Hubble Space Telescope images of M84

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The Hubble Space Telescope was employed to investigate the central core of

the bright and large Virgo Cluster lenticular galaxy M84.

At left, an image is presented showing the inner nucleus of M84, exhibiting

conspicuous dark lanes; this image has been taken with the Wide Field

Planetary Camera 2 (WFPC2). The long blue frame marks the position where

a slit was layed over the very center of the galaxy (the bright dot), for

investigation with the Space Telescope Imaging Spectrograph (STIS), one of

the instruments newly installed at HST’s second servicing mission (STS-82,

Space Shuttle Discovery) in February 1997.

The STIS exposure on the right shows this slit as imaged by the spectrograph.

Shorter wavelengths are on the left, longer wavelengths to the right in this

image. Therefore, blueshifted light, emitted from gas approaching us, is

shown left of the mean bar, redshifted light from receding gas masses on the

right. STIS used the light of hydrogene, as well as nitrogene and sulfur ions

to obtain the data represented here. From the red and blue shift, the orbital

velocity of the gas around the central object can be calculated. From this

velocity, the mass of the central object follows. In case of the central

object of M84, 300 million solar masses are concentrated within a distance

of 26 light years from the galaxy’s center. It is widely believed that this

for a supermassive black hole.

The nucleus of M84 has previously been found to be an active emitter of

radio radiation.

Last Modification: 21 Jun 1998 22:10 MET