Messier 100

Messier 100 (also known as NGC 4321) is an example of a grand design[4] intermediate spiral galaxy located within the southern part of constellation Coma Berenices. It is one of the brightest and largest galaxies in the Virgo Cluster, located approximately 55 million light-years[3] distant from Earth and has a diameter of 167,000 light years and contains 1 trillion stars, roughly the size of the Milky Way. It was discovered by Pierre Méchain on March 15, 1781 and was subsequently entered in Messier's catalogue of nebulae and star clusters[5] after Charles Messier[6] made observations of his own on April 13, 1781. The galaxy was one of the first spiral galaxies[6] to be discovered, and was listed as one of fourteen spiral nebulae by Lord William Parsons of Rosse in 1850. Two satellite galaxies[7][8] named NGC 4323--connected with M100 by a bridge of luminous matter--and NGC 4328 surround M100.

Messier 100
Observation data (J2000 epoch)
ConstellationComa Berenices[1]
Right ascension 12h 22m 54.9s[2]
Declination+15° 49′ 21″[2]
Redshift1571 ± 1 km/s[2]
Distance55 Mly[3]
Group or clusterVirgo Cluster
Apparent magnitude (V)9.5[2]
Size167,000 ly (diameter)
Apparent size (V)7′.4 × 6′.3[2]
Other designations
NGC 4321

Early observations

After the discovery of M100 by Méchain, Charles Messier made observations of the galaxy depicting it as a nebula without a star. He pointed out that it was difficult[6] to recognize the nebula because of its faintness. William Herschel was able to identify a bright cluster of stars[6] within the nebula during observations he did before John Herschel expanded the findings in 1833. With the advent of better telescopes, John Herschel was able to see a round, brighter galaxy; however, he also mentioned that it was barely visible through clouds. William Henry Smyth[6] extended the studies of M100, detailing it as a pearly white nebula and pointing out diffuse spots.

Star formation

Messier 100 is considered a starburst galaxy[9] with the strongest star formation activity concentrated in its center, within a ring - actually two tightly wound spiral arms attached to a small nuclear bar[10] with a radius of 1 kilo-parsec – where star formation has been taking place since at least 500 million years ago in separate bursts.[11]

As usual on spiral galaxies of the Virgo Cluster, in the rest of the disk both star formation[12] and neutral hydrogen, of which M100 is deficient compared to isolated spiral galaxies of similar Hubble type,[13] are truncated within the galaxy's disk, which is caused by interactions with the intracluster medium of Virgo.


Five supernovae[4] have been identified in M100. In March 1901 the first supernova of M100 was found, SN 1901B,[4][14] a type I supernova found when magnitude 15.6 at a distance from its nucleus. SN 1914A[4][15] was then discovered in February to March 1914; its type was undeterminable but was found when magnitude 15.7 at some distance from the center. Observations of M100 from February 21, 1960 to June 17, 1960 led to the discovery of SN 1959E, another type I supernova,[4][16] with the faintest magnitude, 17.5, among the five found, at 58"E and 21"S from its nucleus. On April 15, 1979, the first type II supernova found in the M100 galaxy was discovered; however the star SN 1979C[4][17] faded quickly; later observations from x-ray to radio wavelengths revealed its remnant. The latest supernova was discovered February 7, 2006; the star SN 2006X[4][18] had a magnitude of 15.3 when discovered two weeks before fading to magnitude +17.


Messier 100 — Grand Design Splendour

Image from the FORS instrument on the Very Large Telescope

Core of Messier 100

Core of Messier 100 taken with the high-resolution channel of Hubble Space Telescope's Advanced Camera for Surveys.

HAWK-I Messier 100

Infrared light with the HAWK-I camera on ESO's Very Large Telescope.

1994-02-b-full jpg

Central region imaged by the Hubble Space Telescope

ESO- SN 2006X in Messier 100-Phot-08b-06

SN 2006X in Messier 100. Images by VIMOS (left) and FORS 1 (right).

M100 lo1
Messier 100

24-inch telescope on Mt. Lemmon, AZ.

