Anatomy of a cosmic bird
December 21, 2007
A 30-min VLT/NACO K-band exposure has been combined with archive HST/ACS B and I-band images to produce a three-color image of the "Bird" interacting galaxy system. The NACO image has allowed astronomers to not only see the two previously known galaxies, but to identify a third, clearly separate component, an irregular, yet fairly massive galaxy that seems to form stars at a frantic rate. The final color image was produced by Henri Boffin (ESO). Credit: ESO
Using ESO's Very Large Telescope, an international team of astronomers has discovered a stunning rare case of a triple merger of galaxies. This system, which astronomers have dubbed 'The Bird' - albeit it also bears resemblance with a cosmic Tinker Bell - is composed of two massive spiral galaxies and a third irregular galaxy.
The galaxy ESO 593-IG 008, or IRAS 19115-2124, was previously merely known as an interacting pair of galaxies at a distance of 650 million light-years. But surprises were revealed by observations made with the NACO instrument attached to ESO's VLT, which peered through the all-pervasive dust clouds, using adaptive optics to resolve the finest details.
Underneath the chaotic appearance of the optical Hubble images - retrieved from the Hubble Space Telescope archive - the NACO images show two unmistakable galaxies, one a barred spiral while the other is more irregular.
The surprise lay in the clear identification of a third, clearly separate component, an irregular, yet fairly massive galaxy that seems to be forming stars at a frantic rate.
"Examples of mergers of three galaxies of roughly similar sizes are rare," says Petri Väisänen, lead author of the paper reporting the results. "Only the near-infrared VLT observations made it possible to identify the triple merger nature of the system in this case."
Because of the resemblance of the system to a bird, the object was dubbed as such, with the 'head' being the third component, and the 'heart' and 'body' making the two major galaxy nuclei in-between of tidal tails, the 'wings'. The latter extend more than 100,000 light-years, or the size of our own Milky Way.
Subsequent optical spectroscopy with the new Southern African Large Telescope, and archive mid-infrared data from the NASA Spitzer space observatory, confirmed the separate nature of the 'head', but also added further surprises. The 'head' and major parts of the 'Bird' are moving apart at more than 400 km/s (1.4 million km/h!). Observing such high velocities is very rare in merging galaxies. Also, the 'head' appears to be the major source of infrared luminosity in the system, though it is the smallest of the three galaxies.
"It seems that NACO has caught the action right at the time of the first high-speed fly-by of the 'head' galaxy through the system consisting of the other two galaxies," says Seppo Mattila, member of the discovery team. "These two galaxies must have met earlier, probably a couple of hundred million years ago."
The 'head' is forming stars violently, at a rate of nearly 200 solar masses per year, while the other two galaxies appear to be at a more quiescent epoch of their interaction-induced star formation history.
The 'Bird' belongs to the prestigious family of luminous infrared galaxies, with an infrared luminosity nearly one thousand billion times that of the Sun. This family of galaxies has long been thought to signpost important events in galaxy evolution, such as mergers of galaxies, which in turn trigger bursts of star formation, and may eventually lead to the formation of a single elliptical galaxy.
Source: ESO
-
New map of the universe reveals its history for the past six-billion years
Jan 13, 2012 |
4.6 / 5 (9) |
19
-
Nobel winner thought prize call was 'student joke'
Oct 05, 2011 |
5 / 5 (1) |
7
-
The observatory above the clouds
Sep 20, 2011 |
5 / 5 (6) |
5
-
An atlas of the Milky Way
Aug 30, 2011 |
4.6 / 5 (9) |
1
-
Researchers detail how a distant black hole devoured a star
Aug 24, 2011 |
4.6 / 5 (11) |
24
-
Engineers build first sub-10-nm carbon nanotube transistor
Feb 01, 2012 |
4.9 / 5 (31) |
30
-
Something old, something new: Evolution and the structural divergence of duplicate genes
Jan 31, 2012 |
4.6 / 5 (7) |
1
-
The hidden nanoworld of ice crystals: Revealing the dynamic behavior of quasi-liquid layers
Jan 30, 2012 |
5 / 5 (3) |
1
-
Stock market network reveals investor clustering
Jan 27, 2012 |
3.9 / 5 (23) |
8
-
Of microchemistry and molecules: Electronic microfluidic device synthesizes biocompatible probes
Jan 26, 2012 |
5 / 5 (1) |
0
-
Titan's lack of impact craters
Feb 09, 2012
-
Real pictures of black hole eating a star?
Feb 08, 2012
-
Hypothetical way to travel faster than light, but not technically exceed lightspeed
Feb 06, 2012
-
How do scientists monitor the Sun's activity?
Feb 05, 2012
-
Search patterns in observational studies
Feb 05, 2012
-
Derivation of Pogson's law
Feb 03, 2012
- More from Physics Forums - General Astronomy
More news stories
NASA sees wide-eyed cyclone Jasmine
Cyclone Jasmine's eye has opened wider on NASA satellite imagery, as it moves through the Southern Pacific Ocean.
Space & Earth / Earth Sciences
20 minutes ago |
not rated yet |
0
NASA sees Giovanna reach cyclone strength, threaten Madagascar
Tropical Storm 12S built up steam and became a cyclone on February 10, 2012 as NASA's Terra satellite passed overhead. Residents of east-central Madagascar should prepare for this cyclone to make landfall ...
Space & Earth / Earth Sciences
19 minutes ago |
not rated yet |
0
Humans may have helped the decline of African rainforests 3000 years ago
(PhysOrg.com) -- Large areas of rainforests in Central Africa mysteriously disappeared over three thousand years ago, to be replaced by savannas. The prevailing theory has been that the cause was a change ...
Could Venus be shifting gear?
(PhysOrg.com) -- ESAs Venus Express spacecraft has discovered that our cloud-covered neighbour spins a little slower than previously measured. Peering through the dense atmosphere in the infrared, the ...
Space & Earth / Space Exploration
8 hours ago |
5 / 5 (5) |
7
|
Mars Science Laboratory computer issue resolved
(PhysOrg.com) -- Engineers have found the root cause of a computer reset that occurred two months ago on NASA's Mars Science Laboratory and have determined how to correct it.
Space & Earth / Space Exploration
9 hours ago |
5 / 5 (5) |
3
|
CIA website offline, Anonymous takes credit
The website of the Central Intelligence Agency was unresponsive on Friday after the hacker group Anonymous claimed to have knocked it offline.
Complex wiring of the nervous system may rely on a just a handful of genes and proteins
Researchers at the Salk Institute have discovered a startling feature of early brain development that helps to explain how complex neuron wiring patterns are programmed using just a handful of critical genes. ...
The power of estrogen -- male snakes attract other males
A new study has shown that boosting the estrogen levels of male garter snakes causes them to secrete the same pheromones that females use to attract suitors, and turned the males into just about the sexiest ...
New error-correcting codes guarantee the fastest possible rate of data transmission
Error-correcting codes are one of the triumphs of the digital age. Theyre a way of encoding information so that it can be transmitted across a communication channel such as an optical fiber o ...
Small modular reactor design could be a 'SUPERSTAR'
(PhysOrg.com) -- Though most of today's nuclear reactors are cooled by water, we've long known that there are alternatives; in fact, the world's first nuclear-powered electricity in 1951 came from a reactor ...
Curry spice component may help slow prostate tumor growth
Curcumin, an active component of the Indian curry spice turmeric, may help slow down tumor growth in castration-resistant prostate cancer patients on androgen deprivation therapy (ADT), a study from researchers ...