​                                                                M82 - The Cigar Galaxy

 

    Discovered by Johann Elert Bode in 1774.

 

    Messier 82 (M82, NGC 3034) is a remarkable galaxy of peculiar type in constellation Ursa Major. It is usually classified as irregular, though probably a distorted disk galaxy, and famous for its heavy star-forming activity, thus a prototype member of the class of starbursting galaxies. Forming a most conspicuous physical pair with its neighbor, M81 (THE showpiece galaxies for many Northern hemispherers), this galaxy is the prototype of an irregular of the second type, i.e. a "disk" irregular. Its core seems to have suffered dramatically from a semi-recent close encounter with M81, being in a heavy starburst and displaying conspicuous dark lanes. This turbulent explosive gas flow is also a strong source of radio noise, discovered by Henbury Brown in 1953. The radio source was first called Ursa Major A (strongest radio source in UMa) and cataloged as 3C 231 in the Third Cambridge Catalogue of Radio Sources.

 

    In the infrared light, M82 is the brightest galaxy in the sky; it exhibits a so-called infrared excess (it is much brighter at infrared wavelengths than in the visible part of the spectrum). This behaviour can also be observed for the companion of M51, M51B (NGC 5195), and the peculiar galaxy NGC 5128 (Centaurus A). The visual appearance is that of a silvery sliver, as John Mallas decribed it.

 

    Recently, over 100 freshly-formed (young) globular clusters have been discovered with the Hubble Space Telescope. Their formation is probably another effect triggered by the encounter with M81. It was estimated that the most recent tidal encounter occurred between about 50 and several 100 million years ago: STScI's most recent number was 600 million years, when the 100-million-year-long period of heavier interaction began. As a member of the M81 group, M82 is 12 million light years distant. M82 was discovered on December 31, 1774 by Johann Elert Bode together with M81; he described it as a "nebulous patch", about 0.75 deg away from M81, which "is very pale and of elongated shape," and cataloged it as No. 18 in his catalog.

 

    Pierre Méchain independently rediscovered both galaxies as nebulous patches in August 1779 and reported them to Charles Messier, who added them to his catalog after his position measurement on February 9, 1781. M82 belongs to those few Messier objects which have been assigned a Herschel number, H IV.79, based on an observation of September 30, 1802, while William Herschel usually carefully avoided to give his numbers to Messier objects. William Parsons, the Third Earl of Rosse, was the first to remark on the dark dust lanes and patches visible in the central part of M82. Halton Arp has included M82 as No. 337 in his Catalogue of Peculiar Galaxies.

 

                                                                  Supernova SN2014J

 

    SN 2014J is a type-Ia supernova in Messier 82 (the 'Cigar Galaxy', M82) discovered in mid-January 2014. It is the closest type-Ia supernova discovered in the past 42 years. The supernova was discovered by astronomer Steve Fossey, of University College London. Fossey was training four undergraduate students (Ben Cooke, Guy Pollack, Matthew Wilde and Thomas Wright) to use a small 0.35-metre (14 in) telescope at University of London Observatory, located in Mill Hill, north London.

 

    The discovery was serendipitous, because Fossey was not searching for supernovae and wanted to take advantage of a short gap in the cloud cover. He later said that "The weather was closing in, with increasing cloud, so instead of the planned practical astronomy class, I gave the students an introductory demonstration of how to use the CCD camera on one of the observatory’s automated 0.35–metre telescopes."  At 19:20 GMT on 21 January 2014, Fossey and his students noticed a bright new star in their images of the galaxy Messier 82, also known as the Cigar Galaxy. After comparing their image to archival ones of the same galaxy, they used observations with a second telescope to eliminate the possibility of an instrumental artefact. Their discovery was reported to the International Astronomical Union's Central Bureau for Astronomical Telegrams, who confirmed that they were the first to spot the supernova and assigned it the name SN 2014J as the tenth supernova discovered in 2014.