Messier 100 galaxy Hubble

Hubble Space Telescope image processed by Judy Schmidt


  1. ^ R. W. Sinnott, ed. (1988). The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters by J. L. E. Dreyer. Sky Publishing Corporation/Cambridge University Press. ISBN 978-0-933346-51-2.
  2. ^ a b c d e f "NASA/IPAC Extragalactic Database". Results for NGC 4321. Retrieved 2006-08-31.
  3. ^ a b "Messier 100". Hearst Observatory. Retrieved 2010-02-23.
  4. ^ a b c d e f g "Messier 100". SEDS: Spiral Galaxy M100 (NGC 4321), type Sc, in Coma Berenices. Retrieved 2010-02-23.
  5. ^ "Catalog of Nebulae and Star Clusters". SEDS. Retrieved 2010-02-23.
  6. ^ a b c d e "Messier 100". SEDS: Observations and Descriptions. Retrieved 2010-02-23.
  7. ^ S. di Serego Alighieri; et al. (2007). "The HI content of Early-Type Galaxies from the ALFALFA survey I. Catalogued HI sources in the Virgo cluster". Astronomy and Astrophysics. 474 (3): 851–855. arXiv:0709.2096. Bibcode:2007A&A...474..851D. doi:10.1051/0004-6361:20078205.
  8. ^ "NGC 4323". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2010-02-23.
  9. ^ Wozniak, H.; Friedli, D.; Martinet, L.; Pfenniger, D. (1999). "Double-barred starburst galaxies viewed by ISOCAM". The Universe as Seen by ISO. 427: 989. Bibcode:1999ESASP.427..989W.
  10. ^ Sakamoto, Kazushi; Okumura, Sachiko; Minezaki, Takeo; Kobayashi, Yukiyasu; et al. (1995). "Bar-Driven Gas Structure and Star Formation in the Center of M100". The Astronomical Journal. 110 (3): 2075. Bibcode:1995AJ....110.2075S. doi:10.1086/117670.
  11. ^ Allard, E. L.; Knapen, J. H.; Peletier, R. F.; Sarzi, M. (2006). "The star formation history and evolution of the circumnuclear region of M100". Monthly Notices of the Royal Astronomical Society. 371 (3): 1087–1105. arXiv:astro-ph/0606490. Bibcode:2006MNRAS.371.1087A. doi:10.1111/j.1365-2966.2006.10751.x.
  12. ^ R. A. Koopmann; J. D. P. Kenney (2004). "Hα Morphologies and Environmental Effects in Virgo Cluster Spiral Galaxies". Astrophysical Journal. 613 (2): 866–885. arXiv:astro-ph/0406243. Bibcode:2004ApJ...613..866K. doi:10.1086/423191.
  13. ^ Chung, A.; Van Gorkom, J.H.; Kenney, J.F.P.; Crowl, Hugh; et al. (2009). "VLA Imaging of Virgo Spirals in Atomic Gas (VIVA). I. The Atlas and the H I Properties". The Astronomical Journal. 138 (6): 1741–1816. Bibcode:2009AJ....138.1741C. doi:10.1088/0004-6256/138/6/1741.
  14. ^ "SN 1901B". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2010-02-23.
  15. ^ "SN 1914A". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2010-02-23.
  16. ^ "SN 1959E". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2010-02-23.
  17. ^ "SN 1979C". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2010-02-23.
  18. ^ "SN 2006X". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2010-02-23.

External links

Coordinates: Sky map 12h 22m 54.9s, +15° 49′ 21″

Coma Berenices

Coma Berenices is an ancient asterism in the northern sky which has been defined as one of the 88 modern constellations. It is located in the fourth galactic quadrant, between Leo and Boötes, and is visible in both hemispheres. Its name means "Berenice's Hair" in Latin and refers to Queen Berenice II of Egypt, who sacrificed her long hair as a votive offering. It was introduced to Western astronomy during the third century BC by Conon of Samos and was further corroborated as a constellation by Gerardus Mercator and Tycho Brahe. Coma Berenices is the only modern constellation named for a historic person.

