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SOURCE: Al Harper/University of Chicago

The HAWC (High-resolution Airborne Waveband Camera) in the lab at the Yerkes Observatory. The infrared camera is being tested and fine tuned in  coming months to be sent to the Jet Propulsion Laboratory in California, where it will be prepared for use on NASA's SOFIA. The camera and associated technology will offer a new view of the stars.  

HAWC camera to patrol skies on NASA’s SOFIA

by Fouad Egbaria
Feb 07, 2013


SOURCE: Al Harper/University of Chicago

A model of SOFIA (Stratospheric Observatory for Infrared Astronomy), purchased by NASA in 1997 from United Airlines and repurposed as a flying astronomical observatory.

In the near future, a new sort of bird will patrol the skies.

Researchers at the University of Chicago, Northwestern University and, eventually, at NASA’s Jet Propulsion Laboratory, are building a new camera, called HAWC, for use on SOFIA, NASA's stratospheric observatory craft. Using the infrared spectrum, the camera would allow scientists to observe the universe with otherwise undetectable views of distant stars.

“We’re very anxious to get our chance to fly our instrument and to continue the kinds of observations that we began with the Lear Jet and the Kuiper [Airborne] Observatory,” said Al Harper, a professor in the astronomy and astrophysics department at the U of C. Harper began his career as a graduate student flying a 12-inch telescope on a Lear Jet.

HAWC stands for “High-resolution Airborne Waveband Camera.”

The camera is being built in the university’s Yerkes Observatory in Williams Bay, Wis., but will be sent off to JPL in California within the next six months, where it will undergo, an “upgrade,” according to John Vaillancourt, an instrument scientist with SOFIA since 2009. He is interfacing between SOFIA and the HAWC team until the camera moves to JPL. After that, it’s his bird and he will be in charge of running it and making sure everything on it works appropriately.

HAWC will be ready for use on SOFIA in approximately two years, according to Harper.

Giles Novak, a professor in the Department of Astronomy and Astrophysics at Northwestern University, and NU colleague Nicholas Chapman, are the primary scientists collaborating on HAWC’s new software, which will give HAWC the ability to produce polarization images. These images will allow scientists to, in addition to discerning the infrared outlines of stars and dust, but their alignments and orientations as well.

According to Novak, the wider purpose of HAWC’s deployment on SOFIA is to investigate why most stars possess a mass of 10^30 kg. If stars weighed more, they’d theoretically have much shorter lives. If they weighed less, it could prevent the formation of water on planets orbiting these smaller stars, Novak said. These theories would have implications on the evolution of life, he added.

“There are some theories that use magnetic fields to regulate the star formation process,” Novak said. “In other words, the magnetic field of the galaxy can influence the star formation process. Those are the theories we want to test with HAWC.” By testing these theories, scientists can get at the cosmological basis for the minimal variance in star mass.

“We’re currently putting new detectors and a polarimeter into the instrument that we’ve already built and run in the laboratory here,” Harper said. “We expect that to start flying on [SOFIA] in about two years.”

“It’s particularly important to have a number of different techniques to study the same object,” Harper said. Harper specializes in the far infrared wavelength, which is between microwaves and visible light in wavelength on the electromagnetic spectrum. Studying the cosmos in the infrared spectrum allows scientists to see things that would not be seen in the visible spectrum of light.

According to the SOFIA website, HAWC is one of nine “first light instruments” in production for use on SOFIA, of which include cameras (like HAWC),spectrometers and photometers.

The use of infrared astronomical equipment is not new. NASA has been using it since the 1960s, with the Lear Jet and Convair CV-990. However, HAWC offers some new features with its detectors and polarization technology.

“HAWC is conceptually a simple instrument,” Vaillancourt said. “This sort of work has been done before, but never with as large a focal plane as HAWC will have and never from as large of a telescope,” he added. As such, HAWC will have improved spatial resolution, meaning it will be able to see a larger piece of the sky with smaller pixels in the image.

One use for HAWC is the monitoring of star-forming regions in the Milky Way.

“Because you can’t see the stars themselves, we can infer by the temperature of the dust and how much dust there is, to say something about the star [and] the environment that stars form in,” Vaillancourt said.

SOFIA, with respect to HAWC or otherwise, does a significant amount of work in probing and attempting to understand the universe at large.

“The chemistry of interstellar medium, which can lead to the chemistry of life, and all those sorts of things, are really important things to understand. And that is what SOFIA is going after: from how stars form to the atoms and molecules themselves,” Vaillancourt said.