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 SF State astronomer searches for signs of life on Wolf 1061 exoplanet
20.01.2017 | San Francisco State University

nachricht Molecule flash mob
19.01.2017 | Technische Universität Wien

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: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

Bodyguards in the gut have a chemical weapon

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>