Tidal Interactions in M81 Group

This pair of images illustrates the need to study celestial objects at different wavelengths in order to get "the whole picture" of what is happening with those objects. At left, you see a visible-light image of the M81 Group of galaxies (from the Digital Sky Survey), shown in a reversed greyscale (dark regions are brighter). Most of the light in this image comes from stars in the galaxies. At right, a radio image, made with the VLA, shows the hydrogen gas, including streamers of gas connecting the galaxies. From the radio image, it becomes apparent that this is an interacting group of galaxies, not isolated objects.

The HI observations consist of a 12-pointing mosaic with the VLA in its most compact D-array configuration.

Legacy Astronomical Images

NRAO/AUI/NSF does not hold full copyright for this image. Contact the archivist for details.

Legacy Astronomical Image

M81 group

Min S. Yun, Paul T.P. Ho, K.Y. Lo

Very Large Array (VLA)

spectral line

21 cm

1420.4 MHz

HI

RA 9:55:33.170, Dec: 69:3:55.100

2.000000 x 2.000000 degrees

Contact the archivist for a high resolution tif of this image.

Galaxies Series

Peculiar Unit