New Mexico State University News Feature

by Minerva Baumann

2015 February 2

Scientists in January announced a final data release for the third phase of the Sloan Digital Sky Survey that includes information to allow researchers to construct a three-dimensional chemical map of the Milky Way galaxy. While this concludes a chapter in the survey, another one began last summer.

For the last six years, New Mexico State University astronomers, along with collaborators from member institutions around the world, have been using the 2.5-meter telescope at the Apache Point Observatory to complete a suite of experiments that includes studies of Milky Way stars to unlock the history of our galaxy, a study of cosmic structure traced by galaxies and intergalactic hydrogen to characterize the expansion of the universe, and a study of 3,000 nearby stars to search for the presence of unseen planets around them.

“The Sloan Digital Sky Survey overall is among the largest and most-cited ground-based astronomical surveys in the world,” said Reinirus Walterbos, NMSU distinguished professor of astronomy in the College of Arts and Sciences and the chair of the Astrophysical Research Consortium Board of Governors, which has oversight for Apache Point Observatory and its four telescopes.

The observatory’s telescopes include the 3.5-meter Astrophysical Research Consortium telescope, the 2.5-meter telescope of the Sloan Digital Sky Survey, the 1.0-meter NMSU telescope and a 0.5-meter telescope. It is located in the Sacramento Mountains, about 20 miles south of Cloudcroft, and is within the Lincoln National Forest.

SDSS began mapping the cosmos in 1998. Each phase of the project has used the dedicated 2.5-meter Sloan Foundation Telescope, equipped with a succession of powerful instruments, for a distinct set of astronomical surveys. SDSS-III started observations in July 2008 and completed its six-year, $45 million program in June 2014 with its final data released last month.

SDSS III "Data Release 12" (DR12) contains 100 terabytes of data with measurements of the properties of nearly half a billion stars and galaxies. The final data release from this phase of the project makes it one of the largest and richest databases in the history of astronomy.

“The SDSS projects have generated over 6,000 papers worldwide with over 263,000 citations,” Walterbos said. “There are certainly more than 100 papers that NMSU students, staff and faculty have been involved with over the course of the survey.”

With the Apache Point Observatory Galactic Evolution Experiment (APOGEE), researchers from around the world have catalogued data on more than 150,000 stars -- mostly within the Milky Way -- to determine what the stars are made of and to precisely measure how fast the stars are moving toward or away from Earth.

"This database expands the number of stars with detailed chemical abundance measurements by an order of magnitude compared with previous studies,” said Jon Holtzman, NMSU astronomy professor and department head. “Working in the infrared portion of the spectrum, the APOGEE survey observes stars that are buried in the dust that lies in the plane of the Milky Way." The data gathered is available online for everyone from academics and amateur astronomers to schoolchildren. SDSS has gained popularity through public access via sites such as Google Sky and Galaxy Zoo. Data Release 12 is available at http://www.sdss.org/dr12/.

NMSU has already begun Phase IV of SDSS, the next six-year mission, which runs through 2020. It will include data from the Sloan telescope at Apache Point Observatory and an additional telescope in Chile, adding to the database with a better view of the southern sky.

“Phase IV of the survey has added a new component called MaNGA, a mapping survey of nearby galaxies where we use the existing spectrograph that can take 1,000 spectra in a new way,” Walterbos said. “We can now also group these 1,000 fibers into a smaller set of bundles to make a larger view of field for nearby galaxies so we can get complete spectroscopic images of these galaxies. MaNGA will do a survey of 10,000 galaxies."

In addition to providing astronomical research data, through SDSS and the Astrophysical Research Consortium, Apache Point Observatory also has a significant economic impact on the region to the tune of about $3.5 million a year.

“We have 29 fulltime staff ranging from those with a high school education to currently about seven Ph.D.s on staff,” said Mark Klaene, operations manager of the site. “We’re one of the larger employers in Otero County. In addition, we bring that money into the state from outside the state unlike many other organizations in the region. Nearly all of that money goes back into the community via things like salaries, utilities and housing.”

Scientists are not their only visitors. APO and the neighboring solar observatory attract 10,000 tourists to the area through the Sunspot Astronomy Visitor Center and Museum.

Klaene points to the open houses APO has hosted periodically since he started managing the site as a big draw for the public.

“We set aside half a night and open the telescope,” Klaene said. “There’s just some romance to seeing it with your own eyes so we put an eyepiece on the telescope and point it to the moons of Jupiter, some of planetary nebula, the galaxies and let people actually see through their own eyes. About 90 people is the most we can handle. Every time we’ve done it we always get great reviews, we’ve always been booked solid and normally have to turn a few people away.”

Staff members who work at the observatory also conduct educational outreach programs for area schools and communities. They take scaled down models of telescopes, mirrors, plugging plates and even small star wheels made from colored construction paper showing maps of the stars so students can learn more about astronomy. They hope this kind of engagement will attract budding scholars to the STEM fields.

“We let the children know what we do,” said Diana Holder, a fiber technician who works with the 2.5-meter telescope. “When people come to the open houses or come to the public outreaches, they’re excited that we’re in the community. This just encourages them, it shows them the fun aspects of science.”

Group tours of the facility should be booked in advance and are limited to certain times of year. For more information on visiting the facility, contact Beth Mitchell at bmitchell@apo.nmsu.edu.

Copyright © 2015, Brian Webb. All rights reserved.