Stingray PyAstro16

"Stingray: Time series methods for asronomical X-ray data that aren't fishy at all!"
A presentation at the Python in Astronomy 2016 workshop in Seattle.

Transcript

1. STINGRAY
   Time series methods for
   Astronomical X-ray Data
   that Aren’t fishy at all!
   Abbie Stevens
   @abigailStev
   

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2. X-ray variability
   —  X-ray binaries:
   can’t spatially resolve them
   —  Vary on timescales from
   tens of microseconds to
   months/years
   —  X-ray pulsations, zoology of quasi-periodic
   oscillations, broadband “peaked” noise
   —  Similar variability phenomena in gamma, optical,
   IR
   Figure: NASA
   

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3. How to Study X-ray
   Binaries
   Spectroscopy
   Timing
   Polarimetry??
   Γ1
   3.5
   3.4
   3.3
   3.2
   3.1
   3.0
   2.9
   2.8
   2.7
   2.6
   2.5
   2.4
   2.3
   2.2
   2.1
   2.0
   1.9
   1.8
   1.7
   100
   10
   1
   2.4
   2.2
   2.0
   1.8
   1.6
   1.4
   1.2
   1.0
   0.8
   0.6
   0.4
   0.2
   Fourier frequency f [Hz]
   2.1–15 keV
   PSD ×f [rms2
   × 102]
   IGR J17480 2446
   GX 17+2
   4U 1728 34
   Frequency x (RMS/Mean) Hz
   2 −1
   Frequency x (RMS/Mean) Hz
   2 −1
   Frequency x (RMS/Mean) Hz
   2 −1
   L
   b
   L
   b
   L
   b
   L
   h
   L
   hHz
   Frequency (Hz)
   kHz QPOs
   kHz QPO
   kHz QPO
   HBO
   HBO
   Figures: Grinberg et al ‘14, Done et al ‘07,
   Altamirano et al ‘12
   

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4. Variability analysis
   1016 1018 1020 1022 1024
   5000 104 1.5×104
   Count/sec
   Time (s)
   Start Time 10168 18:16:52:570 Stop Time 10168 18:17:08:180
   Bin time: 0.1562E−01 s
   Time domain
   Light curve
   Frequency domain
   Power spectrum
   FOURIER
   TRANSFORM
   

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5. X-ray Variability: Hard
   to see by eye
   1016 1018 1020 1022 1024
   5000 104 1.5×104
   Count/sec
   Time (s)
   Start Time 10168 18:16:52:570 Stop Time 10168 18:17:08:180
   Bin time: 0.1562E−01 s
   1700 1702 1704 1706 1708 1710
   2000 4000 6000 8000 104 1.2×104
   Count/sec
   Time (s)
   Start Time 12339 7:28:14:566 Stop Time 12339 7:29:32:683
   Bin time: 0.7812E−02 s
   Light curves
   

   View Slide

6. X-ray Variability: Hard
   to see by eye
   1016 1018 1020 1022 1024
   5000 104 1.5×104
   Count/sec
   Time (s)
   Start Time 10168 18:16:52:570 Stop Time 10168 18:17:08:180
   Bin time: 0.1562E−01 s
   1700 1702 1704 1706 1708 1710
   2000 4000 6000 8000 104 1.2×104
   Count/sec
   Time (s)
   Start Time 12339 7:28:14:566 Stop Time 12339 7:29:32:683
   Bin time: 0.7812E−02 s
   Light curves
   Power spectra
   

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7. Which analysis
   methods? ALL of them!
   —  Power spectra (periodograms)
   —  Fitting profiles to power spectra
   —  Periodic and quasi-periodic signal detection
   —  Dynamical power spectra
   —  Cross-/co-spectra, cross-correlation functions
   —  Averaged and frequency-resolved energy spectra
   —  Energy- or frequency-dependent time lags
   —  Rms and covariance spectra, coherence
   —  Bispectra, bicoherence, deadtime compensation,
   simulation support…
   

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8. Why make Stingray?
   —  Relatively small sub-field of astronomy
   —  Almost everyone uses (variations on) the same
   analysis techniques
   —  Most code is private, not documented, not properly
   tested, not maintained --- “black box” codes
   —  Unnecessary duplication of efforts, high threshold
   for entering the sub-field, difficult to get new
   students started
   

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9. Why make Stingray?
   —  Easier implementation of Bayesian methods &
   machine learning specific to X-ray (spectral-)timing
   —  Many analysis methods are already used in finance,
   music analysis, health care, neuroscience, and
   general signal processing
   —  Make an interface for applying those techniques to
   X-ray timing data
   —  Goal: become an Astropy affiliate package!
   

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10. Current modules
    Light curve
    Power spectrum
    Cross spectrum
    Pulsar tools
    Using travis for
    continuous
    integration
    

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11. Progress on GIT
    

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12. Support from the
    Community
    —  ESA support for GUI for exploratory data analysis
    —  Part of the Google Summer of Code!
    —  Likely support from HEASARC for developing data
    structures and I/O interface with existing & future
    missions
    —  Potential for interfacing with astropy.modeling and/
    or Sherpa spectral fitting package, especially for
    cross-spectral models
    —  YOU CAN HELP! Extending to IR, optical fast
    variability (spectral-)timing?
    

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13. Stingray Development
    https://github.com/StingraySoftware/stingray
    Contributors:
    Anurag Hota
    Evandro Martinez Ribeiro
    Himanshu Mishra
    John Swinbank
    Akash Tandon
    Project coordinators:
    Matteo Bachetti
    Paul Balm
    Daniela Huppenkothen
    Simone Migliari
    Abigail Stevens
    Mailing list:
    https://groups.google.com/forum/#!forum/
    spectraltiming-stingray
    

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14. We have a themesong!
    https://youtu.be/_w_Kx7EWNSA?t=6s
    

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15. View Slide