Radio/Optical Composite of M51

https://www.nrao.edu/archives/plugins/Dropbox/files/WhirlpoolGalaxy-M51_VR11I_hi.jpg

Description

Three separate sets of observations are involved in this composite image of the spiral galaxy M51, also known as the "Whirlpool Galaxy". The optical image (depicted by green and yellow colors in the above image) highlights the younger stars, as well as the dust; the latter can be seen as dust lanes in the spiral arms of M51 itself and in obscuring the eastern (left hand) part of its companion, NGC5195. The continuum radio emission (depicted by red in the image) is partly due to thermal emission from HII regions, partly to synchrotron emission from relativistic electrons moving in magnetic fields, delineating areas of high compression (i.e. the dust lanes). The spectral-line observations of neutral atomic hydrogen (depicted by blue) gives us the distribution, as well as the kinematics, of the neutral hydrogen gas.
Optical image is a photographic plate taken in Blue light with the KPNO 4m telescope. The radio continuum image is a 1.4 GHz image from the VLA with 7 arcsec resolution. The 21cm line observations are from combined VLA B-array and D-array observations, shown at a resolution of 8 arcsec.

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

M51

Investigators

A.H. Rots, J.M. van der Hulst, P.E. Seiden, R.C. Kennicutt, P.C. Crane, A. Bosma, L. Athanassoula, D.M. Elmegreen

Telescope

Very Large Array (VLA)

Observation Date

1983-12-31

Type of Observation

spectral line

Wavelength

21 cm

Frequency

1420.4 MHz

Species

HI

Center of Image

RA 13:27:46.500, Dec: 47:27:9.000

Field of View

0.283300 x 0.283300 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, “Radio/Optical Composite of M51,” NRAO Archives, accessed December 3, 2021, https://www.nrao.edu/archives/items/show/33576.