Lurking close to the centre of the massive agglomeration of galaxies which straddle the boundary between Virgo and Coma Berenices lies a circular, ninth-magnitude spot of light seen through binoculars and a small telescope on the Virgo side of the border. Amid all the sparkling spiral galaxies this seemingly unremarkable object is in fact mighty Messier 87 (NGC 4486, Virgo A), a supergiant elliptical galaxy (class E0, most spherical rather than flattened) that’s the powerhouse, central galaxy of the Virgo Cluster.
Lying approximately 52 to 55 million light years away, the Virgo Cluster is home to over 150 major spiral and elliptical galaxies and more than 2,000 smaller galaxies
Messier 87 is a behemoth by any standard; it’s one of the most massive galaxies in the local Universe, spanning around 240,000 light years (studies suggest its tenuous outer regions may extend much further) and contains as many as ten times more stars than our own Milky Way Galaxy. It’s collection of some 12,000 globular clusters dwarfs our Galaxy’s comparatively meagre count of under 200! At its core lies a supermassive black hole that astronomer’s believe to be six and a half billion times the mass of the Sun and 38 billion kilometres (24 billion miles) across. Contemplate M87’s staggering and sobering statistics while you gaze upon it.
Perhaps M87’s most famous feature is a central jet blasting out at superluminal velocities from its core, powered the aforementioned black hole. Remarkably, amateur astronomers are able to image this! Professional astronomers know Messier 87 as Virgo A, it being the most powerful source of radio energy in the Virgo Cluster.
Around mid April, Messier 87 culminates at about midnight BST from London at an altitude of 50 degrees or so. It lie just above the confines of Virgo’s ‘bowl’ asterism; sweep for it roughly two degrees north of the mid-point of a line drawn between magnitude +2.8 Vindemiatrix (epsilon [e] Virginis) and magnitude +4.1 omicron (o) Virginis. Check out its position on our sky map on page XX.
Visually and electronically, Messier 87 is smooth and featureless, with an almost perfect spheroidal form. Peering through larger and larger telescopes won’t substantially alter this view, apart from expanding its apparent diameter which extends in amateur images to 7.2’ x 6.8’. With careful image processing, imagers should be able to tease out the relativistic jet.
Messier 87 is not the only massive elliptical galaxy in the Virgo Cluster that’s easily observed. Messier 84 and 86 lie around 1.5 degrees west-northwest form M87 and are located in Markarian’s Chain. This is of a line of at least eight galaxies that curves north and east from Messier 84 and 86, just inside Virgo, and extends for about 1.5 degrees to NGC 4477 in Coma Berenices. All of the ‘chain gang’ should be within range of a 150mm (six-inch) telescope.
Dominant at the western end of the chain are Messier 84 and 86, a pair of ninth-magnitude elliptical galaxies (classed as E1 and E3, respectively) lying around 17’ apart. The next two links in the chain, NGC 4435 and 4438 (also catalogued as Arp 120), the interacting ‘starburst’ pair known as ‘The Eyes’, are the most interesting. NGC 4435 is the smaller, more northerly galaxy of the pair, a barred lenticular that, shining at magnitude +10.8, is fainter than NGC 4438, its larger and much-disrupted neighbour (+10.0), though it exhibits a higher surface brightness.
Moving further north and east but staying in Virgo sees NGC 4461, a 4’ x 1’ eleventh-magnitude spiral, with NGC 4458, a smaller and round elliptical. The last links in the chain lie across the boundary in Coma. NGC 4473 is a magnitude +10.2 class E5 elliptical spanning 5’ x< 3’ and, finally, lying around 12’ north is magnitude +10.4 NGC 4477, another spiral which covers 4’ x 3’.