The constellation's major stars are Alpha Comae Berenices, Beta Comae Berenices and Gamma Comae Berenices. They form a 45-degree triangle, from which Berenice's imaginary tresses, formed by the Coma Star Cluster, hang. The constellation's brightest star is Beta Comae Berenices, a 4.2-magnitude main sequence star similar to the Sun. Coma Berenices contains the North Galactic Pole and one of the richest known galaxy clusters, the Coma Cluster, part of the Coma Supercluster. Galaxy Malin 1, in the constellation, is the first-known giant low-surface-brightness galaxy. Supernova SN 2005ap discovered in Coma Berenices is the second-brightest known, and SN 1940B was the first observed example of a type II supernova. The star FK Comae Berenices is the prototype of an eponymous class of variable stars. The constellation is the radiant of one meteor shower, Coma Berenicids, which has one of the fastest meteor speeds, up to 65 kilometres per second (40 mi/s).

History of supernova observation

The known history of supernova observation goes back to 185 AD, when supernova SN 185 appeared, the oldest appearance of a supernova recorded by humankind. Several additional supernovae within the Milky Way galaxy have been recorded since that time, with SN 1604 being the most recent supernova to be observed in this galaxy.Since the development of the telescope, the field of supernova discovery has expanded to other galaxies. These occurrences provide important information on the distances of galaxies. Successful models of supernova behavior have also been developed, and the role of supernovae in the star formation process is now increasingly understood.

List of NGC objects (4001–5000)

This is a list of NGC objects 4001–5000 from the New General Catalogue (NGC). The astronomical catalogue is composed mainly of star clusters, nebulae, and galaxies. Other objects in the catalogue can be found in the other subpages of the list of NGC objects.

The constellation information in these tables is taken from The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters by J. L. E. Dreyer, which was accessed using the "VizieR Service". Galaxy types are identified using the NASA/IPAC Extragalactic Database. The other data of these tables are from the SIMBAD Astronomical Database unless otherwise stated.


M100 or M-100 may refer to:

M-100 (Michigan highway), a north–south state trunkline highway in the U.S. state of Michigan

M-100 (rocket), a two-stage Soviet sounding rocket

M100, the magnetoencephalographic equivalent to the N100 large, negative-going evoked potential measured by electroencephalography

Messier 100, a grand design spiral galaxy

Miles Student (M.100), a lightweight trainer aircraft

Palm m100 series, a popular lower cost version of the Palm Pilot

M100 (New York City bus), a New York City Bus route in Manhattan

Effa M100, the Brazilian name for the Changhe Ideal automobile

M100, the second version of the Jeep trailer

M100 Elan, a model of the Lotus Elan automobile

Mercedes-Benz M100 engine, a 6.3/6.9 liter SOHC V8 automobile engine

TRS-80 Model 100, an early portable computerIn athletics:

Masters athletics, an age group for athletes aged 35+

Messier object

The Messier objects are a set of 110 astronomical objects cataloged by the French astronomer Charles Messier in his Catalogue des Nébuleuses et des Amas d'Étoiles ("Catalogue of Nebulae and Star Clusters").

Because Messier was interested in finding only comets, he created a list of non-comet objects that frustrated his hunt for them. The compilation of this list, in collaboration with his assistant Pierre Méchain, is known as the Messier catalogue. This catalogue of objects is one of the most famous lists of astronomical objects, and many Messier objects are still referenced by their Messier number.

The catalogue includes some astronomical objects that can be observed from Earth's Northern Hemisphere such as deep-sky objects, a characteristic which makes the Messier objects extremely popular targets for amateur astronomers.A preliminary version first appeared in the Memoirs of the French Academy of Sciences in 1771,

and the last item was added in 1966 by Kenneth Glyn Jones, based on Messier's observations.

The first version of Messier's catalogue contained 45 objects and was published in 1774 in the journal of the French Academy of Sciences in Paris. In addition to his own discoveries, this version included objects previously observed by other astronomers, with only 17 of the 45 objects being Messier's.

By 1780 the catalogue had increased to 80 objects. The final version of the catalogue containing 103 objects was published in 1781 in the Connaissance des Temps for the year 1784.

