Hubble Space Telescope images of M84


Also available as hi-res image

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 hydrogen, as well as nitrogen 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 massive central object is a candidate for a supermassive black hole.

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

(From: STScI-PRC97-12)

Hartmut Frommert
Christine Kronberg

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Last Modification: June 21, 1998