Transcript YAAYS_M57_closure

Yerkes Astrophysics Academy for Young Scientists (YAAYS)
Summer Institute 2007
Hubble data-mining project: The Ring Nebula M57
Vivian 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 !?!
Ring
Nebula
1999
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/
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
improved
images will
be added to
the Hubble
data archive
as a
“high level
science
product”,
and be
available for
further
research
F469N
Helium
F502N
Oxygen
F547M
wide, for stars
Making a color image by
combining images from several filters
F658N
Hydrogen
Our project
was
presented
as a poster
at a science
workshop
hosted by
Yerkes
Observatory
in April 2007
Workshop poster abstract
The 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).