Scientists search for dark galaxies through the AGES

Apr 05, 2006

First results from the Arecibo Galaxy Environment Survey (AGES) suggest the discovery of a new dark galaxy. The AGES survey, which started in January 2006, is the most sensitive, large-scale survey of neutral hydrogen to date. Neutral hydrogen is found in most galaxies and it is a key tool in the search for dark galaxies as it can be detected even when there are no stars or other radiation sources to “shine a light” on matter.

The new candidate dark galaxy is located near NGC1156, an apparently isolated, irregularly-shaped galaxy found at the edge of the Aries constellation. The first observations in the AGES programme identified a number of new galaxies. One newly discovered source is approximately 153 million light-years from Earth and appears to be 200,000 light-years across. There is no obvious optical counterpart to the massive object.

Robbie Auld, who is presenting the results at the RAS National Astronomy Meeting in Leicester on 6th April, said, “The new source showed up clearly in the AGES survey as it contains huge amounts of hydrogen gas but it was missed in all previous searches as it doesn’t appear to contain many bright stars. The interactions between hydrogen atoms in cosmic gas clouds are enough to stimulate light emission at the neutral hydrogen “fingerprint” wavelength of 21cm. In the first stage of the AGES campaign, we have used the Arecibo radio telescope to search at this wavelength, looking for galaxies that have remained hidden from astronomers in the past. We now need to follow up observations at other wavelengths and work out exactly how many stars this new galaxy may or may not contain.”

The AGES programme, which will last for four years, is led by Cardiff University’s Dr Jonathan Davies. In addition to the Arecibo radio telescope, AGES will use a network of ground-based and space-based telescopes to observe the sky in many different wavelengths. Among those used will be the UK Infrared Telescope in Hawaii, the GALEX ultraviolet space telescope, the Hubble Space Telescope.

The techniques used in AGES have already been used on a small scale and have led to the discovery of VIRGOHI21, the first galaxy to be detected with gas, large amounts of the mysterious dark matter but no visible stars. By discovering more objects like VIRGOHI21 scientist hope to answer one of the greatest cosmological questions: if, as theoreticians predict, matter in the Universe is mainly dark then where does is all reside? The AGES team hopes that the survey will reveal exactly how much matter is hidden in dark galaxies and determine whether current theories are correct.

Source: Royal Astronomical Society

Explore further: Innovative use of pressurant extends MESSENGER's mission, enables collection of new data

add to favorites email to friend print save as pdf

Related Stories

10 facts about the Milky Way

Dec 04, 2014

The Milky Way Galaxy is an immense and very interesting place. Not only does it measure some 100,000–120,000 light-years in diameter, it is home to planet Earth, the birthplace of humanity. Our Solar System ...

It's filamentary: How galaxies evolve in the cosmic web

Nov 20, 2014

How do galaxies like our Milky Way form, and just how do they evolve? Are galaxies affected by their surrounding environment? An international team of researchers, led by astronomers at the University of ...

The mystery of pulsar rarity at the center of our galaxy

Nov 06, 2014

The galactic center is a happening place, with lots of gas, dust, stars, and surprising binary stars orbiting a supermassive black hole about three million times the size of our sun. With so many stars, as ...

Astronomy & Astrophysics: Planck 2013 results

Oct 29, 2014

Astronomy & Astrophysics is publishing a special feature of 31 articles describing the data gathered by Planck over 15 months of observations and released by ESA and the Planck Collaboration in March 2013. ...

Recommended for you

The top 101 astronomical events to watch for in 2015

Dec 24, 2014

Now in its seventh year of compilation and the second year running on Universe Today, we're proud to feature our list of astronomical happenings for the coming year. Print it, bookmark it, hang it on your ...

NASA image: Frosty slopes on Mars

Dec 24, 2014

This image of an area on the surface of Mars, approximately 1.5 by 3 kilometers in size, shows frosted gullies on a south-facing slope within a crater.

Can astronomy explain the biblical Star of Bethlehem?

Dec 24, 2014

Bright stars top Christmas trees in Christian homes around much of the world. The faithful sing about the Star of Wonder that guided the wise men to a manger in the little town of Bethlehem, where Jesus was ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.