131. Astrostatistics in High Energy Astrophysics
7:30pm9:00pm, 8 Apr 2013, DeAnza Ballroom
This astrostatistics session will honor the
memory of Alanna Connors.
Alanna was a pioneer in the investigation and development of statistical
methods required for the analysis of high energy data. The session
will provide a historical perspective on Bayesian methods, highlight
the topics where the contribution made by Alanna were particularly
important, summarize current analysis challenges and discuss future
perspectives.
Program
 Chair: Herman Marshall (MIT)

 Retrospective [20 min]
 131.01 Alanna Connors and the Origins of Principled Data Analysis
 Jeffrey D. Scargle (NASA/Ames)
 Abstract: Alanna was one of the most important pioneers
in the development of not just sophisticated algorithms for analyzing
astronomical data but more importantly an overall viewpoint
emphasizing the use of statistically sound principles in place
of blind application of cookbook recipes, or black boxes.
I will outline some of the threads of this viewpoint, emphasizing
time series data, with a focus on the importance of these
developments for the Age of Digital Astronomy that we
are entering.
 Presentation slides [.pdf]

 Topics [5+2 min]
 131.02 Promoting widespread use of Bayesian analysis
 Keith Arnaud (NASA/GSFC)
 Abstract: I will discuss incorporating Bayesian analysis in XSPEC
and what is required for them to become the default option for high energy
astrophysicists.
 Presentation notes [.txt]

 131.03 Hypothesis Tests
 Aneta Siemiginowska (CfA)
 Abstract: I will comment on statistical methods for hypothesis
testing, highlighting the potential issues with using posterior predictive
pvalues or Bayes Factors.
 Presentation slides [.pdf]

 131.04 Using Bayesian Blocks to Trigger on Very High Energy Flares from Blazars
 James Chiang (Stanford/SLAC)
 Abstract:
Owing to the continuous scanning observation mode of the Fermi
satellite, the Large Area Telescope (LAT) is able to provide allsky
coverage on 3hour time scales. However, this observing mode induces
strong exposure modulations for any given location on the sky, making
detection of transients on time scales of minutes to hours from
objects problematic. I will discuss the application of the Bayesian
Blocks algorithm to LAT data in a way that accounts for these exposure
variations and show how the technique might be used to trigger on
bright GeVTeVflaring blazars such as Mrk 421.
 Presentation slides [.pdf]

 131.05 A Statistical Approach to Recognizing Source Classes for Unassociated Sources in the Second FermiLAT Catalog
 Maria Elena Monzani (Stanford/SLAC)
 Abstract: We have developed a new and innovative technique
to classify Fermi sources based solely on their observed gammaray
properties. Our technique, based on Classification Trees, uses the
properties of known objects to build a classification analysis which
provides the probability for an unidentified source to belong to a
given astronomical class (Pulsar, AGN,...). We have applied this
technique to the second FermiLAT source catalog (2FGL), and computed
a classification probability for each unidentified source. This provides
a clearer picture of the unidentified source population and extends the
number of interesting candidate objects, thus helping the community in
scheduling multiwavelength observations.
 Presentation slides [.pdf]
 Extended illustration of analysis and methods are given in Ferrara et al. (2012 Fermi & Jansky Proceedings, arXiv/1206.2571)

 131.06 LIRA: Lowcounts Image Reconstruction and Analysis
 Nathan M. Stein (Harvard)
 Abstract:
I will discuss LIRA, an R software package for multiscale nonparametric
image analysis in high energy astrophysics. LIRA uses Markov chain Monte
Carlo to simultaneously fit an image and the necessary smoothing
parameters, allowing for quantification of the standard error of the fitted
image and evaluation of the goodnessoffit of a proposed model.
 Presentation slides [.pdf]

 131.07 Systematic Errors
 Vinay L. Kashyap (SAO)
 Abstract: I will talk about methods to incorporate
systematic errors into astrostatistical analysis, and discuss
future prospects. In particular, I will point out how the pyBLoCXS
algorithm lends itself to adding feedback, generalize to higher
dimensions, and parameterize the sources of systematics.
 Presentation slides [.pdf]

 Prospective [20 min]
 131.08 Possessing the field: Alanna Connors and the future of principled data analysis
 Thomas J. Loredo (Cornell)
 Abstract:
Alanna emphasized the importance of adopting sound principles to guide
statistical analysis of astronomical data. Her work and the work of her
many collaborators and colleagues demonstrates the value of a principled
approach. I will highlight two threads in her work: hierarchical
Bayesian modeling, and nonparametric Bayesian modeling. I will note how
these powerful ideas have influenced recent astrostatistics research,
and point to how they might profitably merge for addressing the emerging
problems of synoptic timedomain astronomy via Bayesian functional data
analysis.

Posters and talks of interest
 108.10. First Statistical Tests for Clumpy Torii Models: Constraints from RXTE Monitoring of Seyfert AGN
 Alex Markowitz; Mirko Krumpe; Robert Nikutta
 117.01. Xray Reflected Spectra from Accretion Disk Models: A Complete Grid of Ionized Reflection Calculations
 Javier Garcia; Thomas Dauser; Christopher S. Reynolds; Timothy R. Kallman; Jeffrey E. McClintock; Ramesh Narayan; Joern Wilms; Wiebke Eikmann
 117.02. Twotemperature and ModelIndependent Differential Emission Measure Distributions: The Emperor's New Clothes?
 Kenneth G. Gayley
 117.04. Statistical Methods in XSPEC
 Keith A. Arnaud
 117.05. The HEASARC in 2013 and Beyond: NuSTAR, AstroH, NICER...
 Stephen A. Drake; Alan P. Smale; Thomas A. McGlynn; Keith A. Arnaud
 117.06. Application of an Improved Event Reconstruction and Imaging Approach for Compton Telescopes to Crab Measurements by NCT and COMPTEL Using MEGAlib
 Andreas Zoglauer; Steven E. Boggs
 117.07. Artificial Neural Networks as a Tool to Classify the 2FGL Unassociated Sources
 David Salvetti
 117.08. Earth Occultation Imaging of the Low Energy Gammaray Sky with GBM
 James Rodi; Michael L. Cherry; Gary L. Case; Mark H. Finger; Peter Jenke; Colleen Wilson; Ascension CameroArranz; Vandiver Chaplin
 117.09. Bayesian Methods in Sherpa
 Aneta Siemiginowska; Thomas L. Aldcroft; Vinay Kashyap
 126.16. Population Synthesis of Radio and Yray Normal, Isolated Pulsars Using Markov Chain Monte Carlo
 Caleb Billman; Peter L. Gonthier; Alice K. Harding
 127.23. GammaRay Bursts: Pulses and Populations
 Thomas J. Loredo; Jon E. Hakkila; Mary Beth Broadbent; Ira M. Wasserman; Robert L. Wolpert
 204.03. A Statistical Approach to Identifying Compact Objects in Xray Binaries
 Saeqa D. Vrtilek
Organizers: Aneta Siemiginowska, Vinay Kashyap