Archive for SPIRE

The Travellers and the Rest

Posted in Biographical with tags , , , , , , , , , , on January 15, 2011 by telescoper

Yesterday’s journey to the Big Smoke wasn’t as bad as it might have been, although it was a bit frustrating at times. The train was diverted through Bath to avoid flooding near Bristol, which added about 20 minutes to the journey time. That was expected, so didn’t cause any major anxiety. After the rather scenic detour we found ourselves back in familiar territory on the Cardiff-London line, Swindon. I never thought I’d see the day when I was pleased to arrive at Swindon! However, my pleasure soon evaporated when we sat on the platform at Swindon without moving, and with no announcements or information or explanation, for another 15 minutes. Obviously 25 minutes late just wasn’t late enough for First Great Western, so they had to hold the train to enhance further their record of unpunctuality. In the end we arrived at Paddington 40 minutes late. Not good.

I still got to the meeting in time for a quick cup of tea before the afternoon’s proceedings. Straight away there was some great news. The President of the RAS, Prof. Roger Davies, announced the recipients of this year’s medals and awards and among them was Cardiff’s own Matt Griffin, who receives the Jackson-Gwilt Medal.  According to the RAS website

The Jackson-Gwilt Medal is available for award annually for the invention, improvement or development of astronomical instrumentation or techniques; for achievement in observational astronomy; or for achievement in research in the history of astronomy.

Matt Griffin’s citation reads as follows:

This year’s winner is Professor Matt Griffin of the University of Cardiff, for his work on instrumentation for astronomy in the submillimetre waveband, the region of the electromagnetic spectrum between the far-infrared and microwave wavebands.

Matt Griffin is one of a select group of scientists that helped establish a UK lead in the technical development of instrumentation for submillimetre astronomy. He has been involved in most submillimetre instrument projects over the last three decades, including the Spectral and Photometric Imaging Receiver (SPIRE) camera on Herschel. Matt led a diverse international team to bring this project to fruition, encompassing 18 institutions on three different continents.

SPIRE represents a step change in capability. With the ground-based SCUBA camera, 20 nights of observing led to the detection of 5 galaxies at submillimetre wavelengths. With SPIRE, 6000 galaxies can be detected in 8 hours.

Matt Griffin thus receives the Jackson-Gwilt Medal for in particular his outstandingly successful work on SPIRE, an instrument that is transforming submillimetre astronomy.

Heartiest congratulations to Matt and, of course, to the rest of this year’s awardees!

After the RAS meeting it was time for dinner. Owing to a muddle with bookings The Athenaeum wasn’t available for this month’s RAS Club dinner so we dined instead in the unfamiliar surroundings of The Travellers Club, which is actually next door at 106 Pall Mall.Given the trials and tribulations of travelling with First Great Western, perhaps I should apply for honorary membership?

The room we had was smaller than usual, but cosy, and the staff were very friendly. The dinner wasn’t marvellous but as always there was no shortage of interesting conversation, some of it even relating to astronomy! I got grilled by a few people about what’s going on with STFC new consolidated grants system. I told everyone who asked everything I know about it, which didn’t break any confidentiality because I don’t know anything at all.

The table service was a bit slower than at the Athenaeum so it was quite late by the time we got onto the club business. The January dinner is the “Parish” dinner at which new members and, if necessary, new officers are elected by an amusingly arcane process. A few members had to leave  to catch trains before the business was completed but I stayed to the end at about 10.00pm,  placing (perhaps unjustified) confidence in  the 10.45 train from Paddington actually existing and getting there in time to get it.

I did get to Paddington in good time, and the train hadn’t been cancelled, but it was a bit late leaving.  It then apparently developed an unspecified “mechanical fault” which made for slow running. I got into Cardiff about 25 minutes late. No diversions on the way back – presumably the floods had subsided. Perhaps there’s an excuse for the chaos ensuing from the floods, but poor maintenance is surely entirely the fault of the train company.  Not a good day for First Great Western, especially when they’ve raised their already exorbitant fares for the new year..

Oh, and one other thing that’s not at all connected with anything else. As I walked back through Sophia Gardens from the station to my house in Pontcanna about quarter to two in the morning, I saw a fox hurtling across the path in front of me then vanishing into the trees. When I lived in Beeston (a suburb of Nottingham) I saw foxes very regularly, often in my own garden. Likewise even when I lived in Bethnal Green, in the East End of London. I was  quite surprised when I moved to my house in Cardiff, right next to Pontcanna Fields and Bute Park, that no foxes were to be seen despite the apparently more promising surroundings. I’ve now lived here for two and a half years and this is the first one I’ve ever spotted. I wonder why there are so few foxes in this area?


