Last Updated: 20181101

ISSI AtomicHelioStatistics Collaboration

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We are a group of Astronomers, Solar physicists, Atomic Physicists, and Statisticians. Our goal is to characterize the statistical and systematic errors in atomic databases, and figure out the proper methods to propagate them through typical solar and stellar spectral analyses.

The group was formed in response to a call for projects by the International Space Science Institute (ISSI). Team members are Harry Warren (NRL; PI), Adam Foster (CfA) Chloe Guennou (Columbia), Connor Ballance (Queen's Univ) David Stenning (IAP), David van Dyk (Imperial), Fabio Reale (OAPA, Palermo), Frederic Auchere (Inst. Astr. Spatiale), Giulio Del Zanna (Cambridge), Inigo Arregui (Inst. Astr. de Canarias), Jessi Cisweski (Yale), Mark Weber (SAO), Nathan Stein (Spotify), Randall Smith (SAO), Veronique Delouille (Royal Obs. Belgium), Vinay Kashyap (SAO), and Xixi Yu (Imperial). Our ISSI team webpage is at


2016 Oct 6-7 [@CfA]
We will hold a min-Workshop [url] to discuss progress on algorithm development and papers.
2016 Apr 13-15 [@Bern]
We held a second interperson meeting [url] to discuss progress and results on toy problem (see notes from May 2015 meeting) [url] and figure out future directions.
Meeting Summary [.html]
Action Items [.html]
2015 May 11-13 [@Bern]
"Toy" problem to focus on for Bern meeting: density sensitive line ratios [.html]
Presentation slides:
  1. Overview (H. Warren) [.pdf]
  2. V. Kashyap [.pdf]
  3. G. Del Zanna [.pdf]
  4. R. Smith [.pptx]
  5. M. Weber [.pdf]
  6. N. Stein [.pdf]
  7. D. van Dyk [.pdf]
  8. D. Stenning [.pdf]
  9. J. Cisewski [.pdf]
  10. C. Guennou [.pdf]
  11. F. Auchere [.pdf]
  12. F. Reale [.pdf]
  13. I. Arregui [.pdf]
    Notes [.pdf]
  14. H. Warren [.pdf]
  15. Summary and wrap-up (H. Warren) [.pdf]
Pictures from workshop dinner [url]
Meeting summary and action items [.pdf]
2014 Aug 11 [Telecon]
Resolved: make a web site for the collaboration

Papers, Presentations, and databases of interest

Incorporating Uncertainties in Atomic Data into the Analysis of Solar and Stellar Observations: a Case Study in FeXIII, Yu, X., Del Zanna, G., Stenning, D.C., van Dyk, D.A., Warren, H.P., Weber, M.A., and ISSI Collaboration, 2019, Astrostatistics Interest Group: Student Paper Award, JSM 2019
Abstract [url]
Presentation [.pdf]
Incorporating Uncertainties in Atomic Data into the Analysis of Solar and Stellar Observations: A Case Study in FeXIII, Yu, X., Del Zanna, G., Stenning, D.C., Cisewski-Kehe, J., Kashyap, V.L., Stein, N., van Dyk, D.A., Warren, H.P., & Weber, M., 2018, ApJ, 866, 146
DOI:10.3847/1538-4357/aadfdd [url]
manuscript [.pdf]
Atomic Uncertainties into Data Analysis, Kashyap, V., 2018, talk at AtomDB Workshop, CfA, 2018 Nov 01
Slides [.pdf]
Multistage Anslysis on Solar Spectral Analyses with Uncertainties in Atomic Physical Models, Yu, X., 2018, talk at CHASC, 2018 Oct 23
Abstract and slides [url]
Can we deal with Atomic Data Uncertainties?, Kashyap, V., 2018, talk to Stellar Dynamo Grou, CfA, 2018 May 7
Slides [.pdf]
Incorporating Uncertainties in Atomic Data Into the Analysis of Solar Observations, Yu, X., 2018, talk at SSXG, CfA, 2018 Apr 19
Slides [.pdf]
Statistical methods in Solar Spectral Analyses with Uncertain Atomic Physical Models, Yu, X., 2018, talk at CHASC, 2018 Apr 3
Abstract and slides [url]
The Light at the End of the Tunnel: Uncertainties in Atomic Physics, Bayesian Inference, and the Analysis of Solar and Stellar Observations, Warren, H., and the ISSI Team, at SPD 2016 (2016may)
Poster [.pdf]
GitHub repository for density-sensitive line ratios problem [url]
Original proposal [Internal] [.pdf]
< Solar & Stellar | Atomic | Computations | Statistics >

Solar and Stellar Observational and Analysis

Introductory notes by Harry Warren (2014aug)
Illustrative movies
Solar physics and solar data [.pdf]
Observation and Modeling of Coronal ``Moss'' With the EUV Imaging Spectrometer on Hinode, Warren, H.P., Winebarger, A.R., Mariska, J.T., Doschek, G.A., & Hara, H., 2008, ApJ, 677, 1395
2008ApJ...677.1395W [ADS]
IOP [.pdf]
Modeling the Ne IX Triplet Spectral Region of Capella with the Chandra and XMM-Newton Gratings, Ness, J.-U., Brickhouse, N.S., Drake, J.J., & Huenemoerder, D.P., 2003, ApJ, 598, 1277
2003ApJ...598.1277N [ADS]
IOP [.pdf]
On the Nature of the ``Moss'' Observed by TRACE, Martens, P.C.H., Kankelborg, C.C., & Berger, T.E., 2000, ApJ, 537, 471
2000ApJ...537..471M [ADS]
High-resolution Imaging of the Solar Chromosphere/Corona Transition Region, Berger, T.E., De Pontieu, B., Schrijver, C.J., & Title, A.M., 1999, ApJ, 519, 97
1999ApJ...519L..97B [ADS]
Loop models of low coronal structures observed by the Normal Incidence X-Ray Telescope (NIXT), Peres, G., Reale, F., & Golub, L., 1994, ApJ, 422, 412
1994ApJ...422..412P [ADS]

