SPIRE first light images arrive!


The news is out, on the BBC and elsewhere, with the full coverage from ESA – first light results from all three of Herschel’s instruments, including the one I work on – SPIRE.

Image of the galaxy M66 taken with SPIRE at a wavelength of 250 microns compared to Spitzer image at 160 microns.

Image of the galaxy M66 taken with SPIRE at a wavelength of 250 microns compared to Spitzer image at 160 microns.

The images are superb! You can see far more structure in these images than in the best previously available even though SPIRE’s are at longer wavelengths. You can see structure in the dust distribution in these galaxies and, by comparing the three different colours SPIRE observes in, you can get some idea of the temperature distribution of the dust.

SPIRE image of M74

Also, the faint background blobs in these images are real, as they’re present at all three SPIRE wavelengths. These are background dusty galaxies which we expect SPIRE will be able to detect in great numbers. This promise is now fulfilled marvelously in the first images we’ve taken. These are the galaxies responsible for the Cosmic Infrared Background which encompasses half the energy generated in the universe since the Big Bang. It’s made up of light emitted by stars, and accreting supermassive back holes, which has been absorbed by dust and reradiated at these long far-IR wavelengths. It is the hidden history of the universe, something we have had little access to before now, but which SPIRE will now help us to understand in detail.

M74 images in all 3 SPIRE bands

M74 images in all 3 SPIRE bands

HIFI, the high resolution spectrometer, also has released its first spectra, showing strong emission lines from gas involved in star formation in the DR21 molecular cloud.

Herschel was only launched about 7 weeks ago, and these observations are just a first quick look at what the instruments can do. There is a lot more tuning, calibration and refinement to be done before we can do real quantitative science with these instruments. For that reason to get decent data on anything at this stage is quite amazing. To get data of the quality seen in the SPIRE images, the PACS images you can find below and in the HIFI spectra is absolutely astounding.

Herschel really is going to bring a new era to far-IR astronomy!

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24 Responses to “SPIRE first light images arrive!”

  1. Eats Wombats Says:

    Well, it looks great but the BBC news story says, if I understand it correctly, that the telescope will last until 2013. Is this true? Is this value for money? (compared to, er, Hubble)

  2. Dave Says:

    The thing that limits Herschel’s lifespan is the use of liquid helium to keep the instruments cold. This gradually boils off and, since there’s no chance of servicing the satellite at L2, it dies. The lifespan should be at least 3.5-4 years, but might be longer (we’ll get a better idea as commissioning progresses and everything gets fully cold). This compares to the previous generation of IR satellite from ESA, called ISO, which lasted about 2 years but had a much much smaller mirror (85cm compared to Herschel’s 3.5m).

    This is as good as the engineering can do at the moment as there’s currently no way to do the cooling without having expendable liquid gases. The next generation far-IR mission currently being planned – SPICA, a Japanese led mission which we hope will include an ESA contribution – will use closed cycle coolers so there will be no expendables.

    As to value for money, it’s worth noting that Herschel as a whole probably cost a lot less than the recent Hubble servicing mission. A Shuttle launch alone puts you into 500 billion dollar territory before anything else is accounted for. Herschel as a whole cost about 850 million Euros.

  3. J.S. Grasso Says:

    The images are fantastic. Is there a significant difference between microwaves and “far infrared”?

    • Dave Says:

      Yes, and thanks for the question!

      In the microwaves you’d primarily be seeing ‘non-thermal’ emission, coming, for example, from electrons scattering off each other or in strong magnetic fields. In the far-IR you’re primarily seeing thermal emission from cool (about 50K) dust. You need to look at both things understand a given object. Until now we’ve had only a very coarse view of the far-IR. But Herschel changes that.

  4. RoverDaddy Says:

    A shuttle launch certainly doesn’t cost 500 Billion dollars. NASA’s web site says the average cost is 450 Million, but I would be willing to believe it’s a bit more.

  5. Kevin Says:

    Dave: I think you meant millions, not billions. The average cost of a space shuttle launch according to NASA is around $450 million.

