity of the brightest red-giant-branch stars in a galaxy as a standard candle to gauge the distance to that galaxy. It has been used in conjun ...

technique gives a distance of . M63 is part of the

M51 Group The M51 Group is a group of galaxies located in Canes Venatici. The group is named after the brightest galaxy in the group, the Whirlpool Galaxy (M51A). Other notable members include the companion galaxy to the Whirlpool Galaxy ( M51B) and the ...

, a group of galaxies that also includes M51 (the 'Whirlpool Galaxy'). One

supernova A supernova (: supernovae or supernovas) is a powerful and luminous explosion of a star. A supernova occurs during the last stellar evolution, evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion ...

has been observed in M63: ( typeIa, mag. 11.8) was discovered by Glenn Jolly on 24 May 1971, and was discovered independently by Roger Clark on 29 May 1971. It reached peak light around 26 May. While the spectrum was consistent with a supernova of type I, the spectroscopic behavior appeared anomalous.

Gallery

File:Messier 63 GALEX WikiSky.jpg, M63 imaged in UV light by the

GALEX Galaxy Evolution Explorer (GALEX or Explorer 83 or SMEX-7) was a NASA orbiting space telescope designed to observe the universe in ultraviolet wavelengths to measure the history of star formation in the universe. In addition to paving the way ...

satellite. The UV light is produced primarily by young, massive stars, so the UV-bright areas are regions where stars are currently forming. Credit

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

/ WikiSky File:M63 3.6 8.0 24 microns spitzer.png, Messier 63 seen in the

infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those ...

by the

Spitzer Space Telescope The Spitzer Space Telescope, formerly the Space Infrared Telescope Facility (SIRTF), was an infrared space telescope launched in 2003, that was deactivated when operations ended on 30 January 2020. Spitzer was the third space telescope dedicate ...

. The infrared radiation traces the dust within the spiral arms, which does not radiate visible light. A small dust ring can be seen just outside of the galaxy's center. File:M63 Sunflower Galaxy.png, The Sunflower Galaxy M 63 taken in France by amateur astrophotographer Anthony MICHEL

References

External links

*
Sunflower Galaxy @ SEDS Messier pages

Sunflower Galaxy (M63) at Constellation Guide
{{DEFAULTSORT:Messier 63 Unbarred spiral galaxies LINER galaxies M51 Group Canes Venatici 063 NGC objects 08334 46153 Astronomical objects discovered in 1779 Discoveries by Pierre Méchain

Gallery

See also

References

External links