The University of Massachusetts Amherst

Feature Stories

First Light

World’s largest telescope reveals history of the universe
  • Large Millimeter Telescope Dish

“The killer app for our telescope is the study of galaxy evolution.” –Peter Schloerb, Astronomy

Drive the Mexican highway east from Mexico City toward Veracruz and you’ll see a strange goblet-like structure atop one of the continent’s highest peaks. “It’s a prominent and impressive landmark,” says UMass Amherst astronomist Peter Schloerb.

Climb to the top of the 15,000-foot Sierra Negra, with near-freezing temperatures even in summer, and you’ll be standing before the Large Millimeter Wave Telescope (LMT), an antenna 180 feet tall developed and built by a bi-national team led by UMass Amherst and its sister institute in Mexico: the Instituto Nacional de Astrofísica, Óptica, y Electrónica. If you visit, you are likely to bump into faculty and students from UMass Amherst’s astronomy department: scientists recorded the “first light” data on the telescope, from the galaxy Messier 82, and are pursuing a range scientific observations with the telescope.

“The killer app for our telescope is the study of galaxy evolution,” says Schloerb. “LMT receives light at millimeter wavelengths, and it is sensitive enough that we can survey the sky, find distant galaxies, and pursue them with follow-up studies.” The telescope fills a valuable and distinctive place in the international pursuit to understand galaxy evolution. Its large size, sensitive instruments, and ability to operate at short millimeter wavelengths give it advantages over other well-known telescopes, especially for surveys of the millimeter-wave sky. “We can do the work of more powerful instruments, but faster. So our bread and butter is making surveys of the sky,” says Schloerb.

UMass Amherst has been able to play an important role in this project, Schloerb explains, because over the past 30 years, the campus has assembled a world-class team of instrument builders. Two key instruments on the LMT are the Redshift Search Receiver and the AzTEC. The Redshift Search Receiver, which measures the distance to galaxies at great distances, was designed and built by UMass astronomers Neal Erickson and Gopal Narayanan. UMass astronomist Grant Wilson did the same for AzTEC, a 1.1 mm camera that gives the telescope its ability to make images and search the sky for new distant galaxies.

“These are not instruments you can simply order,” Schloerb says. “If you want to stay as state-of-the-art as our lab, you need to build them to your specifications yourself.” In fact, the Millimeter Wave Instrument Lab on campus builds instruments for others that don’t have the technology or facilities such as a set of receivers for a Korean telescope. “We are always building something,” he says.

After demonstrating its basic capabilities with the observations of Messier 82 and a few more distant targets, researchers began a phase of scientific work designed to show that the LMT is making the kind of forefront observations that it was designed and built to do.

Scientists are using the LMT to seek new dusty galaxies at great distances, “and if you can measure the redshift of these objects,” says Schloerb, “which we can do using our world-class Redshift Search Receiver, then you can determine their distance and their intrinsic properties.” Moreover, because of the fixed speed of light, observations at greater and greater distances correspond to observations of galaxies at earlier and earlier times in their history. In this way, the whole evolution of galaxies can be observed with the telescope. So the work of a few UMass Amherst astronomers building instruments on campus and a few more atop a frigid mountain peak, and in collaboration with colleagues in Mexico, allows us to see farther into the sky and farther into the past.

David Bartone '12G