M87, also known as Virgo A or NGC 4486, is a giant elliptical galaxy that lies 15 million parsecs away (53 million light years) in the center of the Virgo Cluster. It is a super-giant D class galaxy with an elliptical nucleus and diffused envelope. It is located at the borders of the constellations Virgo and Coma Berenices, between the stars Epsilon Virginis and Denebola, and it is classified as an E0p (peculiar spherical) galaxy because of the presence of a relativistic jet coming out from its core. M87 forms the core of the Virgo Super Cluster, of which the local group (Milky Way, Andromeda and other galaxies) is a distant member.
History
M87 was discovered and cataloged as the 87th nebulous object by Charles Messier on March 18, 1781. In the same year, he also cataloged 103 nebulous objects, each of which uses the prefix “M” followed by a number, which corresponds to the order in which they were discovered. Many galaxies lie in the Virgo Cluster. In the late 1800s, M87 was included in the new general catalog as NGC 4486. The galaxy is categorized as an E0p galaxy, which is a designation given to an elliptical galaxy that shows a spherical shape. The “p”suffix stands for “peculiar,” that is to say, it does not fit into a classification of galaxies. The peculiarity is due to the presence of a relativistic jet at its core.
Features
M87 is about 120,000 light years across, and within its core resides a super-massive black hole from which a precise mass (6.6 billion solar masses) has been measured. From the black hole, an outburst of matter is emerging as a narrow beam of hot gas. This jet of gas is so bright that it even eclipses the M87’s bright core. This galaxy is a very strong source of gamma rays, which comprise one of the most energetic kinds of rays in the electromagnetic spectrum. These rays have been observed for over five years, and in 2006, scientists measured the fluctuation of rays, and they found out that it varies over a few days, suggesting that the source of rays could come from the area close to the black hole.
The unusual jet stream was discovered early in the 20th century. Although the exact cause of this jet is completely unknown, it is believed that it might be produced by energetic gas swirling around the massive black hole at the center of the galaxy. The energetic particles emerging from the black hole create an outburst of electrons ejected at nearly the speed of light and extending for approximately 1,500 parsecs (5,000 light years). The black hole at the center of M87 is the most massive, with about 6.6 billion solar masses. An approximate number of 12,000 globular clusters orbit around M87, compared with only 150-200 that orbit the Milky Way Galaxy.
Distance
M87 is located 55 million light years away from Earth in the Virgo Cluster, which is one of the most highly densed space regions in the near universe, with thousands of galaxies. Many techniques have been used to determine the distance of M87 to earth, including the measurement of luminosity of planetary nebulae, the linear distribution of globular clusters, calculating the distance using the Cepheid variable stars and utilizing individual red giant stars. All these measurements have provided an approximate distance of 16 million parsecs (55 million light years).
M87, the largest and most massive galaxy in the near universe, is believed to have been formed by the combining of hundreds of smaller galaxies. The black hole residing at the center of M87 is thought to be the first black hole the scientists are able to actually observe. Hubble telescope, with its high resolution, allows scientists to separate the jet from the black hole and observe it in the ultra-violet spectrum. According to the daily galaxy.com. Faint rings and plumes, extending away from the galaxy’s center, are evidences that repetitive outbursts from the core of the supermassive black hole have been affecting the galaxy for over a hundred million years.
