Galaxy Merger "The true nature of Arp 220, a peculiar 14th-magnitude galaxy in Serpens Caput, may finally be coming to light.
The gravitational turmoil of this galactic merger seems responsible for the vigorous starforming activity being observed there, and it might in some way explain a surprise finding in 2011, namely, that Arp 220 spawns a supernova every few months.
The astronomers used a worldwide network of radio telescopes in five countries, including Sweden, to be able to create extremely sharp images of the galaxy Arp 220. The scientists observed around 40 radio sources in the center of the galaxy Arp 220.
The number is nevertheless consistent with how fast stars are forming in Arp 220.
The international team took extremely deep exposures of archetypal colliding galaxies, including "the Antennae" galaxies in constellation Corvus, "Arp 220
" in constellation Serpens and "Mrk 231" in constellation Big Dipper, and 10 additional objects.
Individual cases of strong X-ray clusters are exemplified by elongations and connections as shown in the ejecting galaxy Arp 220
, in Abell 3667 and from NGC 720 (again, summarized in Arp, 2003 ).
In another starburst, Arp 220
, two colliding galaxies have coalesced, too.
"It's an active galaxy with a hidden quasar at its core!" "No, it's the site of a furious burst of star formation!" So might scientists spar, were the decade-long debate on the nature of Arp 220 to take place on a television talk show.
In any case, most researchers agree on one point: Arp 220 was created by the violent merger of two gas-rich galaxies, a process amply illustrated in an earlier phase by the Antennae galaxies in Corvus (S&T: March 1998, page 48).
When the Hubble Space Telescope peered into the center of an oddly shaped galaxy called Arp 220
, it imaged six densely packed clusters of stars -- the largest star-packed regions ever observed by a telescope.
A LOOK through the pages of this magazine reveals a great variety of seemingly incomprehensible names for celestial objects: Arp 220
, MWC 560, Q 0957 + 561, 1E 1740.7-2942, 3C 273, PSR 1257 + 12.
In visible light, the galaxy Arp 220
looks unimpressive, but at infrared wavelengths it shines brighter than 100 Milky Ways.