August 10, 2004August 10, 2004

Apache Point Observatory, NM

FINDING SUPERNOVAE IN A FINDING SUPERNOVAE IN A SLICE OF PISLICE OF PIDennis J. LamentiDennis J. Lamenti

San Francisco State UniversitySan Francisco State University

OutlineSloan Digital Sky Survey

Sloan Telescope

Supernova Type Ia

Data Processing Challenges

PlotFits.java

Results

Conclusion

Future

Sloan Digital Sky SurveySDSS goal is to conduct fundamental research in cosmology

The approach is to map a quarter of the sky in 5 filters

Obtain spectra of 1 million galaxies and 100,000 quasars

Determine positions and absolute magnitudes of 100 million astronomical objects

Project life: 2000 - 2005

SDSS Extension

Proposal to extend SDSS 2005 – 2007

Continued opportunity for further science

Initiate supernovae search program

Sloan Telescope

2.5 m reflecting telescope

Wide Field Imaging camera

Color information in 5 different filters

Camera built with 30 CCD's

Each CCD has 4 million elements (2048 x 2048 elements)

Utilized 'drift scan' operation

Sloan Telescope

Sketch of array of CCD in camera

Sloan 2.5 m telescope, www.sdss.orgRay Trace of incoming light

Picture of actual CCD array in telescope, www.sdss.org

Supernova Type IaSupernovae are gigantic thermonuclear explosions

Light emitted can outshine whole galaxy

Uniform peak brightness

Distance indicators, standard candles

Studying SN Ia led to discovery of acceleratedexpansion of universe

Acceleration implies Dark Energy

Learn more about properties of Dark Energy

Z = V = C*ZV=H*dH*d = C*Z

Supernova Type Ia

Artist Rendition of Accreting White Dwarf

QuickTime™ and aYUV420 codec decompressor

are needed to see this picture.

Created by Supernova Cosmology Project

SDSS Supernova SearchSearch goal is to obtain 200 supernovae with light curves

Upon discovery, follow up for spectroscopy

Redshift coverage .05 < z < 0.3

Saul Perlmuter, et al.

Data ProcessingTemplate image of sky has been created from past runs

Scans same region of the sky every two nights, search image

Search image subtracted from template creates subtracted image

Notice appearance of new objects

24 Gigabytes per night

Data processing includes:Reduces noise to signalCorrects for atmospheric conditionsDetermines precise locations of stars and galaxiesMatches frames from search and template imagesSubtracts search and template framesDetermines possible SNe candidatesStores candidate information in mySQL database

PlotFits.java PlotFits.java graphical output will assist in determining SN candidates

Code was written to zoom into region of candidate and plot2-dimensional histogram

Utilizes JAIDA, which is JAVA implementation of the Abstract Interfaces for Data Analysis for plotting histograms

Calls the Java Fits utilities to read and write FITS files

Uses mySQL Connector/J driver for JAVA to interact with mySQL

PlotFits.java: Flowchart

APO Photo

mySQL

FITS filesin cluster

FrameSubtraction

PlotFits

PlotFits.java: Outputg i r

Results

First possible SN candidate found using FRAME SUBTRACTION

Hupert Lampeitl, FNAL

Results: PlotFits.java g r

Results: False Positives

Results: False Positives:2

Top to right, then bottom; subtracted, search and template image, respectively

Conclusion PlotFits can be used to determine candidates

Can also determine false positives

Present information to scanner in an automatic way

With quicker determination of candidates, faster follow up.

FutureTest run Fall 2004

Develop Graphical User Interface

Enhance plotting display with additional graphs

Experience will develop greater proficiency in identifying objects

Acknowledgements Fritz DeJongh, FNAL

Sloan Digital Sky Survey, Supernova Group, FNAL

Experiment Astrophysics Group, FNAL

Summer Internships in Science and Technology (SIST), FNAL

Elliot McCrory, Chairman SIST, FNAL

Diane Engram, Head of EOO, FNAL

James Davenport, SIST