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.

How To Find NEOs

SDSS imaging data consist of 6 strips called “camcols”. The above image is a small portion of a “run” that extendsfor 800 fields.

Camcols 1 2 3 4 5 6

5Fields

Near Earth Objectsshow up as streaksin 3 colors

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

Job Statistics

Run-RerunAvg: 150 Fields

camcol 1 camcol 2 camcol3 camcol4 camcol5 camcol6

6 Tar ballsAvg: 1.5*6=9 GB

Neo-$run-$camcol-Input.tar

Neo-Executable

6 Neo Par FilesAvg: 2*6=12 K

neo-00$run-$camcol-$rerun.par

Total Jobs Total Jobs 180180

Total Input Data Total Input Data 9*180=1620 GB9*180=1620 GB

Total Output Total Output DataData12*180=2160 K12*180=2160 K

OSG- SiteOSG- Site

OSG-SiteOSG-SiteOSG-SiteOSG-Site OSG-SiteOSG-Site

SDSS Cluster

TAM Cluster

GFS Disk Local Disk

RLS Server on TAM

VDL Generation

VDL2XML

Abstract DAX Creation

Concrete DAG Creation

Condor Submit DAG

Compute NodeLocal Disk

Register Input Files

Query RLS to Create Condor Submit File

NEO WORKFLOW

Copy Input to Local Disk

Copy Output Back

Register Output FilesTransfer Output Back to TAM

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