Cardiff inSPIREs Willetts

Posted in Politics, Science Politics, The Universe and Stuff with tags , , , , on July 9, 2010 by telescoper

The Minister for Universities and Science David Willetts’ important speech today at the Royal Institution in London has already attracted a considerable amount of comment and reaction. I haven’t really got time to comment on it in detail, but in between the expected warning of tough times ahead, it does contain a great deal of extremely interesting and thoughtful material, which I recommend you read if you’re interested in science policy.

Of particular interest to us here in the School of Physics & Astronomy at Cardiff University is that we get a specific mention for the wonderful work done by the Astronomical Instrumentation Group on the development of the SPIRE instrument on the Herschel Space Observatory.  Everyone’s chuffed about it, and delighted that the Minister chose to highlight this particular example of excellence.

In my speech at Birmingham University in May, I spoke of links between the academic and the vocational, the conceptual and the physical. We are not always good at this – we have world-class particle physicists at the Large Hadron Collider but sadly not many British engineers helped to build it. But there are other areas where these links between British science and technology are stronger. We not only have distinguished astronomers, but it was scientists and engineers at Cardiff University who produced the Spectral and Photometric Imaging Receiver for Herschel and Planck. This combination of scientific research and technological advance creates extraordinary dynamism, both intellectual and commercial. I see it as one of my tasks to strengthen these links.

OK, so I know SPIRE wasn’t for “Herschel and Planck” but the AIG was involved with instruments for both these missions so the point is well made anyway.

New light through a gravitational lens

Posted in The Universe and Stuff with tags , , , , on July 1, 2010 by telescoper

New data from the European Space Agency’s Herschel Space Observatory have just been released that shed new light on a well-known gravitational lens system involving the cluster Abell 2218. You can get more details and higher-resolution pictures from the STFC press release or from the dedicated Herschel Outreach Website, but I couldn’t resist putting this nice picture up.

Image Credit: ESA/SPIRE and HERMES Consortia

This triptych shows the region of sky around the massive galaxy cluster Abell 2218, as seen by the SPIRE instrument on Herschel and by the Hubble Space Telescope. On the far left, we have images at the three SPIRE wavelength bands (in the far-infrared part of the spectrum), while the centre image is a false-colour composite. The centre of the galaxy cluster is shown as a white cross-hair, while the large orange-yellow blob just below it is a much more distant galaxy.

On the far right you can see an optical image of the same cluster taken using the Hubble Space Telescope. Working at much shorter, optical wavelengths, the resolution here is much higher. This makes it possible to see the complicated pattern of  arcs caused by the distortion of light as it travels through the gravitational field of the cluster from background sources to the observer. The cluster acts as a gigantic optical system that produces magnified but warped images of very distant galaxies that lie behind it. It’s not designed to act as proper lens, of course, so the images it produces are deformed versions of the original, but they yield sufficient clues to work out the optical properties of the gravitational lens.

Clusters like this tend to contain lots of elliptical galaxies which are not bright in the SPIRE wavebands, so what we see with Herschel is very different from the Hubble view. What Herschel has  done in this particular case is  to reveal that this  gravitational lens produces at least one bright image in the far-infrared part of the spectrum. This is produced by a very distant galaxy which we probably would not have been able to see at all, even with Herschel, had it not been located fortuitously close to a perfect alignment with the optical axis of the Abell 2218 system. Although the image we see is distorted we can still learn a lot about the source that produced using the new data.

Clustering in the Deep

Posted in Bad Statistics, The Universe and Stuff with tags , , , , , , on May 27, 2010 by telescoper

I couldn’t resist a quick lunchtime post about the results that have come out concerning the clustering of galaxies found by the HerMES collaboration using the Herschel Telescope. There’s quite a lengthy press release accompanying the new results, and there’s not much point in repeating the details here, so I’ll just show a wonderful image showing thousands of galaxies and their far-infrared colours.

Image Credit: European Space Agency, SPIRE and HERMES consortia

According to the press release, this looks “like grains of sand”. I wonder if whoever wrote the text was deliberately referring to Genesis 22:17?

.. they shall multiply as the stars of the heaven, and as the grains of sand upon the sea shore.

However, let me take issue a little with the following excerpt from said press release:

While at a first glance the galaxies look to be scattered randomly over the image, in fact they are not. A closer look will reveals that there are regions which have more galaxies in, and regions that have fewer.

A while ago I posted an item asking what “scattered randomly” is meant to mean. It included this picture

This is what a randomly-scattered set of points actually looks like. You’ll see that it also has some regions with more galaxies in them than others. Coincidentally, I showed the same  picture again this morning in one of my postgraduate lectures on statistics and a majority of the class – as I’m sure do many of you seeing it for the first time –  thought it showed a clustered pattern. Whatever “randomness” means precisely, the word certainly implies some sort of variation whereas the press release implies the opposite. I think a little re-wording might be in order.

