Themorphological classification of NGC 1068 in theDe Vaucouleurs system is (R)SA(rs)b,[5] where the '(R)' indicates an outer ring-like structure, 'SA' denotes a non-barred spiral, '(rs)' means a transitional inner ring/spiral structure, and 'b' says the spiral arms are moderately wound.[9] Annet al. (2015) gave it a class of SAa,[10] suggesting tightly wound arms. However,infrared images of the inner part of the galaxy reveal a prominent bar not seen in visual light,[11] and for this reason it is now considered a barred spiral.[12] Messier 77 is the largest member of a small group of galaxies,[13] which includesNGC 1055, an edge-on spiral galaxy likely twisted by gravitational interactions with Messier 77, and five small irregular galaxies.[14]
Messier 77 is anactive galaxy with anactive galactic nucleus (AGN), which is obscured from view by astronomical dust at visible wavelengths. The diameter of the molecular disk and hot plasma associated with the obscuring material was first measured at radio wavelengths by theVLBA andVLA. The hot dust around the nucleus was subsequently measured in the mid-infrared by theMIDI instrument at theVLTI. It is the brightest[15] and one of the closest and best-studied[12] type 2Seyfert galaxies,[3] forming a prototype of this class.[12]
Messier 77 is of key interest to scientists do to its relative proximity andluminosity, allowing for study of itsactive galactic nucleus.[16] This section contains relevant scientific discoveries that have been made as a result of studying M77.
It has been proposed that type 2 Seyfert galaxies are the same class of object as type 1 Seyfert galaxies, viewed from such an angle that the type 1 core is hidden from view.[17] An analysis of NGC 1068's spectra usinginterferometry by Tacconi et al. (1994) suggested that the galaxy's Seyfert 1 core was obstructed by a thickmolecular cloud region.[18]
X-ray source 1H 0244+001 in Cetus has been identified as Messier 77.[19]
It has a radio jet consisting of a northeast and a southwest region, caused by interactions with the interstellar medium.[20]The presence of bow shocks in the northeast region due to these interactions overlap with the edges of molecular outflow, suggesting that the jet is responsible for the outflow.[21]
In November 2022, theIceCube collaboration announced the detection of aneutrino source emitted by the active galactic nucleus of Messier 77.[24][25] It is the second detection by IceCube afterTXS 0506+056, and only the fourth known source includingSN1987A andsolar neutrinos. A potential candidate for the source of these neutrinos is the magnetic corona surrounding the active galactic nucleus, providing powerful enough particle acceleration to cause neutron radiation phenomena.[26]
^Thronson, Harley A. Jr.; et al. (1 August 1989), "Near-infrared image of NGC 1068 - Bar-driven star formation and the circumnuclear composition",Astrophysical Journal, Part 1,343:158–168,Bibcode:1989ApJ...343..158T,doi:10.1086/167693.
^abcAlexander, Tal; Lutz, Dieter; Sturm, Eckhard; Genzel, Reinhard; Sternberg, Amiel; Netzer, Hagai (June 2000), "Infrared Spectroscopy of NGC 1068: Probing the Obscured Ionizing AGN Continuum",The Astrophysical Journal,536 (2):710–717,arXiv:astro-ph/0002107,Bibcode:2000ApJ...536..710A,doi:10.1086/308973,S2CID15617708.
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![M77 imaged by ESO’s Very Large Telescope (VLT)[29]](/mt/?noimg=&dark=on&url=http%3a%2f%2fwww.wikipedia.org%2fwiki%2fFile%3aDazzling_galaxy_Messier_77.jpg)
