data mining and visualization in radio astronomybkent/talks/bkent_vis2010.pdf · visualization...
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Data mining and Visualization in Radio Astronomy
Brian R. KentNational Radio
Astronomy Observatory
http://www.cv.nrao.edu/~bkent/
Visualize 2010
STScI and NASA
STScI and NASA
Katie Chenoweth et al.
Springel et al.
Abazajian et al 2009 and the SDSS Survey
New Astronomy Across the Spectrum
More pixels Faster computing More data
Sensitive “cameras” Larger surveys Higher resolution
Jorden 2008 (Astrophysics Detector Workshops)
Visualization challenges
• Sheer file and database size!• Variable reduction and Analysis efficiency• Viewing modes for 3D and 4D data• Cross correlation of cataloged data• Efficient database mining• Mosaicking and projection algorithms
Center for Cosmo Physics
Use of Montage for large mosaicking…
Montage allows:
Online combination of imaging surveys
Limited online combination of user images
Unlimited combination programmatic interface
Berriman et al. 2006
The Arecibo Radio Telescope andArecibo L-band Feed Array
The new surveys of Radio Astronomy
• Meridian transit survey strategy.• 7000 square degrees of high galactic
latitude sky with the 7-element Arecibo L-band Feed Array.
• Sensitivity down to 2 x 107 Msun at DVirgo= 16.7 Mpc
• Primary sky targets include Virgo, Leo, and void regions.
• Objectives include public release catalogs and statistics, HI mass function determinations for various environments, and cross-correlation with other wavelength regimes.
Generating ~50 TB of processed datacubesKent et al. 2008, 2009
1225-1525 MHz
The new surveys of Radio Astronomy
• Meridian transit survey strategy.• 7000 square degrees of high galactic
latitude sky with the 7-element Arecibo L-band Feed Array.
• Sensitivity down to 2 x 107 Msun at DVirgo= 16.7 Mpc
• Primary sky targets include Virgo, Leo, and void regions.
• Objectives include public release catalogs and statistics, HI mass function determinations for various environments, and cross-correlation with other wavelength regimes.
Generating ~50 TB of processed datacubesKent et al. 2008, 2009
1225-1525 MHz
Right Ascension=12 hr
Arecibo Large Sky Survey
(Equatorial Coordinates)
FITS to IDL
Bandpass Calibration
Interferenceflagging
2D signal extraction
Data cube gridding
Baseline Flatfield
Data Cube Visualization
3D signal extraction
Flux Measurement
ALFALFA Data Processing Pipeline
Export
Frequency (100 MHz wide)
Tim
e (s
econ
ds)
Distant GalaxyGPSLong range radar
Milky Way
Each Data Element: • 4096 Freq. Channels• 2 polarizations• 7 receivers• 1 second sampling• 600 records• 20736 pixels
GRIDview: Spectroscopy & Visualization analysis tool
• Flexibility for – Native IDL structures– FITS data with astronomy headers
• Suite of OOPs include:– Visualization and imaging procedures– Spectral line measurement and fitting tools– Catalog and database programs
• Extensibility:– Import other user catalogs (ASCII, FITS, XML)– Add other imaging databases (WSDL, XML)
Map display window
Spectral normalization display window
Grid header and coordinate information
Cube manipulation controls
“Slide” to a lower Doppler velocity range
Galaxies are detected…
Nice spiral UGC 8475
Overlay catalogs from various sources…
Examine continuum maps…
Fetch radio images…
“Slide” to a lower Doppler velocity range
Galaxies are detected…
…including this nice spiral!
Back to Spectral mode…
Grab spectrum from a single pixel in the data cube.
Fetch images from online databases
Fetch data from NASA Extragalactic database
Obtain a larger image and position
Query archival databases
Summary• The GRIDview suite is a fast, OOP suite written in IDL
for 3D spectroscopic visualization.• The software is used on several large astrophysical
projects across 40 professional and academic institutions.
• Information: http://www.cv.nrao.edu/~bkent/computing