Fermi sees the gamma-ray sky for the first time

By Phil Plait | August 26, 2008 5:42 pm

Two cool things:

1) NASA’s Gamma-ray large Area Space Telescope, neé GLAST, is now called Fermi! It was named after Enrico Fermi, a famous physicist who accomplished much in his life, including creating the first sustained nuclear chain reaction, proposing how cosmic rays — subatomic particles with ferocious energy — attained their incredible speeds, and having his name attached to the Fermi Paradox (OK, that’s not really science, but still– he asked, if aliens are common in the Universe, where are they?). When I worked on GLAST we speculated that might be the name eventually chosen, but I thought it unlikely since Fermi already has a lab named after him in Illinois. Guess I was wrong.

2) GLAST Fermi (nuts, guess I’ll have to get used to that) has seen first light! The image is below, marked with some bright sources.

Fermi’s first light image of the gamma-ray sky

Fermi only sees super-high-energy gamma rays, which are photons of light just like the ones we see (visible light photons), but with millions or even billions of times the energy. Only very violent or energetic objects emit them: exploding stars, matter swirling around black holes, pulsars ("dead" stars with incredibly strong magnetic fields), and the like. In the image, there are several obvious sources, including the center of our Galaxy (where a four-million solar mass black hole resides), a few other galaxies with similar black holes, pulsars, and the plane of the Milky Way (where sources merge into a blurry glow).

Interestingly, there is a background glow everywhere. That is one of the things Fermi is meant to look into: are those individual distant galaxies all blurring together, or an actual diffuse glow caused by some unknown source? We may soon know.

Fermi also has a Burst Detector Monitor (hmm, which used to be called the GBM for "GLAST Burst Detector Monitor", so now it must be the FBD), which will see the flash of energy from gamma-ray bursts, the most violent events in the Universe. In the first month of operation, the FBD saw a burst roughly every day! This is fantastic news; it means we’ll get even better statistics on these distant and creepy events. I’d go into detail, but (obsplug) my book on all this comes out in a couple of months, and it’ll have more detail than you want. Trust me. If you’re impatient, searching the blog might help.

As regular readers know, I worked on education and public outreach for Fermi back when it was still GLAST, so it’s very exciting to see it not only flying, but performing so well! Seeing the first light image is very, very satisfying. And I’m very happy for all the scientists and engineers who worked on it. Congratulations to everyone!


Comments (43)

  1. I look forward to your book then on this subject. Seems like there is a lot going on up there. Of course, the tinfoil hat crowd will make some shoddy “docudrama” about one of these bursts happening in our back yard. I hope you address that in your book so I have some reference material.

  2. Marshall Roth

    I listened to the press conference today, and I think Steve Ritz summed it up quite nicely: Fermi has seen in a few days what it took the EGRET to see in 5 years. This opens up a huge area of study on the day to day variability of many of these sources (and the ability to make nice movies :-) ).

    Fermi also has half of the types of matter in the universe named after him as well; why not Villard?

  3. I like “Fermi” much better than “GLAST”. I know in the long run the science is what’s important and not the name. However, GLAST seemed so utilitarian and unimaginative.

    Glad to see it’s working properly, regardless of the name!

  4. Tod

    So, what’s a “blazar?” A blazing hot (radiation-wise) stellar object? I googled it and came up with nothing.

  5. Hugo

    Anyone know if Fermilab also derives it’s name from the above-mentioned Enrico Fermi?

  6. Davidlpf

    Hugo yes it was.

    But of course everyone knows that the high energy particles it detects is just synchrotron radiation. :-)
    (Davidlpf now runs and hides)



    So, what’s a “blazar?” A blazing hot (radiation-wise) stellar object? I googled it and came up with nothing.

    Try this: http://arxiv.org/abs/0711.3524v1

  8. KC

    I just wish NASA would decide these things well in advance…naming a spacecraft and then renaming after launch is just damned confusing to the press and public. Its like giving a baby a name while its in the womb and then changing after its born!

  9. I agree, Marshall, that was flippin’ cool! Which made made me doubly mad when that reporter was like “but my editor won’t like it because there’s nothing new.” Um, hello, the telescope team showed off its power and prowess and talked about its possibilities… that is exciting science news!

