Subscribe free to our newsletters via your
. 24/7 Space News .




SKY NIGHTLY
'Eye of Sauron' provides new way of measuring distances to galaxies
by Staff Writers
Southampton, UK (SPX) Nov 28, 2014


This image shows the spiral galaxy NGC 4151. Image courtesy X-ray: NASA/CXC/CfA/J.Wang et al.; Optical: Isaac Newton Group of Telescopes, La Palma/Jacobus Kapteyn Telescope; Radio: NSF/NRAO/VLA.

A team of scientists, led by Dr Sebastian Hoenig from the University of Southampton, have developed a new way of measuring precise distances to galaxies tens of millions of light years away, using the W. M. Keck Observatory near the summit of Mauna Kea in Hawaii.

The method is similar to what land surveyors use on earth, by measuring the physical and angular, or 'apparent', size of a standard ruler in the galaxy, to calibrate the distance from this information.

The research, which is published in the journal Nature, was used to identify the accurate distance of the nearby NGC4151 galaxy, which wasn't previously available. The galaxy NGC4151, which is dubbed the 'Eye of Sauron' by astronomers for its similarity to the film depiction of the eye of the character in The Lord of the Rings, is important for accurately measuring black hole masses.

Recently reported distances range from 4 to 29 megaparsecs, but using this new method the researchers calculated the distance of 19 megaparsecs to the supermassive black hole.

Indeed, as in the famous saga, a ring plays a crucial role in this new measurement. All big galaxies in the universe host a supermassive black hole in their centre and in about a tenth of all galaxies, these supermassive black holes are growing by swallowing huge amounts of gas and dust from their surrounding environments.

In this process, the material heats up and becomes very bright -- becoming the most energetic sources of emission in the universe known as active galactic nuclei (AGN).

The hot dust forms a ring around the supermassive black hole and emits infrared radiation, which the researchers used as the ruler. However, the apparent size of this ring is so small that the observations were carried out using infrared interferometry to combine W. M. Keck Observatory's twin 10-meter telescopes, to achieve the resolution power of an 85m telescope.

To measure the physical size of the dusty ring, the researchers measured the time delay between the emission of light from very close to the black hole and the infrared emission. This delay is the distance the light has to travel (at the speed-of-light) from close to the black hole out to the hot dust.

By combining this physical size of the dust ring with the apparent size measured with the data from the Keck interferometer, the researchers were able to determine a distance to the galaxy NGC 4151.

Dr Hoenig says: "One of the key findings is that the distance determined in this new fashion is quite precise -- with only about 10 per cent uncertainty. In fact, if the current result for NGC 4151 holds for other objects, it can potentially beat any other current methods to reach the same precision to determine distances for remote galaxies directly based on simple geometrical principles. Moreover, it can be readily used on many more sources than the current most precise method."

"Such distances are key in pinning down the cosmological parameters that characterise our universe or for accurately measuring black hole masses. Indeed, NGC 4151 is a crucial anchor to calibrate various techniques to estimate black hole masses. Our new distance implies that these masses may have been systematically underestimated by 40 per cent."

Dr Hoenig, together with colleagues in Denmark and Japan, is currently setting up a new program to extend their work to many more AGN. The goal is to establish precise distances to a dozen galaxies in this new way and use them to constrain cosmological parameters to within a few per cent. In combination with other measurements, this will provide a better understanding of the history of expansion of our universe.


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only


.


Related Links
University of Southampton
Astronomy News from Skynightly.com






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle








SKY NIGHTLY
Polish astronomers spot young Stellar Bridge in the Magellanic Clouds
Washington DC (SPX) Nov 28, 2014
Polish astronomers from the Optical Gravitational Lensing Experiment (OGLE) have discovered a young stellar bridge, that forms a continuous connection between the Magellanic Clouds. This finding is based on number density maps for stellar populations found in data gathered by OGLE. This is the most extensive optical survey of this region up to date. "We find that the young population is pr ... read more


SKY NIGHTLY
Carnegie Mellon Unveils Lunar Rover "Andy"

Why we should mine the moon

Young Volcanoes on the Moon

Russia Preparing Joint Moon Exploration Agreement With EU

SKY NIGHTLY
NASA's Orion Flight Test and the Journey to Mars

Red Planet's Mystery

Orion Test Flight a Critical Step on NASA's Journey to Mars

Traces of possible Martian biological activity inside a meteorite

SKY NIGHTLY
ISS astronauts will have to wait until April for espresso

NASA video shows off Orion cockpit

New Display Counts Down for New Generation

NASA's Orion capsule poised for first test launch

SKY NIGHTLY
Service module of China's returned lunar orbiter reaches L2 point

China Launches Second Disaster Relief Satellite

China expects to introduce space law around 2020

China launches new remote sensing satellite

SKY NIGHTLY
NASA's CATS Eyes Clouds, Smoke and Dust from the Space Station

ISS Enables Interplanetary Space Exploration

3-D Printer Creates First Object in Space on ISS

Soyuz docks at Space Station; Expedition 42 joins crew

SKY NIGHTLY
Japan launches rocket carrying asteroid probe

Go-ahead given for Ariane 5 dual-payload mission

Launch of European Ariane-5 Space Rocket From Kourou Postponed

After wrangle, Europe set to approve Ariane 6 launcher

SKY NIGHTLY
'Mirage Earth' exoplanets may have burned away chances for life

Stardust Not Likely to Block Planet Portraits

Ground-based detection of exoplanets

Finding infant earths and potential life just got easier

SKY NIGHTLY
Space travel is a bit safer than expected

Street cleaners in New York have help from insect garbage-munchers

Laser link offers high-speed delivery

Researchers develop building material that cools by reflecting heat into space




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.