This naturally tinted composite image was produced by combining narrow band data captured through the 8.2 meter Subaru Telescope and Suprime-Cam (NAOJ) with color exposures from the .5 meter Blackbird Observatory Telescope.

The Subaru data was gathered by Aaron J.Romanowsky ( UCSC ) and Jacob A. Arnold ( UCSC ) in collaboration with Dr. David Martínez-Delgado ( MPIA ), R. Jay GaBany ( Blackbird Observatory ), the National Astronomical Observatory of Japan (NAOJ), et al. This composite image was processed and color data was supplied by R. Jay GaBany.

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Image copyright ©2009- 2011 R Jay GaBany

Ginormous Galactic Parasol Unfurls a Stream of Stars around NGC 4651

Former dwarf galaxy mergers evidenced by spectacular stellar structures

Not even a stream of stars from a long lost satellite galaxy dampens the clarity of this composite image featuring NGC 4651, the Umbrella galaxy. It was produced with the 8.2 meter Subaru telescope and the .5 meter instrument of the Blackbird Observatory.

Located towards the northern constellation of Coma Berenices, NGC 4651 drifts through the Cosmos about 35 million light years from Earth. It's noteworthy for the appearance of a crescent shaped structure extending laterally from an enormous jet that seems to emanate from the star system's heart. Combined, they conjure the appearance of an open umbrella, and its handle, shielding the galaxy from inclement cosmic weather.

The umbrella feature was previously reported by Boris Vorontsov Velyaminov in 1959 but recent research by Dr. David Martínez-Delgado ( Max Planck Institute for Astronomy ) and an international team of astronomers has concluded the crescent shaped shell at the end of the jet is the apocenter of a dwarf galaxy that was tidally disrupted then integrated into the larger spiral billions of years ago. According to the most widely accepted theory explaining the creation and evolution of galaxies, most spiral galaxies grew to their present size through the assimilation of dwarf satellite galaxies.

A possible second arc, on the opposite side of the galaxy, is partially hidden by the spiral's disk. This suggests we are observing a moderately inclined structure projected into the galaxy's halo. Computer simulations indicate dwarf satellite galaxies sometimes yo-yo back and forth, disgorging stellar material at their terminus points, when their orbits are inclined close to the parent's spiral disk. This suggests the arcs on both sides of NGC 4651 may be from a common merger.

The enormity of the unbrella structure and the reach of the jet becomes more impressive when the galaxy's 50,000 lightyear diameter is considered. For comparison, our Mikly Way galaxy is about twice the size of this distant star system.

Obtained with the National Observatory of Japan's 8.2 meter Subaru telescope, this composite image of NGC 4651 was produced by combining G, R, and OIII narrow band filtered images into a synthetic luminance channel. The luminance data was scaled then projected into a gray scale picture. The exposures ranged from less than 2 minutes to slightly over 5 minutes in duration. The final composite image was tinted with data exposed through the Blackbird Observatory .5 meter telescope. The color exposures required a total of six hours.

For more information read:
  • A Pilot Survey with Modest Aperture Telescopes
  • The survey's full PDF documentation
  • The Formation and Evolution of Galaxies
  • The Model Universe

  • Other popular images

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