Cal Stats

(Chair: Vinay Kashyap)

A forum for the discussion of statistical, methodological, and algorithmic issues that affect the calibration of astronomical instruments, of how calibration data are used in data analysis, and how the analysis results are interpreted. 

Mailing list: iachec-calstat@cfa.harvard.edu
Current members: List of members

Talks/Meetings | Library

  



Talks

  • 2022 May 24: Herman Marshall on Progress in Calibration Concordance at IACHEC Spring Workshop
  • 2021 Dec 1: Sam Sweere on AI-Assisted Super-Resolution and De-Noising for XMM-Newton EPIC-pn
  • 2021 Jun 7: Yang Chen on Systematic Uncertainties in Multi-Telescope Observations at AAS 238
  • 2020 Dec 8: Diab Jerius on Doing the Hokey-Pokey, or Deriving Statistical errors for Measurements of the Chandra X-ray Observatory PSF at CHASC
  • 2020 Sep 8:Herman Marshall & Yang Chen on Concordance: In-flight Calibration of X-ray Telescopes without Absolute References at CHASC
  • 2020 Aug 6: Kristin Madsen X-ray data and its many challenges at JSM 2020
  
 
Wednesday, 2021 December 1
6-7am PST / 9-10am EST / 2-3pm GMT / 3-4pm CET / 7:30-8:30pm IST / 11pm-midnight JST
AI-Assisted Super-Resolution and De-Noising for XMM-Newton EPIC-pn
Sam Sweere (XMM/SOC, ESAC)
Abstract: The field of AI image enhancement has been rapidly evolving over the last few years and is able to produce impressive results on non-astronomical images. My research looks at applying these techniques to enhance XMM-Newton X-ray images. Specifically, having an AI-model increase the resolution and denoise the images with the goal of increasing their scientific value. During the talk, I will touch on the processes, initial results, and challenges of super-resolution AI models for XMM-Newton.
Presentation slides [.pdf]
Presentation video — https://smithsonian.zoom.us/rec/share/4k-ko9F5rJFQi4eVKTuSfKjtCrfb_tOHEdrinwvn4BzI8PbOqfuSdKDI8oTmP_VW.7JwN2Y10kK0aV_j1 [zoom]
 

  



Recent Working Group Meetings

2024 May 13 (IACHEC XVI)
2023 Apr 25 (IACHEC XV)
2022 Jul 1
2021 Nov 1
2020 Dec 1

  


2024 May 13 during IACHEC XVI

Combined CalStats and Hi-Res WG Special Session 9:30-11am CEST

  • Concordance Update by Herman Marshall
  • Polarimetry Statistics by Herman Marshall
  • HR1099 line fluxes and locations Chandra/XRISM by Vinay Kashyap and Eric Miller

Summary Reports May 16 9am-Noon CEST

  • CalStats Working Group Report, by Vinay Kashyap

  


2023 Apr 25 during IACHEC XV

CalStats Part I 9-10:30am CEST

CalStats Part II 4:10-6pm CEST

Summary Reports Apr 27 9am-Noon CEST

  


2022 Jul 1

6-8am PDT / 9-11am EDT / 2-4pm BST / 3-5pm CEST / 8:30-10:30pm IST / 11pm-1am(+1d) CT / Midnight-2am(+1d) JST
iachec.org/calibration-statistics/#2022jul01

Agenda:
To discuss polarization statistics (led by H.Marshall) and probabilistic background removal (led by S.Ehlert)

Slides:

  


2021 Nov 1

iachec.org/calibration-statistics/#2021nov1

Agenda:
Pandemic report [arXiv]
— Concordance update
— Coordination with Background, HiRes, Timing WG

  


2020 Dec 1

6-8am PST / 9-11am EST / 2-4pm GMT / 3-5pm CET / 7:30-9:30pm IST / 10pm-Midnight CT / 11pm-1am(+1d) JST
iachec.org/calibration-statistics/#2020dec1

A follow-up to the IACHEC 2020 Online Symposium, this two-hour meeting is designed to give more opportunity for detailed discussions. Each presenter will have approximately 15 min, including discussion time. The goal here is not to have a parade of speakers, but to allow time for Q&A and discussions.

Agenda
Moderator: Terry Gaetz (CfA)

Video [.mp4]
Discussion chat log [.txt]


  



A Curated Library

Atomic Data Uncertainty
Background
Best Practices
Calibration Uncertainty and Concordance
Polarization Statistics
Miscellaneous
 

Atomic Data Uncertainty

to understand the nature of the uncertainties present in compilations and measurements of atomic lines, emissivities, and other spectral features, and determine what effects they have and how to incorporate them during analyses.

Background

to compile models of instrument background and provide scripts and recipes for how to use them in spectral, spatial, and timing analyses.

A compilation of studies, models, packages, and scripts dealing with the non X-ray backgrounds from various instruments is maintained at the wiki page.

Statistics Best Practices

to describe and develop principled methods to handle the analysis of data such that biases and improper or imprecise interpretations are minimized, and to provide tutoorials and guides.

Calibration Uncertainty, Systematics, and Concordance

to establish the magnitudes of the statistical and systematic instrument uncertainties, and develop methods to incorporate them or correct for them in analyses.

Polarization Statistics

  • Marshall (2022+, in prep) (Poisson likelihood with background, nonuniform exposure angle, mRMF)
  • Gonzales-Caniulef et al. 2022 (likelihood method for pulsars)
  • Di Marco et al. 2022 (event weights using IXPE track ellipticities)
  • Marshall 2022 (likelihood method, modeling modulation facor)
  • Marshall 2021
  • Peirson et al. 2021 (ML to get better modulation factor)
  • Strohmayer 2017 (fitting IQU spectra in XSPEC, mRMF)
  • Kislat et al. 2015 (unbinned analysis, event weighting)
  • Elsner, O’Dell & Weisskopf, 2012 (Gaussian statistics, background)

Miscellaneous

a catch-all category to handle other items of interest that do not fit in one of the above categories.