    • Dave Says:

      Yes – mea culpa. I got caught between saying half a billion and 500 million and munged them together.

      Apologies all round!

  6. Old Far Seeing Art Says:

    Dave said: “A Shuttle launch alone puts you into 500 billion dollar territory before anything else is accounted for. Herschel as a whole cost about 850 million Euros.”

    Wikipedia says:
    “Per-launch costs can be measured by dividing the total cost over the life of the program (including buildings, facilities, training, salaries, etc) by the number of launches. With 115 missions (as of 6 August 2006), and a total cost of $150 billion ($145 billion as of early 2005 + $5 billion for 2005,[19] this gives approximately $1.3 billion per launch. ”

    Google says:
    850 Euros = 1 184.985 U.S. dollars

    I say: check your numbers

    • Dave Says:

      I say: check your numbers

      Well said – my only defense is that I was being dragged off to dinner.

      The numbers you give are even more than I thought for a shuttle launch. This means that just launching a servicing mission to Hubble, before you pay for any of the payload, is more expensive than Herschel (though given the uncertainties on both sides it’s probably best to say that they’re about the same). I didn’t realize shuttle was so expensive – thanks for this!

  7. Abhijit Says:

    Wasnt it possible to use closed cycle coolers for Herschel….by the way how is it exactly possible to have a cooler without cryogenic fluids….

    • Dave Says:

      As with all space missions, you have to design the system to use proved reliable technologies. This means that you’re usually stuck with systems that are 10 years old at the time of flight. Closed cycle coolers for space have only come along very recently so none were available at the time Herschel was designed. This isn’t the case with SPICA which will launch in about 8-10 years time if it is selected.

      As to how the coolers work, in most cases there are cryogenic fluids being used, but these just cycle around the device, as is the case with your fridge at home, so they are not expended over time.

  8. Dumb Scientist Says:

    First of all, congrats on the functioning telescope! This is an amazing achievement on the part of the ESA. All of Europe- indeed all of the human race- should be proud of what you’ve accomplished.

    I’m curious, though. How do you know the blobs are background galaxies rather than, say, foreground stars or star clusters that are either in our galaxy or stranded in intergalactic space between M74 and the Milky Way? Are there already spectroscopic measurements to measure the redshifts? Is this a statistical argument based on the size of the blob versus the expected distribution of intergalactic stragglers?

    Anyway, thanks for sharing the first images so quickly. That way people like me get to ask inane questions. πŸ™‚

    • Dumb Scientist Says:

      Hmm… according to a Slashdot poster, the dust blobs I was confused about are only at 50K. So, not stars… which probably means their angular size implies that they really are in the background. Is that correct?

      • Dave Says:

        That poster was actually me πŸ™‚

        Most of the background sources are unresolved which does indeed suggest that they’re rather further away than the foreground spiral galaxies. Determining the nature of these objects is in fact one of the major goals of Herschel so it’s very early days yet for saying exactly what’s going on, but you’re broadly right here.

        Watch this space for more information on these objects as we start to get real science observations!

  9. Top Posts « WordPress.com Says:

    […] SPIRE first light images arrive! The news is out, on the BBC and elsewhere, with the full coverage from ESA – first light results from all three […] […]

  10. HArry Johnston Says:

    In this context, the capital costs of the shuttle program shouldn’t be counted, only the incremental cost of conducting the particular mission, or alternately, the opportunity cost of not doing another mission. So the figure provided by Old Far Seeing Art is too high.

    However, your main point is well taken – Herschel is definitely value for money.

  11. Liam Proven Says:

    Nice one, Dave. My hearty congratulations.

  12. Dee Doe Says:

    Thanks for the post Dave and congratulations to the Herschel team – a wonderful result already – keep tuning, calibrating and refining – it can only get better! πŸ™‚

  13. Zortron Says:

    Everything goes round and round,,,round and round,,molecles,hurricanes,toilet water ,suns,planets most of them,solar systems,galaxies,,magnetic fields,universes????,my head….

  14. 2010 in review « The Herschel Space Observatory Says:

    […] SPIRE first light images arrive! July 200923 comments 5 […]

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