Who discovered Messier 87

M 87

Elliptical Galaxy M 87 (NGC 4486)

in the virgin, Virgo A

The giant elliptical galaxy M 87, also called Virgo A, is one of the most remarkable objects in the sky. It is probably the dominant galaxy in the next big cluster, the famous Virgo cluster of galaxies (sometimes you can also find the name "Coma-Virgo cluster", which does justice to the location, as this cluster extends into the constellation Coma Berenice) . The distance to this galaxy, like the distance to this cluster, is given as 60 million light years.

The diameter of M87 of 7 arc minutes corresponds to a linear extension of 120,000 light years - that is well above the diameter of our galaxy. However, M87 is an elliptical galaxy of type E1 (some sources indicate type E0); it fills a much larger volume and therefore contains considerably more stars (and thus mass) than our galaxy, certainly a few trillion solar masses (J.C. Brandt and R.G. Roosen estimated a value of 2.7 trillion). It also has an extremely high luminosity with an absolute brightness of -22 magnitudes.

M 87 is famous for two peculiar and perhaps unique properties: on long-exposure images (like our picture) one found a huge system of globular clusters and a spectacular one jetwhich can be seen better on shorter-exposure photos.

This fascinating galaxy is perhaps the one with the most famous globular clusters. Several thousand (definitely more than 4000) are in orbit around this galaxy, forming a striking halo. The many satellites globular clusters of M87 can be seen in this picture as well as in the AAT pictures of M87.

The giant jet was launched in 1918 by H.D. Curtis discovered at the Lick Observatory. This phenomenon extends for thousands of light years (sources indicate 5000, but because the distance is often assumed to be too low, this value may be higher; the current author estimates that a value of 7-8000 would be more likely). This jet is made up of gaseous material ejected from the core of the galaxy. Polarimetric images of this jet have shown that its light has a strong polarization, as is typical for synchrotron radiation; you can also see it on (briefly exposed) photos (as in J.D. Wray's Color Atlas of Galaxies) see.
It shows violent turbulence; Observations have shown an apparently (!) Faster than light movement of gas clouds in this object - possibly a fake, since the direction of this jet points to us.

Simply gorgeous details of the M87's jet can be seen in this HST image edited by R. Mark Elowitz. Obviously, it can be broken down into a series of little knots and clouds, a fact that was reported in 1977 by H.C. Arp by Mt. Palomar and J. Lorre of JPL (according to Burnham). Already earlier (1966) Arp discovered a second jet that points in the opposite direction and is nowhere near as conspicuous.

M87 was also identified in 1954 by W. Baade and R. Minkowski as the strong radio source Virgo A (the strongest radio source in the constellation of Virgo). Two years later, in 1956, J.E. Baldwin and F.G. Smith (both working in Cambridge) found a weaker radio halo. This also turned out to be a powerful source of X-rays; it is located near the center of a cloud that emits hard X-rays and extends well over the Virgo Cluster.

Obviously, an object as interesting as M87 is being studied extensively with the Hubble Space Telescope. In the Hubble Space Telescope images from M87, the highly active core of this galaxy could be seen much more closely and they revealed a massive dark object of about 2 to 3 billion solar masses, which are concentrated inside within a radius of only 60 light years. This dark object is surrounded by a rapidly rotating accretion disk made of gas. The gas is possibly part of a larger system of interstellar matter discovered in 1990 by Fabry-Perot interferometry by astronomers at the Calar Alto Observatory.

The only supernova observed in M87 appeared in February 1919, but was not discovered on the photographic plates until 1922 by I. Balanowski, who estimated its maximum brightness to be 11.5 mag. If the distance from M87 is taken into account, this corresponds to an absolute brightness of approximately -20 magnitudes.

Right ascension12: 28.3 (hours: minutes)
declination+12: 40 (degrees: minutes)
distance60000.0 (* 1000 light years)
Visual brightness 9.2

| SEDS | Messier Home | M 86 | M 88 | -> star cluster | -> fog | -> galaxy | Indexes | Icons |

Updated by:
Hartmut Frommert ([email protected])
Translated by:
C. Kronberg --- 96/07/05 --- [email protected]