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Cosmic Microwave Background Data Analysis At NERSC

Cosmic Microwave Background Data Analysis At NERSC. Julian Borrill with Christopher Cantalupo Theodore Kisner. What Is The CMB ?. Cosmic - filling all of space. Microwave - redshifted by the expansion of the Universe from 3000K to 3K.

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Cosmic Microwave Background Data Analysis At NERSC

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  1. Cosmic Microwave Background Data Analysis At NERSC Julian Borrill with Christopher Cantalupo Theodore Kisner

  2. What Is The CMB ? Cosmic - filling all of space. Microwave - redshifted by the expansion of the Universe from 3000K to 3K. Background - primordial photons coming from “behind” all astrophysical sources. A snapshot of the Universe when it first became neutral 400,000 years after the Big Bang.

  3. Why Do We Care About The CMB ? The CMB is a unique probe of the very early Universe. Its tiny (1:105-8) fluctuations carry information about - the fundamental parameters of cosmology - ultra-high energy physics beyond the Standard Model

  4. What Does The CMB Look Like ?

  5. CMB Work At NERSC • Started in 1997: • 2 separate allocations for Maxima & Boomerang • together 5 users & 30,000 CPU-hours • Developed into premier world center for CMB analysis: • single allocation shared by O(10) experiments • O(100) users & O(1,000,000) MPP-hrs/year • Now includes "Big Science" satellite mission • split into two allocations • mp107 - 13 sub-orbital experiments 40 users & 500,000 MPP-hrs • planck: Planck satellite 60 users & 2,000,000 MPP-hrs*

  6. The Planck Satellite • The primary driver for current NERSC CMB work. • A joint ESA/NASA mission due to launch in the fall of 2008. • An 18+ month all-sky survey at 9 microwave frequencies from 30 to 857 GHz. • O(1012) observations, O(108) sky pixels, O(104) spectral multipoles.

  7. Data Management • Dominated by time-ordered data • O(1-10) TB, O(10,000- 100,000) files • Each data set must be analyzed as a whole. • Each data analysis needs O(100x) storage. • Each data set may have its own format/distribution. • Each data set must be selectively shared. • Requires • Pre-fetching & active disk quota management • Efficient & abstracted run-time reading • Project account

  8. Task Management • Any member of a team must be able to • Access all the data • Access all the general & project-specific codes • Generate and execute standard analyses • Share the results with the team • Some members of a team must be able to • Control the overall team work-load/-distribution • Manage software versioning and access • Requires • Project account with individual user certification • Limited capability for most; full capability for some. • Synchronized data-for-task management

  9. A Framework for CMB Analysis At NERSC

  10. Critical Components & Issues • NERSC Global Filesystem • access from Franklin • Storage Resource Manager • optimal transfer protocols • Project quotas • separation from UNIX groups • Project accounts • appropriate queue limits • User accounts • maintain (unique) accessibility • Modules • work just fine

  11. Conclusions • NERSC has developed into the world's leading center for HPC for CMB data analysis • Recognized as such by the recent NASA/NSF/DOE Weiss report on the future of CMB research. • This reflects the NERSC resources' • capacity and capability, • accessibility, • long-range development plan. • Long may it continue !

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