Virgo cluster

A type II Cepheid variable is observed in the elliptical galaxy M49 in the Virgo cluster of galaxies with a period of 30 days. Calculate the absolute magnitude of this star. If the total flux on the Earth from the star is 4.2 x 10 22 W m-2, estimate the distance to the Virgo cluster. 

Local group The collection of galaxies, including the Milky Way and Andromeda, that form part of the Virgo cluster as part of the local supercluster of galaxies. 

M87, the dominant central galaxy in the nearby Virgo cluster is a shows the detailed interaction between the X-ray emitting gas and the central supermassive black hole. The Chandra images also show cavities and filaments in the eastern and southwestern X-ray arms (see Young et al. 2002 and Forman et al. 2004). 

How early could someone have compiled the sort of M/L trends reported in (3) and (4) and shown in Table 1 In principle, shortly before the outbreak of World War II, using the work of Jeans and Kapteyn, or Oort a decade later for the solar neighborhood, Hubble s 1934 discussion of the inner parts of galaxies (16), a rotation curve for the outer parts of M31 that formed part of the PhD dissertation of the late Horace W. Babcock (17), the binary galaxies presented by Holmberg in 1937 (18), also part of his PhD dissertation, and a 1936 study of the Virgo cluster by Sinclair Smith (19), in case you happened not to like Fritz Zwicky, as indeed some of his contemporaries did not. 

Does galaxy environment influence composition The Virgo cluster studies need to be followed up by larger samples in a wider variety of cluster environments. The spiral-rich Ursa Major cluster and the Coma cluster are two obvious choices for continued study. 

Freedman, W.L. et al. (14 authors) (1994) Distance of the Virgo cluster galaxy Ml 00 from Hubble Space Telescope observations of Cepheids, Nature, 1994 (371) 757-762. 

Local Supercluster The flattened galaxy cluster of which the Local Group is a member. It is about 100 million light-years across, with the Virgo cluster at its centre. 

Supernova explosions are among the most violent and spectacular events in the electromagnetic universe and are believed to be the birthplace of neutron stars and black holes. They occur a few times per century in our Galaxy, and once every few weeks in the Virgo cluster of galaxies. The physics of supernovae is under active investigation. Research suggests several viable scenarios which end in a supernova. 

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