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Project TanagraTiming Analysis of Grating DataVinay Kashyap (SAO)Jennifer Posson-Brown, Jeremy Drake, Kathy Reeves, Steve Saar (SAO), Raymond Wong, Thomas Lee (UC Davis), Alanna Connors (Eureka), Jeff Scargle (NASA/Ames)
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Darmok
2Tuesday, December 13, 2011
Darmok and Jalad at Tanagra
3Tuesday, December 13, 2011
Lightcurves and spectra with Chandra
A different kind of datasetgrating observations made with Chandra X-ray Telescope
A bountiful spectro-temporal mine to dig
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A different kind of dataset
peer-selected “interesting” bright X-ray sources
long-duration observations
photons with wavelength and arrival time attributes
excellent spectral and timing resolution
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HETGS+ACIS-S Grating Spectra
180 Chapter 8. HETG: Chandra High Energy Transmission Grating
Raw Detector Image, ACIS Energy Color-coded
MEG Minus-First Order Spectral Images19 A 15 A
9.25 A 6.7 A
12.2 A
17 A
HEG
MEG
MEG-minus spectrum
S0 S1 S2 S3 S4 S5
Aspect corrected Sky Image, Zeroth and First Orders Selected
Figure 8.1: HETGS observation of Capella, Obsid 1318. The top panel shows an imageof detected events on the ACIS-S detector with the image color indicating the ACIS-determined X-ray energy. The bright zeroth-order image is visible on CCD S3 and includesa trailed image (the vertical frame-transfer streak). Diffracted photons are visible forminga shallow “X” pattern; the HEG and MEG spectra are indicated. The images are broaddue to dither of the spacecraft. The middle panel shows an image after the data have beenaspect corrected and selections applied to include only valid zeroth and first-order events;note that the Y axis has been flipped from the normal Sky view to match the detectorcoordinates view in the top panel. Finally, the lower panel shows an expanded view of theMEG minus-first-order spectrum with emission lines clearly visible.
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HETGS+ACIS-S Grating Spectra
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HETGS+ACIS-S lightcurves
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HETGS+ACIS-S lightcurves
9Tuesday, December 13, 2011
Sounds grand.Why hasn’t anyone looked at all this yet?
Barriers to entry
few to none general algorithms to deal with (t,λ)
no “statistically complete” samples
all the easy bits already done by PI
do you really have to sit and stare at each observation?
I am on the lookout for algorithms
10Tuesday, December 13, 2011
My Motivation
solar and stellar flare energies are distributed as power-laws, dN/dE ~ E-α, with α<2 for Sun, and α>2 for low-mass stars.
probably due to self-organized criticality in magnetic field structures
Questions: is α a function of spectral type? is a single power-law a consistently good description? is there a dependence of α on luminosity or on plasma temperature? where is the lower cut-off to the distribution?
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Your Motivation
A different kind of data mining
Digging deep into a single source
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Illustrative example: AU Mic
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Illustrative example: AU MicJeff Scargle’s adaptive histogram
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Illustrative example: Procyon
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Illustrative example: Procyon
α ! 1.7
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Illustrative example: FK Com
line centroid shifts with time
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Illustrative example: FK Com
line centroid shifts with time
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Summary
coherently reduced datasets with extraordinarily detailed timing and spectral information
multiple, independent, simultaneous data streams
will be extended to other types of objects (e.g., AGNs), observed with other missions (e.g., XMM-Newton/RGS)
test bed for deep (as opposed to broad) analysis methods
e.g., not just detect a transient, but study its characteristics in spectral lines formed at different temperatures
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