What galaxy clustering statistics reveal is that the variation in density from place-to-place is greater than that expected in a random distribution like that shown. This has been known since the 1960s, so it’s not  the result that these sources are clustered that’s so important. In fact, The preliminary clustering results from the HerMES surveys – described in a little more detail in a short paper available on the arXIv – are especially  interesting because they show that some of the galaxies seen in this deep field are extremely bright (in the far-infrared), extremely distant, high-redshift objects which exhibit strong spatial correlations. The statistical form of this clustering provides very useful input for theorists trying to model the processes of galaxy formation and evolution.In particular, the brightest objects at high redshift have a propensity to appear preferentially in dense concentrations, making them even more strongly clustered than rank-and-file galaxies. This fact probably contains important information about the environmental factors responsible for driving their enormous luminosities.

The results are still preliminary, but we’re starting to see concrete evidence of the impact Herschel is going to have on extragalactic astrophysics.

Herschel News

Posted in The Universe and Stuff with tags , , , , on January 17, 2010 by telescoper

I’ve been a bit slow to mention recent news about the European Space Agency‘s Herschel mission so this is by way of a quick update.

The first thing is to remind you that there was a big meeting of Herschel scientists in Madrid just before Christmas, which was attended by quite a number of Cardiff astronomers. It also happened to coincide with  less happy events. The purpose of this meeting was to share the preliminary results from the Science Demonstration Phase of Herschel’s operations. I did a quick post about some of the results, but didn’t have time to cover everything, which I still don’t. However, the complete set of presentations is now available online and I’d encourage you to sample some of the amazing results. Matt Griffin gave a nice overview of the key results at the RAS Ordinary Meeting just over a week ago.

You may recall that the Herschel telescope is fitted with three instruments:

  • The Photodetector Array Camera and Spectrometer (PACS)
  • The Spectral and Photometric Imaging REceiver (SPIRE)
  • The Heterodyne Instrument for the Far Infrared (HIFI)

The last of these instruments is basically a high-resolution spectrometer which, among other things will be great for detecting spectral lines from molecules, including good old H2O. In fact here’s a nice example of a water line seen in a comet

The problem is that HIFI has actually been switched off for quite a while – 160 days in fact – after a fault developed in its power supply. There is a backup power-supply, of course, but the engineers didn’t want to switch it over until they had figured out what had gone wrong, which took quite a while.  However, last Thursday, the HIFI instrument was switched back on and is now working fine. The full story can be found here. It was also covered quite a bit in the general media, including  the BBC.

While HIFI was offline, the calibration and verification of PACS and SPIRE went ahead at a good speed and now HIFI will have to catch up which has meant a bit of juggling around with schedules but, other than that, it’s all systems go…

Finally, I’ll just point out in case you didn’t know or have forgotten, that the Herschel Mission has its own wordpress blog, which is regularly updated  and is well worth checking out.

Astronomy Look-alikes, No. 6

Posted in Astronomy Lookalikes with tags , , , , , on January 1, 2010 by telescoper

Staying close to home in Cardiff, I should point out for those who were previously unaware, that our very own Matt Griffin had another career before becoming Principal Investigator for the SPIRE instrument on Herschel. His most famous acting role was as the seedy landlord, Rigsby, in the 1970s situation comedy Rising Damp.

Professor Matt Griffin


Interesting Times

Posted in Biographical, Science Politics, The Universe and Stuff with tags , , , on December 14, 2009 by telescoper

The next few days promise to be extremely interesting, although there is more than a hint of the Chinese Curse in that statement! Today is the day of our annual departmental Christmas Lunch. That’s not itself the subject of any kind of curse, but if last year’s is anything to go by it may take several days to recover from it. I’m preparing myself for it mentality as I write.

Tomorrow, however, 15th December, is the date of the next meeting of the Council of the Science and Technology Facilities Council. On their agenda is the programme of cuts that is proposed as a result of the recent prioritisation exercises initiated to try to find a way out of their ongoing funding crisis. This programme has been through various committees before reaching the Council and, if the Council accepts it, the plans will be unveiled at a press conference on Wednesday 16th (at 2pm) and those about to die will be informed immediately. I’ll try to post a summary on here as soon as I get the facts.

I don’t have any particular inside information who is going to get the chop, but rumour suggests that there will be cuts right across the board. I think it’s going to be very grim news indeed, especially because there is an additional £600 million of savings to be found over the next few years on top of the current shortfall. It’s bound to be a terrible Christmas for those about to find out their contracts are being axed, and no happy New Years for a while either.

I’m not privy to the Council discussions or to the recommendations that have been passed to them so it’s not my place to say what they should do. However, in the unlikely event that anyone from STFC Council is reading this, I hope he/she at least bears in mind that it is not – or at least it shouldn’t be – the job of the Council simply to rubber stamp everything that is passed before it. I wonder, though, if the current Council has the guts to pass a vote of no confidence in the STFC Executive? I doubt it, because there’s been no reason to have confidence in them for the past two years and no such motion has been carried.

