Yerkes Astrophysics Academy for Young Scientists (YAAYS)Summer Institute 2007

Hubble data-mining project: The Ring Nebula M57Vivian Hoette and Max Mutchler

Our first YAAYS data-mining project: The Ring Nebula

• A student-teacher-scientist collaboration• Students learned how to display and manipulate real

astronomical data (FITS images), measure star positions and shifts (astrometry)

• Scientists used the shifts between images to combine them into one clean image

• Scientists learned which file formats and tools worked best: how to make the job easier for everbody

• “High level” data added to the Hubble archive • Poster describing this project• We are developing working relationships and learning

how to collaborate with each other• What worked? What didn’t work? What next !?!

Astronomers using the Hubble telescope have obtained the sharpest view yet of a glowing loop of gas called the Ring Nebula (M57 or NGC 6720), first cataloged more than 200 years ago by French astronomer Charles Messier. The pictures reveal that the "Ring" is actually a cylinder of gas seen almost end-on. Such elongated shapes are common among other planetary nebulae, because thick disks of gas and dust form a waist around a dying star. This "waist" slows down the expansion of material ejected by the doomed object. The easiest escape route for this cast-off material is above and below the star. This photo reveals dark, elongated clumps of material embedded in the gas at the edge of the nebula; the dying central star is floating in a blue haze of hot gas.

http://hubblesite.org/newscenter/archive/releases/1999/1999/01/

Ring Nebula 1999

For each filter, there are many images which need to be registered (aligned) before they can be combined

Students measured star positions in each image, to calculate the shifts between them.

Human eyes are better than computers at finding stars among the artifacts (mainly cosmic rays)…like finding needles in a haystack.

Blinking (comparing) the“before” and “after” images

• The “before” (pre-sum) image: cosmic rays, unregistered stars, camera artifacts

• The “after” (drizzle combined) image: registered, clean…what can you see now?

• Blink the next two slides back and forth a few times to see how we made the data better…

Ring Nebula F658N image “before”

Ring Nebula F658N image “after”

http://archive.stsci.edu/prepds/heritage/

Our improvedimages will be added tothe Hubble data archive as a“high level science product”,and be available forfurther research

F469N F502N F547M F658NHelium Oxygen wide, for stars Hydrogen

Making a color image by combining images from several filters

Our project was presented as a poster at a science workshop hosted by Yerkes Observatoryin April 2007

Workshop poster abstractThe newly-formed Yerkes Astrophysics Academy for Young Scientists (YAAYS) is an NSF-funded collaboration of students, teachers, and scientists at Yerkes Observatory. We have identified archival Hubble Space Telescope (HST) observations of the Ring Nebula (NGC 6720 or M57) for an initial excercise in the emerging field of astronomical data mining and curation. The multi-wavelength images of this object from the Wide Field Planetary Camera 2 (WFPC2) made it one of the best-studied planetary nebula, and it's sheer beauty as the first Hubble Heritage release in 1999 made it an instant Hubble icon.

In recognition of this dataset's importance to both the study of planetary nebulae and the legacy of Hubble Space Telescope, we chose to prepare and preserve it for posterity. We have collected all available archival WFPC2 data, including some obtained subsequent to 1999, and are converting it into a fully and expertly prepared scientific dataset, using calibrations, methods, and software not available in the 1990s. Our treatment of this dataset will make it more immediately science-ready (and education-ready) than the standard archival products. Further, our prepared dataset will be ingested into the Hubble archive as a High Level Science Product (HLSP), making it queryable by future Hubble and NVO-type data searches. We present our prepared dataset in honor of Bob O'Dell, who has been a central figure in making the Hubble mission a reality, and in making many groundbreaking observations of nebulae with it (including the Ring Nebula).