2. Near Earth Objects Near-Earth Objects (NEOs) are comets and asteroids that have been nudged by the gravitational attraction of nearby planets into orbits that allow them to enter the Earth's neighborhood. Composed mostly of water ice with embedded dust particles, comets originally formed in the cold outer planetary system while most of the rocky asteroids formed in the warmer inner solar system between the orbits of Mars and Jupiter. The scientific interest in comets and asteroids is due largely to their status as the relatively unchanged remnant debris from the solar system formation process some 4.6 billion years ago. 37 Near Earth Object candidates are identified in Sloan Digital Sky Survey imaging data. The objects have apparent magnitudes r=19 – 21 and proper motions of 1.3 to 18 degrees per day. The earth collision rate for this population (size greater than 20 m) is estimated to be one per century.

3. How To Find NEOs SDSS imaging data consist of 6 strips called “camcols”. The above image is a small portion of a “run” that extends for 800 fields. Camcols 1 2 3 4 5 6 5 Fields Near Earth Objects show up as streaks in 3 colors

4. Why OSG ? Experience tells us that Grid is more suitable for CPU Intensive Jobs. Neo Jobs are Data Intensive but also need fair amount of CPU time. Also, to achieve PARALLELISM …  More Jobs…finish sooner  Running locally would limit the number of jobs run simultaneously  On OSG, can run several run-rerun and camcols within a run-rerun in parallel Current Workflow also will facilitate further analysis

5. Job Statistics Run-Rerun Avg: 150 Fields camcol 1camcol 2camcol3 camcol4camcol5 camcol6 6 Tar balls Avg: 1.5*6=9 GB Neo-$run-$camcol-Input.tar Neo-Executable 6 Neo Par Files Avg: 2*6=12 K neo-00$run-$camcol-$rerun.par Total Jobs 180 Total Input Data 9*180=1620 GB Total Output Data12*180=2160 K

6. OSG- Site SDSS Cluster TAM Cluster GFS DiskLocal Disk RLS Server on TAM VDL Generation VDL2XML Abstract DAX Creation Concrete DAG Creation Condor Submit DAG Compute Node Local Disk Register Input Files Query RLS to Create Condor Submit File NEO WORKFLOW Copy Input to Local Disk Copy Output Back Register Output Files Transfer Output Back to TAM

7. Future EAG Grid Projects… In the coming year 2005-2006 Experimental Astrophysics Group ( EAG ) has 4 projects planned for the Open Science Grid  The simulation effort for the DES  Genetic algorithm fitting of SDSS quasar spectra  Search for near Earth asteroids in the SDSS imaging data  The coaddition of the SDSS southern stripe.  Thankyou