Archive for European Space Agency

The Tenth Anniversary of the Herschel/Planck Launch

Posted in Biographical, Cardiff, The Universe and Stuff with tags , , on May 14, 2019 by telescoper

A little birdie told me (via a tweet) that today is the 10th anniversary of the launch of the ESA Planck and Herschel satellite missions. Can it really be so long ago?

Anyway, both were superbly successful and both involved many friends and former colleagues from Cardiff and elsewhere, so I thought I’d reblog this post which I wrote on the day of the launch (on May 14 2009)….

In the Dark

The Big Day has finally arrived!

I’ve managed to submit my paper to the journal and the ArXiv before the little shindig we’ve been planning for the Planck and Herschel launch gets under way at 1pm. Business as usual so far, though.

Strangely, I haven’t managed to get nervous yet, although I have to say  there are many anxious faces around the department. I just keep telling people how much simpler their life is going to be if it all goes wrong, without all that messy and unnecessarily complicated data to deal with. It bothers me sometimes that I don’t often get nervous expect when watching sport. Mind you, being  a Newcastle United supporter probably makes me more nervous more often than most people.

Anyway, at times like this a  stiff upper lip is obviously called for. Anyone who cracks now is clearly not officer material. There’ll be plenty of…

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Nature After Planck…

Posted in Maynooth, The Universe and Stuff with tags , , , , , , on July 24, 2018 by telescoper

After last week’s short update about the last tranche of papers from the European Space Agency’s Planck Mission it’s time for another short update about a piece in Nature (by David Castelvecchi) that explains how researchers are moving to smaller projects studying different aspects of the cosmic microwave background.

In the spirit of gratuitous self-promotion I should also mention that there’s a little quote from me in that piece. My comment was hardly profound, but at least it gets Maynooth University a name check…

Much of Davide’s piece echoes discussions that were going on at the meeting I attended in India  last October, but things have moved on quite a bit since then at least as far as space experiments are concerned. In particular, the proposed Japanese mission Litebird has been shortlisted for consideration, though we will have to wait until next year (2019) at the earliest to see if it will be selected. An Indian mission, CMB-Bharat, has also emerged as a contender.

While the end of Planck closes one chapter on CMB research, several others will open. These are likely to focus on polarization, gravitational lensing and on cosmic reionization rather than refining the basic cosmological parameters still further.

Planck’s Last Papers

Posted in The Universe and Stuff with tags , , , , on July 17, 2018 by telescoper

Well, they’ve been a little while coming but just today I heard that the final set of a dozen papers from the European Space Agency’s Planck mission are now available. You can find the latest ones, along with the all the others, here.

This final `Legacy’ set of papers is sure to be a vital resource for many years to come and I can hear in my mind’s ear the sound of cosmologists all around the globe scurrying to download them!

I’m not sure when I’ll get time to read these papers, so if anyone finds any interesting nuggets therein please feel free to comment below!

Planck wins the Gruber Prize (and the Shaw Prize)

Posted in Science Politics, The Universe and Stuff with tags , , on May 13, 2018 by telescoper

I forgot to mention last week that the 2018 Gruber Prize for Cosmology has been awarded to the Planck team, and its Principal Investigators Nazzareno Mandolesi and Jean-Loup Puget.

For more information about the award and the citation, see here.

This annual prize is worth $500,00; the two PIs will get $125,000 each and the rest divided among the team. I’m not sure whether this means the Planck Science Team (whose membership is listed here or the entire Planck Collaboration (which numbers several hundred people) but regardless of whoever gets the actual dosh, this award provides a good excuse to send congratulations to everyone who worked on this brilliant and highly successful mission!

 

UPDATE: 14th May 2018. Jean-Loup Puget has also been awarded the Shaw Prize for Astronomy.

Gaia’s Second Data Release!

Posted in The Universe and Stuff with tags , , , on April 26, 2018 by telescoper

It seems like only yesterday that I was blogging excitedly about the first release of data (DR1) from the European Space Agency’s Gaia Mission. In fact it was way back in 2016! Anyway, yesterday came another glut of Gaia goodness in the form of the second release of data, known to its friends as DR2.