    Tod, a blazar is one of the many subtypes of active galactic nuclei, or the centers or galaxies where a supermassive black hole is accreting material. A blazar describes an object where we see lots of variability from that source, as well as other “observational signatures” that I don’t quite remember now. This might help for starters: http://en.wikipedia.org/wiki/Blazar

  10. ioresult

    If GLAST is male, then you say “né”, if it’s female, then it is “née”. You never, never say “neé”, that’s just wrong.

  11. firemancarl

    You never, never say “neé”, that’s just wrong.

    You mean you never say it to an old woman. Oh, what times are these ……

  12. firemancarl

    I canna wait to hear what NASA and the Fermis think about those other blasts. it ought to be good stuff!

  13. Wayne

    I’m such a geek. I heard about this today and immediately started checking for the inevitable blog post about it here. Thanks for not disappointing.

  14. JMA


    If you the “neé” in the sentence “NASA’s Gamma-ray large Area Space Telescope, neé GLAST, is now called Fermi!” is suppose to be the French word for being born (I’m not sure it is), the spelling is wrong. It should be “née” with the é in the second position (and also a telescope is a male word in French, so it should be “né” and and not “née” as for a female word).

    Well, it’s just a detail. Keep up the good work!


  15. Space Stations for Peace

    So at GLAST it has a proper name, Fermi! 😉

    Its been Fermi-enting for a while … now I think I’ll have a fermi-ented beverage to celebrate! 😉

  16. Space Stations for Peace

    Now GLAST has finally been given its new name (& personally I was thinking Gamow might have been better but anyway) …

    .. Isn’t it time that the International Space Station or ISS got itself a proper name? I suggest O’Neil-1, Babylon-1 or Goddard-Tsiolkovsky but I’d even take the original ‘Freedom’ above that dull acronymn.

    Hmm .. I wonder if Iran could be persuaded to join up &help build the Station if it gets its space program running well enough? Hey, it worked with Apollo-Soyuz & the Russians! 😉

  17. Torbjörn Larsson, OM

    Fermi also has half of the types of matter in the universe named after him as well; why not Villard?

    Quite right as far as ordinary matter goes, and it may even be worse, can’t it? The elementary fermions are what makes up matter, while elementary bosons are associated with radiation. (Though, I assume, not primary cosmic rays.)

    @ Tod:

    Spelling? Googling, the Wikipedia articleis on top:

    A blazar is a very compact and highly variable energy source associated with a supermassive black hole at the center of a host galaxy. Blazars are among the most violent phenomena in the universe and are an important topic in extragalactic astronomy.

    Blazars are members of a larger group of active galaxies, also termed active galactic nuclei (AGN). […]

    Not exactly a well referenced article though, so I dunno what is correct and what is wrong.

  18. Autumn

    “which used to be called the GBM for ‘GLAST Burst Detector'”

  19. StevoR

    Tod asked on August 26th, 2008 at 6:31 pm :
    “So, what’s a “blazar?” A blazing hot (radiation-wise) stellar object? I googled it and came up with nothing.”

    Please correct me if I’m wrong (& speaking off-top-of-head so may well be ..) but I think a Blazar is a bright Galaxy or galactic nucleus ie. a BL Lacertae object.

    Its a type of AGN (Active Galactic Nucleus) related to Quasars (brighter than Blazars?) and Seyfert galaxies.(Dimmer than blazars?)

    In a nutshell, (not that one would fit inside a
    nutshell but a-n-y-w-a-y ..)
    its a galaxy with an acytive, concentrated core which is variable, superluminous and involves a central supermassive black hole with associated jtes, accretion
    disk etc ..

    I think ..

    Or maybe its related to pulsars that are especially active &brilliant -magnetars? Hmmm… Not quite so sure myself now.

    Still hope that helps some…

  20. StevoR

    … & now I see thatwe n its comes to ‘Blazar’ I’ve been beaten to it earlier & more often!

    D’oh! Well at least I was right first time though! 😉

  21. travissimo

    So are the views from Fermi always super wide angle views or can it focus in a particular objects?

    I can understand the need to see the whole sky to detect bursts… space being kind of big and all. Is there ever a need for more detail of a region of space in regard to gamma rays?

