Atomic Hydrogen in M81

https://www.nrao.edu/archives/plugins/Dropbox/files/M81_hi.jpg

Description

The galaxy M81 is a spiral galaxy about 11 million light-years from Earth. It is about 50,000 light-years across. In the optical (not shown), the galaxy is known as a "Grand Design" spiral, for its pair of symmetric, well-defined spiral arms. This image, which only shows the cold atomic hydrogen gas in the galaxy, clearly shows that the gas also follows this grand design pattern. In this pseudocolor image, red indicates higher gas densities and blue weaker emission.
The observations consist of data taken with the VLA in the B-array, C-array and D-array configurations for a total of more than 60 hours of observing time. Two pointings and two velocity settings were used. The resolution is 12". The continuum sources have not been removed from the map.

Creator

Legacy Astronomical Images

Rights

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

Type

Legacy Astronomical Image

Object Name

M81

Investigators

D. S. Adler, D. J. Westpfahl

Telescope

Very Large Array (VLA)

Observation Date

1992-08-01

Type of Observation

spectral line

Wavelength

21 cm

Frequency

1420.4 MHz

Species

HI

Center of Image

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

Field of View

0.650000 x 0.650000 degrees

Link to journal article

Notes

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

Series

Galaxies Series

Unit

Spiral Unit

Citation

Legacy Astronomical Images, “Atomic Hydrogen in M81,” NRAO Archives, accessed December 3, 2021, https://www.nrao.edu/archives/items/show/33574.