However, due to what was thought for a long time to be the incorrect addition of Messier 102, the total number remained 102. Other astronomers, using side notes in Messier's texts, eventually filled out the list up to 110 objects.The catalogue consists of a diverse range of astronomical objects, ranging from star clusters and nebulae to galaxies. For example, Messier 1 is a supernova remnant, known as the Crab Nebula, and the great spiral Andromeda Galaxy is M31. Many further inclusions followed in the next century when the first addition came from Nicolas Camille Flammarion in 1921, who added Messier 104 after finding Messier's side note in his 1781 edition exemplar of the catalogue. M105 to M107 were added by Helen Sawyer Hogg in 1947, M108 and M109 by Owen Gingerich in 1960, and M110 by Kenneth Glyn Jones in 1967.

NGC 4323

NGC 4323 is a lenticular or dwarf elliptical galaxy galaxy located about 52.5 million light-years away in the constellation Coma Berenices. It was discovered in 1882 by astronomer Wilhelm Tempel. It is a companion of Messier 100. It is also a member of the Virgo Cluster.

SN 1979C

SN 1979C was a supernova about 50 million light-years away in Messier 100, a spiral galaxy in the constellation Coma Berenices. The Type II supernova was discovered April 19, 1979 by Gus Johnson, a school teacher and amateur astronomer. This type of supernova is known as a core collapse and is the result of the internal collapse and violent explosion of a large star. A star must have at least 9 times the mass of the Sun in order to undergo this type of collapse. The star that resulted in this supernova was estimated to be in the range of 20 solar masses.On November 15, 2010 NASA announced that evidence of a black hole had been detected as a remnant of the supernova explosion. Scientists led by Dr. Dan Patnaude from the Harvard–Smithsonian Center for Astrophysics in Cambridge, MA evaluated data gathered between 1995 and 2007 from several space based observatories. NASA's Chandra X-ray Observatory, the Swift Gamma-Ray Burst Mission, as well as the European Space Agency's XMM-Newton, and Germany's ROSAT all participated in the examination.The researchers observed a steady source of X-rays and determined that it was likely that this was material being fed into the object either from the supernova or a binary companion. However, an alternative explanation would be that the X-ray emissions could be from the pulsar wind nebula from a rapidly spinning pulsar, similar to the one in the center of the Crab Nebula. These two ideas account for several types of known X-ray sources. In the case of black holes the material that falls into the black hole emits the X-rays and not the black hole itself. Gas is heated by the fall into the strong gravitational field.

SN 1979C has also been studied in the radio frequency spectrum. A light curve study was performed between 1985 and 1990 using the Very Large Array radio telescope in New Mexico.

SN 2006X

SN 2006X was a Type Ia supernova about 65 million light-years away in Messier 100, a spiral galaxy in the constellation Coma Berenices. The supernova was independently discovered in early February 2006 by Shoji Suzuki of Japan and Marco Migliardi of Italy.

SN 2006X is particularly significant because it is a Type Ia supernova. These supernovae are used for measuring distances, so observations of these supernovae in nearby galaxies are needed for calibration. SN 2006X is located in a well-studied galaxy, and it was discovered two weeks before its peak brightness, so it may be extraordinarily useful for understanding supernovae and for calibrating supernovae for distance measurements. It may even be possible to identify the progenitor of this supernova.


TheSkyNet (stylized theSkyNet) was an astronomy research project which used volunteer Internet-connected computers to carry out research in astronomy. It was an initiative of the International Centre for Radio Astronomy Research (ICRAR), a joint venture of Curtin University and the University of Western Australia. TheSkyNet had two projects, Sourcefinder and POGS. Both projects have completed. TheSkyNet Sourcefinder aimed to test and refine automatic radio sourcefinding algorithms in preparation for radio galaxy surveys using the Australian Square Kilometre Array Pathfinder and the Square Kilometre Array. TheSkyNet POGS used Spectral Energy Distribution fitting to calculate characteristics of many galaxies using images taken by the Pan-STARRS PS1 optical telescope in Hawaii.

