The stars at the centre of the Milky Way, in infrared. Credit: ESO/S. Gillessen et al.
My colleagues at ESO have just published a press release I worked on about a study into the black hole at the centre of our galaxy — the Milky Way. The release is the largest one I’ve done to date, and great fun to do too — not least because of the several fascinating intertwined stories within it. I’ll start with the big one though.
That is, a 16 year long study by astronomers (from the Max-Planck-Institute for Extraterrestrial Physics in Germany) has given us the best empirical evidence, so far, of the existence of truly massive black holes. Not only does the evidence verify the existence of these leviathan objects, it also shows that one is “beyond any reasonable doubt” hiding at the heart of the Milky Way, with a mass of some four million times that of the Sun. Here’s a section from the start of the release:
“By watching the motions of 28 stars orbiting the Milky Way’s most central region with admirable patience and amazing precision, astronomers have been able to study the super-massive black hole lurking there. The new research marks the first time that the orbits of so many of these central stars have been calculated precisely and reveals information about the enigmatic formation of these stars — and about the black hole to which they are bound.”
An artist’s impression of the orbits of the central stars. Credit: ESO
Incredibly, over the course of the study, one star (known as ‘S2’) was even able to make a complete orbit of the Milky Way’s hub. Yet it gets even better. Thanks to the observations we can now watch S2 whirl around (with all its companions) in actual infrared images from ESO’s telescopes, taken over the 16 years. The telescopes use adaptive optics to counteract the problems associated with trying to observe through Earth’s turbulent atmosphere. Observing in the infrared also allows the telescopes to penetrate the thick dust and gas of the Galaxy, and thus peer straight at these intriguing central stars. You can watch the animation of these real images in a (7MB) Quicktime video here. The motion of the stars has been sped up by just over 30 million times!
A frame from the video (see link above). Credit: ESO/ R.Genzel and S. Gillessen
If you want to get the full story you can read the whole press release here. There are some great videos to go with the article so be sure to have a look at them on the ESO webpage. And of course check out the second episode of the ESOcast (summarising the result), here. It’s great to see that, already, this fascinating result has sparked the interest of some major news outlets including here, here and here.
Omega Centauri as seen by the WFI. Credit: ESO/EIS
I’ve just had a new press release published over at the European Southern Observatory’s website. It’s about an image (above) of the stunning globular cluster Omega Centauri, taken with the observatory’s Wide Field Imager camera. Here’s a snippet from the release:
This new image is based on data collected with the Wide Field Imager (WFI), mounted on the 2.2-metre diameter Max-Planck/ESO telescope, located at ESO’s La Silla observatory, high up in the arid mountains of the southern Atacama Desert in Chile. Omega Centauri is about 150 light-years across and is the most massive of all the Milky Way’s globular clusters. It is thought to contain some ten million stars!
Omega Centauri is roughly 12 billion years old and had long been thought to be just a massive globular cluster – a huge, roughly spherical, collection of ancient stars. But recent research has found that there are several generations of stars in Omega Centauri – not a typical trait of globular clusters. This discovery has led to some astronomers suggesting that the cluster is actually the remnant centre of a dwarf galaxy. You can read the full story here. And be sure to have a look at the high resolution image, to get a real sense of perspective, with the millions of stars in the cluster. I’ve included a small crop below.
A crop of the left hand side of the new WFI image. Credit: ESO/EIS
Last week ESO, the European Southern Observatory, released a press release about their observations of the gamma-ray burst GRB 080319B – one the brightest gamma-ray bursts ever seen – that occurred in March of this year. The press release covers the results of a new investigation into the burst. Astronomers who studied the burst have come to a startling conclusion about its orientation! From the press release:
“We conclude that the burst’s extraordinary brightness arose from a jet that shot material almost directly towards Earth at almost the speed of light,” says Guido Chincarini, a member of the team.
Above: Artist’s impression of GRB 080319B. Credit ESO
I was asked by the press team at the ESO headquarters, in Germany, to write the background story of that burst, including the many different observations made by telescopes around the world and how and when it appeared. The finished article has now been posted alongside the release as a two page pdf. You can read the ESO press release here and also download my feature story on GRB 080319B here (pdf download in link).
The stunning galaxy M83. Credit: ESO
My first press release for the European Southern Observatory has now been released. It accompanies what is, of course, the real interest in the story – a fantastic new image from the observatory’s Wild Field Imager camera. It shows the stunning spiral galaxy M83, arguably one of the most beautiful galaxies in Messier’s famous catalogue of deep sky objects. Here’s a snippet from the press release:
This dramatic image of the galaxy Messier 83 was captured by the Wide Field Imager at ESO’s La Silla Observatory, located high in the dry desert mountains of the Chilean Atacama Desert. Messier 83 lies roughly 15 million light-years away towards the huge southern constellation of Hydra (the sea serpent). It stretches over 40 000 light-years, making it roughly 2.5 times smaller than our own Milky Way. However, in some respects, Messier 83 is quite similar to our own galaxy. Both the Milky Way and Messier 83 possess a bar across their galactic nucleus, the dense spherical conglomeration of stars seen at the centre of the galaxies.
You can read the full press release and download a hugggeeee version of the image here.
The European Southern Observatory is running an international competition for students (in primary or secondary education) called ‘Catch a Star’. Entrants can either submit reports or artwork on an astronomical topic of their choice.
The deadline is Friday 29th February 2008. Prizes include T-shirts, DVDs, posters as well as (for the top prizes) trips to various worldwide observatories including ESO’s Paranal site in Chile!
For more information and the full rules, details and requirements visit the ESO ‘Catch A Star’ site here.