august 10, 2004 apache point observatory, nm finding supernovae in a slice of pi dennis j. lamenti...
TRANSCRIPT
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