In case you weren’t aware, Gaia is an ambitious space mission to chart a three-dimensional map of our Galaxy, the Milky Way, in the process revealing the composition, formation and evolution of the Galaxy. Gaia will provide unprecedented positional and radial velocity measurements with the accuracy needed to produce a stereoscopic and kinematic census of about one billion stars in our Galaxy and throughout the Local Group. This amounts to about 1 per cent of the Galactic stellar population.

You can find links to all the DR2 science papers here, a guide to how to use the data here, and of course a link to the full Gaia Archive here.

Here’s a (brief!) list of the contents of DR2:

  • The five-parameter astrometric solution – positions on the sky (α, δ), parallaxes, and proper motions – for more than 1.3 billion (109) sources, with a limiting magnitude of G = 21 and a bright limit of G ≈ 3. Parallax uncertainties are in the range of up to 0.04 milliarcsecond for sources at G < 15, around 0.1 mas for sources with G=17 and at the faint end, the uncertainty is of the order of 0.7 mas at G = 20. The corresponding uncertainties in the respective proper motion components are up to 0.06 mas yr-1 (for G < 15 mag), 0.2 mas yr-1 (for G = 17 mag) and 1.2 mas yr-1 (for G = 20 mag). The Gaia DR2 parallaxes and proper motions are based only on Gaia data; they do no longer depend on the Tycho-2 Catalogue.
  • Median radial velocities (i.e. the median value over the epochs) for more than 7.2 million stars with a mean G magnitude between about 4 and 13 and an effective temperature (Teff) in the range of about 3550 to 6900 K. This leads to a full six-parameter solution: positions and motions on the sky with parallaxes and radial velocities, all combined with mean G magnitudes. The overall precision of the radial velocities at the bright end is in the order of 200-300 m s-1 while at the faint end the overall precision is approximately 1.2 km s-1 for a Teff of 4750 K and about 2.5 km s-1 for a Teff of 6500 K.
  • An additional set of more than 361 million sources for which a two-parameter solution is available: the positions on the sky (α, δ) combined with the mean G magnitude. These sources have a positional uncertainty at G=20 of about 2 mas, at J2015.5.
    G magnitudes for more than 1.69 billion sources, with precisions varying from around 1 milli-mag at the bright (G<13) end to around 20 milli-mag at G=20. Please be aware that the photometric system for the G band in Gaia DR2 is different from the photometric system as used in Gaia DR1.
  • GBP and GRP magnitudes for more than 1.38 billion sources, with precisions varying from a few milli-mag at the bright (G<13) end to around 200 milli-mag at G=20.
  • Full passband definitions for G, BP and RP. These passbands are now available for download.
  • Epoch astrometry for 14,099 known solar system objects based on more than 1.5 million CCD observations. 96% of the along-scan (AL) residuals are in the range -5 to 5 mas, and 52% of the AL residuals are in the range of -1 to 1 mas. The transit observations are part of Gaia DR2 and have also been delivered to the Minor Planet Center (MPC).
  • Subject to limitations (see below) the effective temperatures Teff for more than 161 million sources brighter than 17th magnitude with effective temperatures in the range 3000 to 10,000 K. For a subset of about 87 million sources also the line-of-sight extinction AG and reddening E(BP-RP) are given and for a part of this subset (around 76 million sources) the luminosity and radius are available as well.
  • Classifications for more than 550,000 variable sources consisting of Cepheids, RR Lyrae, Mira and Semi-Regular Candidates as well as High-Amplitude Delta Scuti, BY Draconis candidates, SX Phoenicis Candidates and short time scale phenomena.
  • Planned cross-matches between Gaia DR2 sources on the one hand and Hipparcos-2, Tycho-2, 2MASS PSC, SDSS DR9, Pan-STARRS1, GSC2.3, PPM-XL, AllWISE, and URAT-1 data on the other hand.

