Celestial Atlas
PGC 56500 - 56999 ←     PGC Objects: PGC 57000 - 57499 Link for sharing this page on Facebook     → PGC 57500 - 57999
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PGC 57129 (= Arp 188) -- The "Tadpole" Galaxy
A 14th-magnitude spiral galaxy (type SB(s)c pec) in
Draco (RA 16 06 04, Dec +55 25 32)

PGC 57129, also known as Arp 188, or the "Tadpole", is the result of a galactic collision. The top image (below) shows a giant spiral galaxy, and partially hidden behind it at upper left, a smaller galaxy, which is undergoing a close encounter with the giant. As a result of the encounter huge clouds of gas, dust and stars have been scattered all around the spiral, and stretch vast distances into intergalactic space, as shown in the middle image, which shows both the spiral and its "tail". Bright blue clusters of hot young stars, each of which contains as many as a million stars and tens of millions of solar masses, are seen scattered around the galaxy, and along the tail. These clusters were formed as the gas and dust torn from the galaxy was compressed to form new stars. Over a period of time, the clusters which are nearer the main galaxy will probably evolve into globular clusters scattered around its halo. The bright clusters near the end of the tail will probably become dwarf galaxies, new satellites of the original galaxy. Meanwhile, the galaxy which caused this chaos will pass on, into intergalactic space, never to return to the site of the encounter. Based on its recessional velocity of 9400 km/sec, the galaxy is about 420 million light years away. Given that and its apparent size of 1.7 by 0.75 arcmin, it is about 220 thousand light years across, but the two arcmin long "tail" adds another 280 thousand light years to its length. Note: The upper images shown here were taken with the Hubble Space Telescope Advanced Camera for Surveys in April 2002. The wide-field ACS image shows over 6000 galaxies, at distances of up to 13 billion light years. This represents twice as many galaxies as seen in the "deepest" images taken with the former Wide Field and Planetary Camera, despite taking only a twelfth as long to create the image. As a result, its release was intended not only to show off the spectacular interaction seen here, but also to highlight the extraordinary capabilities of the new camera.

Above, a Hubble Space Telescope closeup of the main galaxy (cropped version of image below)
Below, a view of the entire galaxy, including its tail (Image Credits: H. Ford (JHU), G. Illingworth (UCSC/LO), M.Clampin (STScI), G. Hartig (STScI), the ACS Science Team, ESA, NASA)

Below, a 12 arcmin wide region centered on the galaxy, with North at the top
Wikisky SDSS image of region near Arp 188
Celestial Atlas
PGC 56500 - 56999 ←     PGC Objects: PGC 57000 - 57499     → PGC 57500 - 57999