The prototypical Seyfert galaxy M77 in Cetus is the brightest (magnitude 9) and closest (about 45 million light-years) of its class. Seyfert galaxies are named after American astronomer Carl Seyfert, who in 1943 created an inventory of galaxies that every one have an exceptionally brilliant or starlike nucleus. Seyferts have a spectrum dominated by distinguished emission traces, which originate from interstellar fuel being heated close to the galaxy’s nucleus by a supermassive black hole.
In 2018, the Atacama Massive Millimeter/submillimeter Array (ALMA) in Chile imaged a 20-light-year-wide doughnut-shaped ring (or torus) of dust and fuel rotating round M77’s central black hole, which accommodates the mass of 15 million Suns. The torus seems barely uneven, and its rotation reveals extremely random movement. This implies the energetic galactic nucleus had a violent historical past, presumably together with a merger with a smaller galaxy.
Pierre Méchain found M77 on Oct. 29, 1780, and reported its place to Charles Messier. Messier noticed it as a “cluster of faint stars” with nebulosity, and William Parsons, Earl of Rosse, referred to as it a “blue” spiral nebula in 1848. Right this moment we all know M77 is a chaotic spiral galaxy with an infrared bar. Its brilliant internal disk rivals the Milky Way in dimension, and the galaxy additionally sports activities a fainter spiral skirt that will increase M77’s dimension to 170,000 light-years.
You’ll discover this Ninth-magnitude surprise 1° southeast of 4th-magnitude Delta (δ) Ceti, simply west of a Tenth-magnitude star (SAO 130073). The galaxy’s youthful internal area (consisting of tightly wrapped, knotty spirals close to the nucleus with two primary dust arms) will be considered via moderate-sized telescopes at 150x and larger. Its older, fainter outer area requires bigger telescopes. Astroimagers can seize its distinguished star-forming areas situated close to the boundary of the internal and outer areas.
The galaxy’s brightest star-forming areas have been spied in telescopes as small as 4 inches; this view in all probability led astronomers like Messier to mistake it as a cluster.
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