  22. kebsis

    ”Fermi also has a Burst Detector (hmm, which used to be called the GBM for “GLAST Burst Detector”, so now it must be the FBD)”

    Why did they call it GBM? Or is that a typo?

  23. Looking forward to hearing more from Nasa on this one. Good stuff! keep up the great work!

  24. Andy

    Wow, I’m in awe at this picture. All the guys who worked hard to get the Fermi up and running must be feeling extremely satisfied at it and exited at all of the data about to come. Gee, I wish someday I can also do something that is both a first in the world and somehow useful to humankind.

  25. J_w23

    Hey Phil, guess it should be “GBD” instead of “GBM” which are both wrong since it is “FBD” but hey! Nice article!

  26. SLC

    This is an example of the kind of science that NASA can do. However, the manned space program, which takes up far too much of NASAs’ budget, prevents many such activities.

    1. The latest jeremiad from Bob Park on manned space activities.

    This week, according to today’s Science magazine, Senator Obama supported the Bush plan to return humans to the Moon. Replay Apollo? Not exactly; Obama wants a more international effort. You can see how well that worked with the ISS. Meanwhile in Cape Canaveral, McCain was backing the Bush plan to build a successor to the shuttle. Of course, he was in Florida, and that’s what politicians all say when they’re in Florida, but he did not favor returning to the Moon. ”

    2. Another jeremiad from Steven Weinberg from an interview with the web site Space Astronomy.

    “Professor Steven Weinberg: Yes, I think the ISS is just one example of NASA’s ridiculous overemphasis on manned spaceflight. It may originally have been intended to serve as a platform for going on to the Moon and Mars, but then the orbit was changed to make it accessible to Russian rockets. As a result it doesn’t even have that. There have been continual efforts to justify it in terms of science done on the ISS. It’s hard for any one scientist to judge work across a range of fields. I can say that in my own field, which is fundamental physics and astronomy, especially cosmology, it has produced nothing. I would have heard.

    In other fields I have heard talk about crystal growth and biological studies. There, I’m not competent to judge myself so I’ve asked people whose judgment I trust. Uniformly I hear nothing important has come out of it.”

    “Weinberg: There’s one episode in particular that really shows NASA’s contempt for science as compared for its concern for the mission of sending people into space. There’s a collaboration headed by Sam Ting, a Nobel Laureate at MIT, that has built an instrument call the Alpha Magnetic Spectrometer (AMS), whose purpose is to study primary cosmic rays of high energy above the Earth’s atmosphere. Cosmic rays above a certain energy can only be studied on the ground indirectly by studying the showers of charged particles that they produce. It’s been very hard; for instance, you lose all information about the direction they came from. You lose essentially all information about the composition of the cosmic ray. All you can really tell from the shower is just the energy that the particle carried.

    This collaboration wants to, for the first time, study high-energy cosmic rays directly above the Earth’s atmosphere. They built the spectrometer at a cost of over $1 billion. The money did not come from American sources; it came mostly from a European consortium. NASA had told them that it would bring it up to the ISS using the shuttle. It has now apparently reneged on that. It has said it does not want to devote a quarter of a shuttle load—which is what it would take, I’m told, to bring the AMS up to the ISS—and they just have turned their back on this commitment.”

    The entire interview is available at the following site.


    But of course, Profs. Park and Weinberg don’t know what they are talking about.

  27. Murgadroid

    nee, ne, or nee (hope the accents come through!).

    Bring me a shrubbery!

  28. TR

    All naming issues asside, I’m confused by the phrase “photons of light just like the ones we see (visible light photons), but with millions or even billions of times the energy.” If they are more billions of times more energetic, than they are not visible light photons.

    Or am I missing something?

  29. Wayne

    He means the ones we see are visible light photons, not the energetic ones. I think his point was that they are all photons, but you have to parse the parentheses correctly.

  30. Jeff

    Ah! Murgadriod beat me to it. That’s exactly what I thought of when the whole ne nee thing came up. http://lorien.sdsu.edu/~carroll/shrub.html

    “Oh not another shrubbery!!”

