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Mexico's Large Millimeter Telescope Opens for Business

Up in the air. The Large Millimeter Telescope was constructed on the summit of one of Mexico's tallest volcanoes.

Copyright Large Millimeter Telescope, Jorge Reyes

Perched on the summit of a dormant volcano in the Mexican state of Puebla, the Large Millimeter Telescope (LMT) watches how stars, galaxies, and planets form. The result of a binational collaboration between the University of Massachusetts, Amherst, and Mexico's National Institute of Astrophysics, Optics, and Electronics (INAOE), the LMT saw first light in 2011 and is about to begin its first scientific observation season. ScienceInsider chatted with LMT Director David Hughes about millimeter-wavelength telescopes, Mexico's growing astronomy community, and his plans for the LMT's future. This interview has been edited for brevity and clarity.

Q: What makes the LMT unique?

D.H.: If we talk only of single dish, steerable, millimeter-wavelength telescopes, then the LMT is the world's largest. Since its very conception, it's been designed to operate optimally at high millimeter frequencies or short millimeter wavelengths. And it's been constructed on the summit of the Sierra Negra, a 4600-meter-high volcano in central Mexico. The combination of the physical size, the optimal design for millimeter wavelengths, and the high altitude makes the LMT unique.

Q: What are the advantages of millimeter-wavelength astronomy?

D.H.: At millimeter wavelengths, we are sensitive to the coldest objects in the universe. And those are typically found in the most dense and obscured regions of the universe, and in particular the most dense and obscured regions of star formation. We're actually seeing the initial stages of structure formation in the universe, all the way back to the Big Bang. More locally, in our galaxy, we're able to see the formation of planets. So it's an opportunity to really study how the universe has evolved from shortly after the big bang to the observable universe we see around us today.

Q: How did you get involved with the LMT?

D.H.: I'm British, so the first I heard of the LMT was in 1997 at a conference in the Canary Islands. I was presenting a paper on the future of observational cosmology at sub-millimeter and millimeter wavelengths and talking about the need to develop new and larger facilities to make significant advances in some of the fundamental questions related to the formation and evolution of structure. At the coffee break, a gentleman comes up to me and says, "I am Alfonso Serrano. I am building a telescope just for you!" I had never met him before, but he gives me his card and says he's the principal investigator in Mexico for a telescope called the Large Millimeter Telescope.

And then about 8 months later, I see that the LMT is advertising two positions for astronomers. I apply and I'm invited out to Mexico to attend a meeting, see the institute [INAOE], and meet researchers here. The trip happened to coincide with the publication of a Nature paper that I was the first author on where we were talking about the discovery of a new population of sub-millimeter galaxies. So there's some interest in interviewing me and whilst I'm here I'm made an offer. Eventually I accept, and I arrived in Mexico in January 1999, a bit more than 14 years ago.

Q: What has your experience been like doing astronomy in Mexico?

D.H.: Amazing! There wasn't a millimeter-wavelength community in Mexico when I arrived. Historically, the Mexican astronomy community has been focused around optical and infrared telescopes. So the challenge was to build a group at the institute and train a first generation of M.Sc. and Ph.D. students, and also to use my existing connections and collaborations to help me develop a millimeter-wavelength instrumentation laboratory.

I'm now benefiting from that because a number of my students that have gone out and worked in other world class groups have had the opportunity to return to the institute as more senior researchers and start to train their own students. What I now have is a core group of experienced faculty members and postdocs who are in a position to train other members of the Mexican community and also exploit and push the scientific development of the telescope. What's very rewarding for me now is that the second generation, the students of my students, are now the users of the LMT.

Seventy percent of the funding for the LMT has come from Mexico, and this is a telescope built in Mexico. So it's very important to me that I've been able to help create the first generations of Mexican astronomers that will use the LMT—hopefully for their entire careers.

Q: I heard a rumor that some of the panels were stolen off the telescope. Is that true?

D.H.: No. There were some fantastic images that were distributed in the Mexican press that showed the telescope without any panels, and this was simply a photo that was taken before any panels were installed. But the idea was somehow panels had been stolen from the telescope. So that's not true. There were panels that were removed from the institute, but that was a separate issue and those have been returned.

Q: The LMT is about to start early science observations. What has the response been like?

D.H.: There were 34 proposals for only about a 10-week observing period, which was fabulous. There is a requirement at least in these first stages in the operation that the proposals are written by the LMT partners, but many of the proposals have international collaborators. I'm very encouraged by the response.

Normally when you have a mature, completed facility, you'd make a call for about 6 months of proposals. In our case, we will be doing a lot of engineering work over the summer to install an active surface system, which will allow us to come back in the autumn with a telescope that has much higher performance. And we'll also take advantage of the full dry season, which is essentially October through May.

Q: What are your plans for the future of the LMT?

D.H.: The first thing is to finish the surface. Physically, it's a 50-meter-diameter telescope, but at the moment, we're operating with just an interior part that is 32 meters in diameter. We're working to try to complete the telescope surface by the end of 2014. But the telescope without instruments isn't anything, and instruments without a good telescope mean nothing either. So in parallel, we have begun the development of next generation instruments. Over the course of the next 5 years, I'm expecting that we will see the completed telescope and optimized surface as well as the second generation of instruments commissioned and operational—greatly enhancing the scientific capabilities of the LMT.

Telescopes typically have lifetimes of 30, perhaps 40, years. Once the telescope is complete in terms of its full size, then you constantly try to optimize the mechanical system and the actual telescope surface to make the telescope as efficient as possible. And in parallel, you constantly try to take advantage of new technologies to build more capable and sensitive instruments. That's a continuing process for the coming decades.