Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Astronomers find Paschen in the bar

26.06.2003


An international team of astronomers have used a unique instrument on the 8-m Gemini South Telescope to determine the ages of stars across the central region of the barred spiral galaxy, M83. Preliminary results provide the first hints of a domino model of star formation where star formation occurs in a time sequence, driven by the movements of gas and stars in the central bar.



The new instrument, called CIRPASS, simultaneously produces 500 spectra, taken from across the whole region of interest, which act as a series of "fingerprints". Encoded in these "fingerprints" is not only all the information the team required to determine when individual groups of stars formed, but also information on their movements and chemical properties. Dr. Johan Knapen, project co-investigator said, "The unique combination of a state-of-the-art instrument like CIRPASS with one of the most powerful telescopes available is now providing us with truly sensational observations."

M83 is a "grand-design" spiral galaxy undergoing an intense burst of star formation in its central bar region. Large-scale images of the visible light from the galaxy, taken with ground based telescopes, show a pronounced bar across the middle of the galaxy, seen as a diagonal white structure. Astronomers believe that it is the influence of this bar that leads a concentration of gas in the central regions of the galaxy from which stars are born. "The central region of M83 is enshrouded in dust but, by using CIRPASS, which operates in the infra-red not the visible, we are able to see through this dust and investigate the hidden physical processes at work in the galaxy," said Dr Ian Parry, leader of the CIRPASS instrumentation team.


Two competing theories strive to explain the burst of star formation in the centre of the galaxy, M83. One theory suggests that stars form randomly across the whole nuclear region. A second model, favoured by the observational team, proposes that star-formation is triggered by the bar structure. In this model, the rotation of gas and stars in the bar causes stars to be formed sequentially, in a domino manner.

Using a technique first demonstrated by Dr. Stuart Ryder and colleagues, the team searched for a hydrogen emission feature, the Paschen-beta line, within the galaxy’’s "fingerprints". The measurement of this feature indicates the presence of hot young stars. By comparing the strengths of the Paschen-beta emission with the amount of absorption from carbon-monoxide (arising in the cool atmospheres of old giant stars) the team are able determine the age of the stars in each region of the galaxy. "A detailed analysis of the data is underway but initial results hint at a complex sequence of star formation," said Dr Robert Sharp, instrument support scientist with CIRPASS.

Preliminary analysis of other emission features (due to Paschen-beta and ionized iron) revealed a potentially intriguing result. "Ionized iron enables us to trace past supernova explosions. The observations indicate that energy from exploding stars (supernovae) may be being passed into regions of undisturbed gas causing further massive star formation," said Dr. Stuart Ryder, principle investigator.

While some members of the instrument team are presenting their work at an exhibition at the Royal Society in London on 1st, 2nd and 3rd July, CIRPASS is back on the Gemini South Telescope in Chile, performing the next set of observations.

Lisa Wright | alfa
Further information:
http://www.ast.cam.ac.uk/~ljw/Press/cirpass_final.html

More articles from Physics and Astronomy:

nachricht The taming of the light screw
22.03.2019 | Max-Planck-Institut für Struktur und Dynamik der Materie

nachricht Magnetic micro-boats
21.03.2019 | Max-Planck-Institut für Polymerforschung

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: The taming of the light screw

DESY and MPSD scientists create high-order harmonics from solids with controlled polarization states, taking advantage of both crystal symmetry and attosecond electronic dynamics. The newly demonstrated technique might find intriguing applications in petahertz electronics and for spectroscopic studies of novel quantum materials.

The nonlinear process of high-order harmonic generation (HHG) in gases is one of the cornerstones of attosecond science (an attosecond is a billionth of a...

Im Focus: Magnetic micro-boats

Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains.

The magnetic properties of a material control how this material responds to the presence of a magnetic field. Iron oxide is the main component of rust but also...

Im Focus: Self-healing coating made of corn starch makes small scratches disappear through heat

Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.

Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...

Im Focus: Stellar cartography

The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.

A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...

Im Focus: Heading towards a tsunami of light

Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.

"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Solving the efficiency of Gram-negative bacteria

22.03.2019 | Life Sciences

Bacteria bide their time when antibiotics attack

22.03.2019 | Life Sciences

Open source software helps researchers extract key insights from huge sensor datasets

22.03.2019 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>