  31. Andy Beaton

    Given that all of the fermions in the universe are named after Fermi, he didn’t really need anything else named for him. But it’s still pretty cool.
    I’m wondering where 3C 273 is on that map? It’s the only quasar I have ever seen or most amateurs are likely to see, and I’m curious about whether it will show up here.

  32. SF Reader

    The Fermi Paradox is indeed science, in the sense that Isaac Asimov noticed that science starts with “Hey, that’s odd.”


  33. GF

    travissimo: The LAT instrument on Fermi sees about 20% of the sky at any
    one time. Within that field of view it is specified to have an angular resolution
    for point source localization of a bit better than one arc minute – roughly similar to the
    angular diameters of Venus or Jupiter as seen at their largest from Earth.
    The actual PSF is substantially larger than that, and a strong function of
    energy (because of the means by which gamma ray photons are detected):
    from 3.5 degrees at 0.1 GeV down to 0.1 degrees at 10 GeV.

  34. Michael I

    Personally, I think it should now be referred to as the FermI gamma-Ray Space Telescope.

    That way it goes from GLAST to FIRST


  35. Responses to some of the questions in the comments:

    1) Blazars are a subclass of active galaxy, in which the jets are pointed towards the Earth. Originally named after BL Lacertae, the term is now jargon for this subclass of active galaxies which are the most prolific gamma-ray emitters. The jets pointing at us emit LOTS of high-energy gamma rays, which are very variable and make blazar-watching very exciting.

    2) The correct name is the GLAST Burst Monitor (GBM.) There are no plans to change the name at the present time. Although, if they did, they would probably just redefine the “G” to be “gamma-ray.”

    3) NASA renames satellites after launch in general (big exception – James Webb Space Telescope) because it wants to be sure that they work well before naming them. This was true for Hubble, Chandra, Spitzer and WMAP as well. And yes, Fermilab is also named after Enrico Fermi. The Fermi Gamma-ray Space Telescope had major contributions from the US Department of Energy (which managed Fermilab) and from space and particle physics funding agencies in Italy. Both of these groups (as well as Fermi’s surviving grandchildren) were happy with the choice of the name.

    I gave a lecture today at the SETI Institute entitled “Exploring the Extreme Universe with GLAST (crossed out to say Fermi)” which will soon be available for viewing online through links at:
    if you would like to learn more. Or please visit our Education and Public Outreach website at: http://glast.sonoma.edu

  36. OMFSM. For some reason I typed “Burst Detector” (I remember thinking I was going to describe it as a detector, then changed my mind) instead of Monitor. i fixed that. Pretty funny; note that I got the acronym right! Wow.

    For those not in the know, lynnc is my old boss when I was at Sonoma State University, and she is the team leader for the E/PO for Fermi. So she knows her stuff! :)

  37. csrster

    Fermi also has the Fermi Surface (and associated Fermi Energy) in solid state physics, fermions/fermi-dirac statistics, the Fermi Mechanism for the acceleration of cosmic rays, and the Fermi Paradox. That’s before you get to boundary cases like “The Fermi Theory of Beta Decay”.

  38. Torbjörn Larsson, OM

    Fermi also has the Fermi Surface (and associated Fermi Energy) in solid state physics

    And while we are at it, such fermi surfaces explains most or all electron phenomena in normal metals as the electrons forms what I understand to be a fermi liquid. (You don’t always have to understand and distinguish between different fermi systems for working their basic properties, so it is a bit ephemeral knowledge for me.)

    I had to check up on a vague memory that there are a highly useful set of heuristic problems called “fermi problems” (there are) so I was reminded about the element fermium and that the physical realization of Fermi-Dirac statistics (underlying the exclusion principle) is called a “fermi hole”. But I had no idea he had a calculation method (“golden rule”) named after him as well.

    Busy man.

  39. StevoR

    Hubble used to be called something else???

    Whaaa …. !

    I sure don’t recall that.

  40. StevoR

    If you listen closely to the radio emissions pouring from the cores of Blazers like BL Lacerate you can hear them going …


    Congrats to all the folks at GLA .. Fermi !
    I’ll be raising my Gla — Fermi-ented beverage to them! 😉


    Babylon-1 for the new name of the ISS? I like the sound of that. 8)


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