Disturbing the Universe

David L Clements, science and science fiction


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Infrared Astronomy Linkfest!

As the publication date for my Infrared Astronomy book gets ever closer (I am told it was sent to the printers this week) I’ve made some major updates to the webpage accompanying the book, which can be found here.

And if you have any links relevant to infrared astronomy that you think should be added, please list them in the replies to this post. Thanks!

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Pythagoras’ Trousers and Herschel

Several of us were interviewed by Chris North at a recent Herschel meeting about what we thought were the highlights of the mission. This was broadcast on Radio Cardiff on 19th May as part of the Pythagoras’ Trousers programme. I don’t know where they got that title but at least they know how to use apostrophes.

You can now hear this section of the programme here.

At the end of the segment, starting at about 17 minutes in, is an attempt to explain the Herschel mission in ordinary plain language, using a script by Jon Brumfitt & Leo Metcalfe read by me. I’m glad that’s all clear now.


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Astronomy Valentines

There was a meme going round twitter yesterday for scientist valentines. I ended up committing a couple which seemed to go down quite well, so I thought I would inflict them on you via my blog, just in case you missed them. You have been warned:

R band is red,
B band is blue,
I can’t see I,
and neither can you.

And:

I band is red,
J band is redder,
If you think K comes next
You’re not an infrared astronomer
Both are inspired by astronomical filter systems and, in the latter case, the difficulty with the alphabet that my colleagues in infrared astronomy seem to have.
Of course someone has since claimed to be able to see in the I band, but there are mutants everywhere.


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Press Release: Four new galaxy clusters take researchers further back in time

I have a press release out today! Below is the text from the release from Imperial. So far it seems to have been picked up by:

The Daily Mail

The Financial Express

The Economic Times

Phys.Org

scientias.nl (in Dutch)

and there may be more to come.

Not sure what to think about the Daily Mail entry – it’s not my favourite paper, but, as a colleague said, ‘if your piece is next to “Lauren Goodger shows off the results of her new boob job in unflattering sheer dress at charity event” and “What happened to natural beauty, Kim? Kardashian overdoes her look with thick, heavy make-up arriving at Khloe’s house” you’re certainly reaching new audiences.’

News: science

Imperial College London

Four new galaxy clusters take researchers further back in time

by Gail Wilson12 February 2014

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Four unknown galaxy clusters each potentially containing thousands of individual galaxies have been discovered some 10 billion light years from Earth.

An international team of astronomers, led by Imperial College London, used a new way of combining data from the two European Space Agency satellites, Planck and Herschel, to identify more distant galaxy clusters than has previously been possible. The researchers believe up to 2000 further clusters could be identified using this technique, helping to build a more detailed timeline of how clusters are formed.

– Dr Dave Clements

Study author

Galaxy clusters are the most massive objects in the universe, containing hundreds to thousands of galaxies, bound together by gravity. While astronomers have identified many nearby clusters, they need to go further back in time to understand how these structures are formed. This means finding clusters at greater distances from the Earth.

The light from the most distant of the four new clusters identified by the team has taken over 10 billion years to reach us. This means the researchers are seeing what the cluster looked like when the universe was just three billion years old.

Lead researcher Dr David Clements, from the Department of Physics at Imperial College London, explains: “Although we’re able to see individual galaxies that go further back in time, up to now, the most distant clusters found by astronomers date back to when the universe was 4.5 billion years old. This equates to around nine billion light years away. Our new approach has already found a cluster in existence much earlier than that, and we believe it has the potential to go even further.”

The clusters can be identified at such distances because they contain galaxies in which huge amounts of dust and gas are being formed into stars. This process emits light that can be picked up by the satellite surveys.

Galaxies are divided into two types: elliptical galaxies that have many stars, but little dust and gas; and spiral galaxies like our own, the Milky Way, which contain lots of dust and gas. Most clusters in the universe today are dominated by giant elliptical galaxies in which the dust and gas has already been formed into stars.

“What we believe we are seeing in these distant clusters are giant elliptical galaxies in the process of being formed,” says Dr Clements.

Observations were recorded by the Spectral and Photometric Imaging Receiver (SPIRE) instrument as part of Herschel Multi-tiered Extragalactic Survey (HerMES). Seb Oliver, Head of the HerMES survey said: “The fantastic thing about Herschel-SPIRE is that we are able to scan very large areas of the sky with sufficient sensitivity and image sharpness that we can find these rare and exotic things.  This result from Dr. Clements is exactly the kind of thing we were hoping to find with the HerMES survey”

The researchers are among the first to combine data from two satellites that ended their operations last year: the Planck satellite, which scanned the whole sky, and the Herschel satellite, which surveyed certain sections in greater detail. The researchers used Planck data to find sources of far-infrared emission in areas covered by the Herschel satellite, then cross referenced with Herschel data to look at these sources more closely. Of sixteen sources identified by the researchers, most were confirmed as single, nearby galaxies that were already known. However, four were shown by Herschel to be formed of multiple, fainter sources, indicating previously unknown galaxy clusters.

The team then used additional existing data and new observations to estimate the distance of these clusters from Earth and to determine which of the galaxies within them were forming stars. The researchers are now looking to identify more galaxy clusters using this technique, with the aim of looking further back in time to the earliest stage of cluster formation.

The research involved scientists from the UK, Spain, USA, Canada, Italy and South Africa. It is published in the Monthly Notices of the Royal Astronomical Society.


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Hawaiian Weather

And the weather report from Hawaii today is: temperatures -5 to -7, windspeed 60 to 100 mph with gusts up to 120 mph. That means with windchill it would feel like -28. Eat your heart out Edmonton!

Those are the real figures, but that’s because I’m on the top of Mauna Kea failing to get any observing done because of the wind.

It’s an astronomer’s life.

In the meantime I’m carrying on work on the Infrared Astronomy book. Today I learned that Titan has a methane cycle the way the Earth has a hydrological cycle. Maybe it should be called the mythalogical cycle?


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Planck is dead: Long Live Planck!

The Planck spacecraft was shut down, sent termination software to prevent any accidental restart, and has been left to drift in an Earth trailing graveyard orbit for the foreseeable, and very long term, future.

The spacecraft is dead, but the data lives on.

And so both of the missions I’ve been working on since 2001, and been at least peripherally involved with since the mid 1990s, are now over. Rather sad really.


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Heading down

Last night was my last night on the mountain for my current observing run at the SMA. As we left the telescope last night we were greeted by a wonderful halo around the moon, which was up at the zenith. I didn’t have a camera with me but it looked at bit like the image that can be found here, though obviously without the trees.

Next stop sea level and a return to a normal supply of oxygen!