Ironically, later in the week there’s going to be a big jamboree in Madrid, at which the initial results of the Science Demonstration Phase of Herschel will be announced. Quite a few of the Cardiff crowd are going along and will be presenting some of the wonderful things that they’ve been working on for the past few weeks. I’ve seen quite a lot of the data from the SPIRE instrument and it’s truly amazing. At least there’s some (infrared) light among the darkness. However, it’s all covered by an ESA press embargo until Wednesday…

Spire Spectra

Posted in The Universe and Stuff with tags , , , , , , on November 27, 2009 by telescoper

OK, so it turns out I lied about not posting today. It’s not because I’m a dishonest professor, though. It’s just that I couldn’t resist drawing your attention to the new results that have just been released by the European Space Agency. To whet your appetite, have a shufty at this exquisite far infrared spectrum of the star VY Canis Majoris taken using the SPIRE instrument for which Cardiff is the lead institute.

VY Canis Majoris (VY CMa) is a red hypergiant, an enormous evolved star located in the constellation Canis Major. With a radius 2600 times that of the Sun, it is the largest known star and it is also one of the most luminous stars known. It is located about 4900 light years away from Earth, has a luminosity in excess of 100,000  solar luminosities, and a mass in the range 30-40 solar masses.

The shell of gas it has ejected displays a complex structure, the so-created circumstellar envelope is among the most remarkable chemical laboratories known in the universe, creating a rich set of organic and inorganic molecules and dust species. Through stellar winds, these inorganic and organic compounds are injected into the interstellar medium, from which new stars orbited by new planets may form. Most of the carbon supporting life on planet Earth was probably made by this kind of evolved star. VY CMa is close to the end of its life and could explode as a supernova at any time.

Spectroscopic results may be a bit less photogenic than pretty pictures, but they often yield much more physically relevant information than simple images. As I’ve mentioned before, it is in spectroscopy where we find the difference between astronomy and astrophysics (or, less politely, between stamp collecting and science).  In this case the spectrum gives a detailed breakdown of the chemical mixture present in the matter ejected by this star.

You can find other stunning examples of Herschel’s infrared spectroscopic capabilities here and you can read more about the involvement of Cardiff astronomers in these stunning new science results on our own pages here.

There’s also a story on the BBC Website.

The Milky Way in a New Light

Posted in The Universe and Stuff with tags , , , , , on October 2, 2009 by telescoper

I note that the Herschel mission now has its own blog, so I no longer have to try to remember to put all the sexy images on here. However, at the end of a worrying week for UK astronomy, I thought it would be a good idea to put up one of the wonderful new infra-red images of the Milky Way just obtained from Herschel. This is the first composite colour picture made in “parallel mode”, i.e. by using the PACS and SPIRE instruments together. Together the two instruments cover a wavelength range from 70 to 500 microns. The resulting image uses red to represent the cooler long-wavelength emission (seen by SPIRE) and bluer colours show hotter areas. The region of active star formation shown is close to the Galactic plane; detailed images such as this, showing the intricate filamentary structure of the material in this stellar nursery, will help us to understand better how what the complex processes involved in stellar birth.

Sensational SPIRE

Posted in The Universe and Stuff with tags , on July 10, 2009 by telescoper

As I promised a few days ago, the “first light” images from the Herschel instrumment SPIRE have now been released (along with news of the other instruments on Herschel)  and I have to say they’re pretty spectacular! I’m told that these pictures are much better than anyone expected at this stage because Herschel as a whole still hasn’t finished its calibration and other preparations it needs to do before commencing as an observatory proper.

Here, for example, is an image of the spiral galaxy M74 (also known as NGC 628) as shown by SPIRE and by the American Spitzer satellite, which was launched a few years ago. This image is taken at 250 microns, which is further into the infrared than the Spitzer image (160 microns), but has higher resolution owing to Herschel’s bigger mirror (3.5m). The SPIRE instrument is also much more sensitive than Spitzer so by a combination of these effects the detail this image reveals is really stunning.

What you’re actually seeing in this image is long-wavelength radiation emitted by dust which has been heated up by stars in the galaxy. The dust obscures the optical light from the stars but they leave clues to their existence in the infrared light the dust gives off. You can see dark lanes in the optical image here where the dust is absorbing the starlight.

Here is M74 again, but shown with two additional infrared “colours” (at 350 and 500 microns). By making observations like this at different wavelengths SPIRE can reveal information about the spectrum and hence temperature of the dust emission.

Congratulations to the Cardiff SPIRE team for a stunning success. If these images are any guide to the quality of data Herschel is going to be producing over the next few years then we’re all in for a treat!