Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


The Antennae Galaxies move closer

The Antennae Galaxies are among the closest known merging galaxies. The two galaxies, also known as NGC 4038 and NGC 4039, began interacting a few hundred million years ago, creating one of the most impressive sights in the night sky. They are considered by scientists as the archetypal merging galaxy system and are used as a standard against which to validate theories about galaxy evolution.

An international group of scientists led by Ivo Saviane from the European Southern Observatory has used Hubble’s Advanced Camera for Surveys and Wide Field Planetary Camera 2 to observe individual stars spawned by the colossal cosmic collision in the Antennae Galaxies.

They reached an interesting and surprising conclusion. By measuring the colours and brightnesses of red giant stars in the system, the scientists found that the Antennae Galaxies are much closer than previously thought: 45 million light-years instead of the previous best estimate of 65 million light-years.

The team targeted a region in the relatively quiescent outer regions in the southern tidal tail, away from the active central regions. This tail consists of material thrown from the main galaxies as they collided. The scientists needed to observe regions with older red giant stars to derive an accurate distance. Red giants are known to reach a standard brightness, which can then be used to infer their distance. The method is known as the tip of the red giant branch (TRGB).

The proximity of the Antennae system means it is the best-studied galaxy merger in the sky, with a wealth of observational data to be compared to the predictions of theoretical models. Saviane says: “All aspiring models for galaxy evolution must be able to account for the observed features of the Antennae Galaxies, just as respectable stellar models must be able to match the observed properties of the Sun. Accurate models require the correct merger parameters, and of these, the distance is the most essential”.

The previous canonical distance to the Antennae Galaxy was about 65 million light-years although values as high as 100 million light years have been used. Our Sun is only eight light-minutes away from us, so the Antennae Galaxies may seem rather distant, but if we consider that we already know of galaxies that are more than ten billion light-years away, the two Antennae Galaxies are really our neighbours.

The previous larger distance required astronomers to invoke some quite exceptional physical characteristics to account for the spectacular system: very high star-formation rates, supermassive star clusters, ultraluminous X-ray sources etc. The new smaller distance makes the Antennae Galaxies less extreme in terms of the physics needed to explain the observed phenomena. For instance, with the smaller distance its infrared radiation is now that expected of a “standard” early merging event rather than that of an ultraluminous infrared galaxy. The size of the star clusters formed as a consequence of the Antennae merger now agree with those of clusters created in other mergers instead of being 1.5 times as large.

The Antennae Galaxies are named for the two long tails of stars, gas and dust that resemble the antennae of an insect. These “antennae” are a physical result of the collision between the two galaxies. Studying their properties gives us a preview of what may happen when our Milky Way galaxy collides with the neighbouring Andromeda galaxy in several billion years. Although galaxy mergers today are not common, it is believed that in the past they were an important channel of galaxy evolution. Therefore understanding the physics of galaxy mergers is a very important task for astrophysicists.

The Antennae are located in the constellation of Corvus, the Crow.

Lars Christensen | alfa
Further information:

More articles from Physics and Astronomy:

nachricht Double layer of graphene helps to control spin currents
18.10.2019 | University of Groningen

nachricht Analysis of Galileo's Jupiter entry probe reveals gaps in heat shield modeling
17.10.2019 | American Institute of Physics

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: Solving the mystery of quantum light in thin layers

A very special kind of light is emitted by tungsten diselenide layers. The reason for this has been unclear. Now an explanation has been found at TU Wien (Vienna)

It is an exotic phenomenon that nobody was able to explain for years: when energy is supplied to a thin layer of the material tungsten diselenide, it begins to...

Im Focus: An ultrafast glimpse of the photochemistry of the atmosphere

Researchers at Ludwig-Maximilians-Universitaet (LMU) in Munich have explored the initial consequences of the interaction of light with molecules on the surface of nanoscopic aerosols.

The nanocosmos is constantly in motion. All natural processes are ultimately determined by the interplay between radiation and matter. Light strikes particles...

Im Focus: Shaping nanoparticles for improved quantum information technology

Particles that are mere nanometers in size are at the forefront of scientific research today. They come in many different shapes: rods, spheres, cubes, vesicles, S-shaped worms and even donut-like rings. What makes them worthy of scientific study is that, being so tiny, they exhibit quantum mechanical properties not possible with larger objects.

Researchers at the Center for Nanoscale Materials (CNM), a U.S. Department of Energy (DOE) Office of Science User Facility located at DOE's Argonne National...

Im Focus: Novel Material for Shipbuilding

A new research project at the TH Mittelhessen focusses on the development of a novel light weight design concept for leisure boats and yachts. Professor Stephan Marzi from the THM Institute of Mechanics and Materials collaborates with Krake Catamarane, which is a shipyard located in Apolda, Thuringia.

The project is set up in an international cooperation with Professor Anders Biel from Karlstad University in Sweden and the Swedish company Lamera from...

Im Focus: Controlling superconducting regions within an exotic metal

Superconductivity has fascinated scientists for many years since it offers the potential to revolutionize current technologies. Materials only become superconductors - meaning that electrons can travel in them with no resistance - at very low temperatures. These days, this unique zero resistance superconductivity is commonly found in a number of technologies, such as magnetic resonance imaging (MRI).

Future technologies, however, will harness the total synchrony of electronic behavior in superconductors - a property called the phase. There is currently a...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

International Symposium on Functional Materials for Electrolysis, Fuel Cells and Metal-Air Batteries

02.10.2019 | Event News

NEXUS 2020: Relationships Between Architecture and Mathematics

02.10.2019 | Event News

Optical Technologies: International Symposium „Future Optics“ in Hannover

19.09.2019 | Event News

Latest News

Energy Flow in the Nano Range

18.10.2019 | Power and Electrical Engineering

MR-compatible Ultrasound System for the Therapeutic Application of Ultrasound

18.10.2019 | Medical Engineering

Double layer of graphene helps to control spin currents

18.10.2019 | Physics and Astronomy

Science & Research
Overview of more VideoLinks >>>