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Stingray PyAstro16

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.

Dr. Abbie Stevens

March 21, 2016
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Transcript

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

    View Slide

  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

    View Slide

  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

    View Slide

  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

    View Slide

  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

    View Slide

  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…

    View Slide

  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

    View Slide

  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!

    View Slide

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

    View Slide

  11. Progress on GIT

    View Slide

  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?

    View Slide

  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

    View Slide

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

    View Slide

  15. View Slide