Virgo Cluster

The Virgo Cluster is a cluster of galaxies whose center is 53.8 ± 0.3 Mly (16.5 ± 0.1 Mpc)

away in the constellation Virgo. Comprising approximately 1300 (and possibly up to 2000) member galaxies, the cluster forms the heart of the larger Virgo Supercluster, of which the Local Group (containing our Milky Way galaxy) is a member. The Local Group actually experiences the mass of the Virgo Supercluster as the Virgocentric flow. It is estimated that the Virgo Cluster's mass is 1.2×1015 M☉ out to 8 degrees of the cluster's center or a radius of about 2.2 Mpc.Many of the brighter galaxies in this cluster, including the giant elliptical galaxy Messier 87, were discovered in the late 1770s and early 1780s and subsequently included in Charles Messier's catalogue of non-cometary fuzzy objects. Described by Messier as nebulae without stars, their true nature was not recognized until the 1920s.The cluster subtends a maximum arc of approximately 8 degrees centered in the constellation Virgo. Although some of the cluster's most prominent members can be seen with smaller instruments, a 6-inch telescope will reveal about 160 of the cluster's galaxies on a clear night. Its brightest member is the elliptical galaxy Messier 49; however its most famous member is the elliptical galaxy Messier 87, which is located in the center of the cluster.

Visible Multi Object Spectrograph

The Visible Multi-Object Spectrograph (VIMOS) is a wide field imager and a multi-object spectrograph installed at the European Southern Observatory's Very Large Telescope (VLT), in Chile. The instrument used for deep astronomical surveys delivers visible images and spectra of up to 1,000 galaxies at a time.The Franco-Italian instrument operates in the visible part of the spectrum from 360 to 1000 nanometers (nm). In the conceptual design phase, the multi-object spectrograph then called VIRMOS included an additional instrument, NIMOS, operating in the near-infrared spectrum of 1100–1800 nm.Operating in the three different observation modes, direct imaging, multi-slit spectroscopy, and integral field spectroscopy, the main objective of the instrument is to study the early universe through massive redshift surveys, such as the VIMOS-VLT Deep Survey.VIMOS saw its first light on 26 February, 2002, and has since been mounted on the Nasmyth B focus of VLT's Melipal unit telescope (UT3).

Wide Field and Planetary Camera

The Wide Field/Planetary Camera (WFPC) (pronounced as wiffpick (Operators of the WFPC1 were known as "whiff-pickers")) was a camera installed on the Hubble Space Telescope until December 1993. It was one of the instruments on Hubble at launch, but its functionality was severely impaired by the defects of the main mirror optics which afflicted the telescope. However, it produced uniquely valuable high resolution images of relatively bright astronomical objects, allowing for a number of discoveries to be made by HST even in its aberrated condition.

WFPC was proposed by James A. Westphal, a professor of planetary science at Caltech, and was designed, constructed, and managed by JPL. At the time it was proposed, 1976, CCDs had barely been used for astronomical imaging, though the first KH-11 KENNEN reconnaissance satellite equipped with CCDs for imaging was launched in December 1976. The high sensitivity offered such promise that many astronomers strongly argued that CCDs should be considered for Hubble Space Telescope instrumentation.

This first WFPC consisted of two separate cameras, each comprising 4 800x800 pixel Texas Instruments CCDs arranged to cover a contiguous field of view. The Wide Field camera had a 0.1 arcsecond pixel scale and was intended for the panoramic observations of faint sources at the cost of angular resolution. The Planetary Camera had a 0.043 arcsecond pixel scale and was intended for high-resolution observations. Selection between the two cameras was done with a four-facetted pyramid that rotated by 45 degrees.As part of the corrective service mission (STS-61 in December 1993) the WFPC was swapped out for a replacement version. The Wide Field and Planetary Camera 2 improved on its predecessor and incorporated corrective optics needed to overcome the main mirror defect. To avoid potential confusion, the WFPC is now most commonly referred to as WFPC1.

On its return to Earth, the WFPC was disassembled and parts of it were used in Wide Field Camera 3, which was installed in Hubble on May 14, 2009 as part of Servicing Mission 4, replacing WFPC2.

See also

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