The Whirlpool Galaxy, M51, is one of the most photographed galaxies in amateur and professional astronomy. Easily photographed and viewed by smaller telescopes, this celestial beauty is studied extensively in a range of wavelengths by large ground- and space-based observatories.
The April Hubble Heritage composite image of M51 shows visible starlight as well as light from the emission of glowing hydrogen, which is associated with the most luminous young stars in the spiral arms.
New images such as these from NASA's Hubble Space Telescope are helping researchers view in unprecedented detail the spiral arms and dust clouds of M51, the birthsite of massive and luminous stars.
M51, also known as NGC 5194, is having a close encounter with a nearby companion galaxy, NGC 5195, just off the upper edge of this image.
The companion's gravitational pull is triggering star formation in the main galaxy, as seen in brilliant detail and lit up by numerous clusters of young and energetic stars. The luminous clusters are highlighted in red by their associated emission from glowing hydrogen gas.
This Wide Field Planetary Camera 2 image enables a research group led by Nick Scoville (Caltech) to clearly define the structure of both the cold dust clouds and the hot hydrogen, and link individual clusters to their parent dust clouds.
Team members include M. Polletta (U. Geneva), S. Ewald and S. Stolovy (Caltech), R. Thompson and M. Rieke (U. of Arizona).
Intricate structure is also seen for the first time in the dust clouds.
Along the spiral arms, dust "spurs" are seen branching out almost perpendicular to the main spiral arms. The regularity and large number of these features suggests to astronomers that previous models of two-arm spiral galaxies may need to be revisited.
The new images also reveal a dust disk in the nucleus, which may provide fuel for a nuclear black hole. At near infrared wavelengths, the dusty gas clouds near the nucleus appear much brighter than in the visible images. This also provides evidence of a nuclear black hole that is surrounded by a dust-filled accretion disk.
This image was composed by the Hubble Heritage Team from Hubble archive data of M51 and is superimposed onto ground-based data taken by Travis Rector (NOAO) at the 0.9-meter telescope at the National Science Foundation's Kitt Peak National Observatory (NOAO/AURA) in Tucson, AZ.
Image Credit: NASA and The Hubble Heritage Team (STScI/AURA)
Acknowledgement: N. Scoville (Caltech) and T. Rector (NOAO)
The Space Telescope Science Institute (STScI) is operated by the Association of Universities for Research in Astronomy, Inc. (AURA), for NASA, under contract with the Goddard Space Flight Center, Greenbelt, MD. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency (ESA).
Websites with M51 images:
[Contact: Dr. Nicholas Scoville, Dr. Rodger Thompson, Dr. Howard E. Bond]