There’s much more to Gaia than pictures, but here’s a map of the stars in our galaxy to give you an idea:

I remember first hearing about Gaia about 17 years ago when I was on a PPARC advisory panel and was immediately amazed  by the ambition of its objectives. As I mentioned above, Gaia is a global space astrometry mission, which will make the largest, most precise three-dimensional map of our Galaxy by surveying more than a billion stars. In some sense Gaia is the descendant of the Hipparcos mission launched in 1989, but it’s very much more than that. Gaia monitors each of its target stars about 70 times over a five-year period. It is expected to discover hundreds of thousands of new celestial objects, such as extra-solar planets and brown dwarfs, and observe hundreds of thousands of asteroids within our own Solar System. The mission is also expected to yield a wide variety of other benefits, including new tests of the  General Theory of Relativity.

For the brighter objects, i.e. those brighter than magnitude 15, Gaia  measures their positions to an accuracy of 24 microarcseconds, comparable to measuring the diameter of a human hair at a distance of 1000 km. Distances of relatively nearby stars are measured to an accuracy of 0.001%. Even stars near the Galactic Centre, some 30,000 light-years away, have their distances measured to within an accuracy of 20%.

It’s an astonishing mission that will leave an unbelievably rich legacy not only for the astronomers working on the front-line operations of Gaia but for generations to come.

Ariel to Fly

Posted in The Universe and Stuff with tags , , , , on March 23, 2018 by telescoper

All hail, great master! Grave sir, hail! I come
To answer thy best pleasure. Be ‘t to fly,
To swim, to dive into the fire, to ride
On the curled clouds, to thy strong bidding task
Ariel and all his quality.

The Tempest, Act I, Scene 2.

It’s nice to be able to pass on a bit of good news for the good folk of the Astronomy Instrumentation Group here in the School of Physics & Astronomy at Cardiff University.

The ARIEL mission has been given the green light by the European Space Agency and will launch sometime around 2028. It will produce the first ever large-scale survey of the atmospheric chemistry of planets outside our solar system. Ariel will extract the chemical fingerprints of the gases in the atmospheres of over 1000 exoplanets, as well as capturing information about the temperatures and pressures in their atmospheres and the presence of clouds.

Whenever I read of exciting news from the field of exoplanet research – which happens quite frequently nowadays – it reminds me that when I started my graduate studies (in 1985) the field didn’t really exist. Now it’s one of the biggest and most active areas of astronomy! Another thing that makes me feel a bit of a dinosaur is that when Ariel actually launches I’ll be 65…

As with all such missions, a large international collaboration will be involved in Ariel, and much of the detail of who will do what is yet to be worked out, but Cardiff scientists will be providing detailed computer simulations of the Ariel satellite and its instruments, ensuring that the scientific observations can be carefully planned and the resulting data can be analysed correctly. The team will also be involved in the ground segment after launch, interpreting the data from the observations to characterise the atmospheres of the exoplanets. The Principal Investigator of the whole mission is Professor Giovanna Tinetti of University College, London, who I see regularly at dinner with the RAS Club.

Head Irishman of the School, Matt Griffin, who will himself is quoted in the news item as saying

The decision to select the Ariel mission demonstrates the scientific vision and ambition of ESA, and it’s the start of a great adventure for everyone involved. This is a mission that will hugely advance our understanding of the nature of planets and of our place in the Universe, and at Cardiff we are very much looking forward to our participation in the project.

The launch date of 2028 is some way off but space missions are exceedingly complicated things and there’s a lot to do in the next decade or so until Ariel finally flies. Hopefully neither swimming, nor diving into fire nor riding on the curled clouds will be involved, but the scientific quality is something of which we can be very confident.

Congratulations to everyone involved in getting this mission selected and best wishes to all those involved in Cardiff and elsewhere!

Maynooth joins the Euclid Community

Posted in Maynooth, The Universe and Stuff with tags , , , on January 10, 2018 by telescoper

There’s a nice webpage showing all the institutions around the world who belong to the consortium behind the European Space Agency’s Euclid Mission. Here’s a screen grab that shows all the logos of all the institutions involved in this very large Consortium:

There are so many that it’s hard to see them all, but if you look very closely about half way down, among the Ms, you will see Maynooth University among them. This is the first institution in Ireland to have joined the Euclid Consortium and it has just been officially added thanks to yours truly moving there later this year. Ireland is a member state of the European Space Agency, by the way.