Atomic Databases and Calculations

AtomDB: Atomic Data for Astrophysicists
WebGuide -- for looking up specific lines and transitions
CHIANTI atomic database
Imaging and Spectroscopic Observations of a Transient Coronal Loop: Evidence for the Non-Maxwellian kappa-Distributions, Dudik, J., Mackovjak, S., Dzifcakova, E., Del Zanna, G., Williams, D.R., Karlicky, M., Mason, H.E., Lorincik, J., Kotrc, P., Farnik, F., & Zemanova, A., 2015, ApJ, in press
1505.04333 [arXiv]
Spectrum Ultimum Capellae: 15 Years of Chandra Observations of Capella, Kashyap, V., Drake, J., Smith, R., & Wargelin, R., 2014, at 15 Years of Chandra Symposium, 18-21 Nov 2014, Boston, MA
Compilation of detected lines in 1.2 Msec of Chandra observations of Capella
Poster [.pdf]
A New Calculation of Ne IX Line Diagnostics, Smith, R.K., Chen, G., Kirby, K., & Brickhouse, N.S., 2009, ApJ, 700, 679
2009ApJ...700..679S [ADS]
IOP [.pdf]
Collisional Plasma Models with APEC/APED: Emission-line Diagnostics of Hydrogen-like and Helium-like Ions, Smith, R.K., Brickhouse, N.S., Liedahl, D.A., & Raymond, J.C., 2001, ApJ, 556, L91
2001ApJ...556L..91S [ADS]
IOP [.pdf]

Computations and Simulations

MHD modeling of coronal loops: the transition region throat, Guarrasi, M., Reale, F., Orlando, S., Mignone, A., & Klimchuk, J.A., 2014, A&A, 564, 48
2014A&A...564A..48G [ADS]
Can the Differential Emission Measure Constrain the Timescale of Energy Deposition in the Corona?, Guennou, C., Auchere, F., Klimchuk, J.A., Bocchialini, K., & Parenti, S., 2013, ApJ, 774, 31
2013ApJ...774...31G [ADS]


A Revolution in DEM Analysis (with Application to Nanoflare Heating), Weber, M., 2014, at Hinode-8/LWS/IRIS Science Meeting 2014
High level summary of the unique strengths of the Convex Hull + Singular Value Decomposition framework for solving DEM reconstructions
Slides [.pdf]
A Novel Framework for Differential Emission Measure Analysis of the Solar Corona, Weber, M.A., 2015+, ApJS, submitted
Manuscript [internal] [.pdf]
A Fully Bayesian Method to Simultaneously Fit Calibration Products and Model Parameters in X-ray Spectral Analyses, Xu, J., et al., 2014, ApJ, 794, 97
Paper [.pdf]
Accounting for Calibration Uncertainties in X-ray Analysis: Effective Areas in Spectral Fitting, Lee, H., et al., 2011, ApJ, 731, 126
Paper [.pdf]
Incorporating Atomic Data Errors in Stellar DEM Reconstruction, Kang, H., van Dyk, D.A., Kashyap, V.L., & Connors, A., 2005, in ``X-Ray Diagnostics of Astrophysical Plasmas: Theory, Experiment, and Observation'', AIP Conference Proceedings, Volume 774, p.373
Markov-Chain Monte Carlo Reconstruction of Emission Measure Distributions: Application to Solar Extreme-UltraViolet Spectra, Kashyap, V. & Drake, J.J., 1998, ApJ, 503, 450
Paper [.pdf]
1998ApJ...503..450K [ADS]
< Solar & Stellar | Atomic | Computations | Statistics >


2014-jun-17: set up page.
2014-nov-19: site goes public
2014-nov-26: added Kang et al. writeup pdf, links to AtomDB and CHIANTI
2015-mar-05: added link to ISSI team page
2015-mar-17: added link to Bern toy problem page
2015-apr-24: added draft schedule for 2015 May Bern meeting
2015-may-13: added presentation slides from talks at Bern meeting
2015-may-19: added a number of papers of interest and reorganized the structure
2015-may-22: added summary of, and action items from, May 2015 meeting
2015-may-27: added group photos
2015-may-28: moved photos to separate page, newest item gets an anchor
2016-feb-01: added agenda stub for Apr 2016 meeting, added link to GitHub repository
2016-may-13: added links to Apr 2016 meeting
2016-may-27: added Warren SPD2016 poster
2016-aug-19: added link to CfA mini-Workshop page
2018-may-07: updated collaborations list, added slides from Xixi Yu presentation to CHASC and SSXG, and Vinay Kashyap presentation to Stellar Dynamo group

ISSI Atomic/Helio/Stats
    Solar & Stellar

We make the errors, so you don't have to.
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