Archive for the ‘In the media’ Category

Herschel Views Andromeda

January 5, 2011

We’ve been sitting on this image since just before Christmas so that it could be unveiled during the BBC Stargazing Live show last night, but I’ve been aching to get this onto the blog ever since I saw it.

This is a Herschel image of our nearest neighbour galaxy, the Andromeda galaxy, also known as M31, along with comparison images at other wavelengths.

Andromeda Galaxy

The Herschel data shows where stars are forming and where starlight is absorbed by dust. Images in the optical show us where stars are now, and the complementary X-ray data from XMM, ESA’s X-ray space telescope, show us where stars have died. The different locations picked out by these different wavelengths give hints as to how the Andromeda Galaxy has changed and evolved over its lifetime.

More information available from ESA, and from the BBC.

Apparently…

November 10, 2010

… we are Men with a Mission.

I feel compelled to point out that while I and my colleague Andrew might be men, there are plenty of women working on Herschel and Planck as well!

Dusty Galaxies & Gravitational Telescopes

November 9, 2010

It was an exciting time at the end of last week when the H-ATLAS consortium’s first paper to the journal Science came out. As a co-author I’ve been aware of this result for some time, but it was interesting to see how it got taken up by the press etc..

What we’ve found is that some bright sources seen by Herschel that appear to be associated with fairly nearby galaxies, in cosmological terms at least, are in fact dusty objects behind those nearby galaxies, having their far-IR light amplified through gravitational lensing. The process is illustrated in this figure form one of our press releases.

Herschel finds gravitationally lensed dusty galaxies

Herschel finds gravitationally lensed dusty galaxies

This result started off a long time ago, when the author of the paper, Dr Mattia Negrello, produced models in his PhD thesis of the sources we might expect to find in the Herschel surveys and came to the conclusion that many of the brightest objects would be the result of gravitational lensing. This result was included in the proposal for the H-ATLAS large area survey but I suspect that a fair number of us thought that this aspect of the proposal was a long shot – hugely important if it worked, but not that likely to be the case.

When the first H-ATLAS data came in and we started looking at the brightest reddest sources, though, it looked as if Mattia might have been onto something after all. But we couldn’t be sure. What followed was a rapid dash around many telescopes to get the multiwavelength data needed to confirm the nature of these objects. We needed optical and near-IR imaging, some of which came from Keck, we needed high resolution submm interferometry, which came form the SMA, and we needed submm spectroscopy, which came from the CSO and PdB interferometers. More data is coming from Spitzer and elsewhere, and this will appear in future papers. This is truly multiwavelength astronomy at its best, bringing a wide variety of tools and techniques together to produce the final answer.

And that answer is that Mattia was right, and there are lots of lenses to be found in the Herschel surveys. More than that, the lenses are easy to find. Previous searches for lenses in the optical and radio have had hit rates – ie. the number of lenses found to number of candidates looked at – as low as 1 in 1000. With Herschel, we seem to have a hit rate of 100%.

This has several implications. Firstly we can use the lenses as gravitational telescopes, allowing us to look at very distant objects that are much fainter than would otherwise be possible. Secondly, since mass is responsible for the lensing effect, we can use these systems to look at dark matter and how it evolves.

It’s early days yet, and the initial crop of lenses from H-ATLAS are just 5 in number, but this was based on less than 3% of the final H-ATLAS survey, and there are other Herschel surveys, like HerMES, that are adding to the database. Larger surveys with these lenses central to the science case are also planned, though we have yet to be awarded the time.

This result is also a great example of how science works. Mattia came up with this prediction as a student and has tested it in his postdoctoral work. It’s not often that the predictions and tests are done by the same person, but this is generally how things are meant to go.

The media, needless to say, has been quite interested. The story has been picked up from India to Italy. It’s also appeared on David Ike’s forums though quite where this result fits in with UFOs and alien conspiracy theories I don’t know. Perhaps most significant is that the BBC Today programme’s science correspondent was moved to write about it on his blog even though BBC journalists were on strike that day.

All in all, a great achievement for Mattia, for H-ATLAS and for Herschel!

No, we’ve not gone asleep…

October 18, 2010

… but instead, we’re swamped with a combination of SPIRE-related technical work, miscellaneous activities for our home institute (such as teaching, and the list goes on) and bottom of the pile, finding time to do some actual science. The various science teams are retrenching/reorganising to produce new papers/results now that the hectic Science Demonstration paper era has now passed – so expect to see a whole new slew of results over the next few months on here.

In the meantime, you can read the full Astronomy & Astrophysics Herschel special addition – for free!

Clustering and Sky at Night

June 15, 2010

A couple of news items I’ve missed over the last month…

Firstly a new science result, looking at the clustering of the dusty galaxies that Herschel is detecting.

Secondly, two members of the Herschel team appeared on the BBC Sky at Night programme on 7th June. You may still be able to catch this on the BBC iPlayer.

Herschel and Planck win Grand Prix!

June 14, 2010

No, not the Monaco Grand Prix, but the Grand Prix for 2010 of the AAAF, the French Association for Aeronautics and Astronautics to acknowledge their “outstanding space endeavours”.

