Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Moving Closer to the Grand Spiral

02.08.2005


VLT Enables Most Accurate Distance Measurement to Spiral Galaxy NGC 300



An international team of astronomers from Chile, Europe and North America [1] is announcing the most accurate distance yet measured to a galaxy beyond our Milky Way’s close neighbours. The distance was determined using the brightness variation of a type of stars known as "Cepheid variables".

The team used the ISAAC near-infrared camera and spectrometer on ESO’s 8.2-m VLT Antu telescope to obtain deep images in the near-infrared of three fields in the spiral galaxy NGC 300. Together these fields contain 16 long-period Cepheids. These stars had previously been discovered by the team in a wide-field imaging survey of this galaxy conducted with the Wide Field Imager (WFI) camera on the ESO/MPG 2.2-m telescope at La Silla.


The spiral galaxy NGC 300 is a beautiful representative of its class, a Milky-Way-like member of the prominent Sculptor group of galaxies in the southern constellation of the same name.

The astronomers derive a distance to NGC 300 of a little above 6 million light-years [2]. "The VLT data have led to accurate period-luminosity relations in the J- and K- bands, allowing us to determine the distance to NGC 300 with an unprecedented uncertainty of only three percent", says Wolfgang Gieren, of the University of Concepcion (Chile) and leader of the team. One of the reasons for this high accuracy was the opportunity to precisely combine the new near-infrared ISAAC data with the previous optical WFI data.

Cepheid variables constitute a key element in the measurement of distances in the Universe. It has been known for many years that the pulsation period of a Cepheid-type star depends on its intrinsic brightness (its "luminosity"). Thus, once its period has been measured, the astronomers can calculate its luminosity. By comparing this to the star’s apparent brightness in the sky, they can obtain the distance to the star. This fundamental method has allowed some of the most reliable measurements of distances in the Universe and has been essential for all kinds of astrophysics, from the closest stars to the remotest galaxies.

This first Cepheid distance based on near-infrared imaging with the Very Large Telescope is a milestone in the team’s Araucaria Project in which they seek to improve the local calibration of the distance scale with stellar standard candles, including Cepheid variables, by determining precisely how these standard candles depend on a galaxy’s properties, such as its content in chemical elements and age.

Henri Boffin | alfa
Further information:
http://www.eso.org/outreach/press-rel/pr-2005/pr-20-05.html

More articles from Physics and Astronomy:

nachricht UNLV study unlocks clues to how planets form
13.12.2018 | University of Nevada, Las Vegas

nachricht Unprecedented Views of the Birth of Planets
13.12.2018 | Universität Heidelberg

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: An energy-efficient way to stay warm: Sew high-tech heating patches to your clothes

Personal patches could reduce energy waste in buildings, Rutgers-led study says

What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...

Im Focus: Lethal combination: Drug cocktail turns off the juice to cancer cells

A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.

The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...

Im Focus: New Foldable Drone Flies through Narrow Holes in Rescue Missions

A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.

Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...

Im Focus: Topological material switched off and on for the first time

Key advance for future topological transistors

Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...

Im Focus: Researchers develop method to transfer entire 2D circuits to any smooth surface

What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.

Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

 
Latest News

Magic number colloidal clusters

13.12.2018 | Life Sciences

UNLV study unlocks clues to how planets form

13.12.2018 | Physics and Astronomy

Live from the ocean research vessel Atlantis

13.12.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>