More information about the prize can be found from ESA and from the Planck webpages.

Press release time from the ESLAB meeting

May 6, 2010

ESA held a press conference a couple of hours ago to highlight some of the results from the ESLAB meeting. If you missed the live stream earlier, you can catch it here .

A number of major programs released some mouth-watering data to the general public, ranging from high resolution studies of massive star formation in our own Galaxy (the massive bubble RCW 120, which contains an embryonic massive Wolf-Rayet star, and huge star forming complexes in Aquila and Vulpecula) to studies of the high redshift universe (the H-ATLAS program).

The H-ATLAS field
Credits: ESA/ATLAS Consortium

A picture of the first field observed in the H-ATLAS survey, made by combining the images made with the SPIRE camera at 250, 350 and 500 microns. The colours in the image are not real but have been used to represent the different infrared wavelengths. The faint blue whisps at the top of the image show dust in our own Galaxy and the bright object just above the centre of the picture is a ‘Bok globule’, a dense cloud of gas and dust, also in our Galaxy, in which a small star may be forming. The other objects in the picture are all galaxies, at distances up to 12 billion light-years. The image shows that the survey is detecting objects in our celestial ‘backyard’ and also other, further ones that we are seeing as they were not long after the Big Bang.

Vulpecula
Credits: ESA/Hi-GAL Consortium

This image, in the constellation of Vulpecula, shows an entire assembly line of newborn stars. The diffuse glow reveals the widespread cold reservoir of raw material that our Galaxy has in stock for building stars.

Large-scale turbulence from the giant colliding Galactic flows causes this material to condense into the web of filaments that we see all over the image. These are the ‘pregnant’ entities where the material becomes colder and denser. At this point, gravitational forces take over and fragment these filaments into chains of stellar embryos that can finally collapse to form baby stars.

Aquila
Credits: ESA/Hi-GAL Consortium

At the centre and the left of the image, the two massive star-forming regions G29.9 and W43 are clearly visible. These mini-starbursts are forming, as we speak, hundreds and hundreds of stars of all sizes: from those similar to our Sun, to monsters several tens of times heavier than our Sun.

These newborn large stars are catastrophically disrupting their original gas embryos by kicking away their surroundings and excavating giant cavities in the Galaxy. This is clearly visible in the ‘fluffy chimney’ below W43.

The RCW 120 bubble
Credits: ESA/PACS/SPIRE/HOBYS Consortia

RCW 120 is a galactic bubble with a large surprise. How large? At least 8 times the mass of the Sun. Nestled in the shell around this large bubble is an embryonic star that looks set to turn into one of the brightest stars in the Galaxy.

The Galactic bubble is known as RCW 120. It lies about 4300 light-years away and has been formed by a star at its centre. The star is not visible at these infrared wavelengths but pushes on the surrounding dust and gas with nothing more than the power of its starlight. In the 2.5 million years the star has existed. It has raised the density of matter in the bubble wall so much that the quantity trapped there can now collapse to form new stars.

The bright knot to the right of the base of the bubble is an unexpectedly large, embryonic star, triggered into formation by the power of the central star. Herschel’s observations have shown that it already contains between 8-10 times the mass of our Sun. The star can only get bigger because it is surrounded by a cloud containing an additional 2000 solar masses.

Not all of that will fall onto the star, even the largest stars in the Galaxy do not exceed 150 solar masses. But the question of what stops the matter falling onto the star is a puzzle for modern astronomers. According to theory, stars should stop forming at about 8 solar masses. At that mass they should become so hot that they shine powerfully at ultraviolet wavelengths.

This light should push the surrounding matter away, much as the central star did to form this bubble. But clearly sometimes this mass limit is exceeded otherwise there would be no giant stars in the Galaxy. So astronomers would like to know how some stars can seem to defy physics and grow so large. Is this newly discovered stellar embryo destined to grow into a stellar monster? At the moment, nobody knows but further analysis of this Herschel image could give us invaluable clues.

The press release (which this post is based upon quite heavily!), and high-res JPEGS of these images can be found at the ESA Herschel web site.

Additional First Science press releases – which we’ll return to later – can also be found here.

Herschel Image of the Rosette Nebula

April 14, 2010

The promised new Herschel image release has arrived – apologies for being a little late with it as I was travelling most of yesterday and running the Herschel session at NAM2010 for the rest.

The latest image is of the Rosette Nebula, a region of high mass star formation in our own galaxy, about 500 light years away. The colours indicate dust temperature, ranging from 10K (red) to 50K (blue). The bright blobs are where high mass stars, 10 times as massive as our Sun or more, are forming. You can read more about this image at the ESA Herschel pages.

Much more will be coming out of Herschel at the start of May when the first scientific results conference is held at ESTEC in the Netherlands.

New Herschel Image soon

April 12, 2010

Just heard during a talk at NAM that there should be a new Herschel image of a star forming region released by ESA later today. I don’t have the links to this yet, but you should be able to find it on the ESA Herschel website in a couple of hours. More news when I have it!

Herschel HIFI Spectrum of Orion in the News

March 13, 2010

Two page feature on the HIFI spectrum of Orion in the London Metro newspaper yesterday.