Solar Soft X-ray Irradiance with Hinode/XRT

Project descriptions

With this archive, we can study solar activities in terms of the Sun's radiation in soft X-ray wavelengths. In this project, we will process the XRT/SCIA images taken from 2006 to present to derive the soft X-ray irradiance during this period. We will learn how to process Hinode/XRT FITS data for quantitative analysis using the data analysis software IDL(Interactive Data Language): data selection, derivation of temperature and emission measure, calculation of the XRT irradiance in the physical unit (W/m^2), etc. This project is continued from 2021. This year, we will put emphasis on the data calibration to correct characteristic change of the instrument over 15 years of operation, and comparison with the observations by other instruments measuring the solar cycle variation.

As a bonus, the student will have a few opportunities to watch and learn how an international satellite project like Hinode is operated. As one of US institutes participating the Hinode satellite operation, we have a duty week in July, in which we take control of the XRT observation.

Weekly goals

• Week 1 (5/31 -- 6/3) :
  • Get familiar with IDL (Bootcamp by C. Zhu on 6/1, 9am- @room#258)
  • Read "Encyclopedia of the Sun" to study background of the project (sections 8.4, 8.5.).
  • Introduction to Hinode project and XRT instruments.
  • Introduction to XRT data handling with IDL.
    • read XRT level0 data (sample_read.pro)
    • calibrate XRT data (sample_prep.pro)
    • make a composite image(sample_comp.pro)

• Week 2 (6/6 -- 6/10) :
  • Get to know about SCIA data.
  • Understand the project goal and steps to get there.
    • step 1: data selection (find usable image pairs of thin_Be and Al_mesh)
    • step 2: collect total intensity within 1.1 Rs.
    • step 3: derive averaged temperature(Te) and Emisison Measure(EM) for each pair.
    • step 4: convert Te and EM to solar irradiance in the unit of W/m^2.
  • Finished until Step 1 and Step 2.
  • Preparation for the short presentation on Friday 2pm. (well done!)
  
  
• Week 3 (6/13 -- 6/17) :
  • Learn about the Filter Ratio Method.
  • Calculate Te and EM for the additional months (with Chianti ver.9).
  • Calculate Te and EM with Chianti DB ver 10.0, assuming different abundance sets, for the whole mission (great job!).
  • Learn about how to make IDL procedures and run them in sequence.
  
  
• Week 4 (6/20 -- 6/24) :
  • Make mission-long over plots showing different Chinanti versions or different abundance asumption.
  • Calculate Te and EM with a modified XRT effective area functions.
  • Start working on the investigation of the "height dependence" (SCIA data for 2021/10/16-17 might help).
  • Preparation for the 2nd bi-weekly meeting on Friday 2pm (well done!).
  
  
• Week 5 (6/27 -- 7/1) :
  • Process mission-long data with a modified XRT effective area functions.
  • Advance "height dependence" project.
  • Understand the method converting Te and EM to irradiance.
  
  
• Week 6 (7/6 -- 7/8) :
  • Preparation of mid-term presentation (excellent!).
  • Advance indelendent project (height depenence study).
  
  
• Week 7 (7/11 -- 7/15) :
  • Start converting Te and EM to Irradiance in W/m^2
  • Propose special observation to XRT to study high corona.
  • Sneak peek Hinode operation meeting (7/13 19:30-)
  • Advance independent project (find signal increase with radius).
  
  
• Week 8 (7/18 -- 7/22) : Concentrate to the independent project.
• Week 9 (7/25 -- 7/29) : Independent project + preparation of the final presentation
• Week 10 (8/1 -- 8/4) :
  • Final presentation! Excellently done!
  • Organizing/cleaning working directories.
  • Prepare final document of the project (like abstract of the science meeting presentation).

Resources

• Section 8.4 and 8.5 of "Encyclopedia of the Sun" by Kenneth R. Lang (2001) Cambridge University Press
• about XRT Synoptic Composite Images
• Other References
• IDL sample programs
• IDL Basics (old version, but still helps)

just a memo for the 6/9 meeting

memo for the 6/13 meeting

• The Filter Ratio Method
• XRT's effective area functions and spectral response functions
• XRT's CCD camera gain constant is 57 electrons/DN

memo for the 6/20 meeting

• an up-to-date atomic database and associated codes (IDL, Python),
• for the analysis of optically-thin line and continuum plasma emission (like solar corona).
• developed by a group of scientist from US(NRL) UK(Cambridge) and Italy(Arceri Astrophysical Obs.
• version 1 released in 1997.

memo for the 6/30 meeting

• free-free emission
• free-bound emission
• bound-bound emission

Solar X-ray radiation affecting to Earth

XRT response and filter ratio function corrected plots

note for the 7/11 meeting

note for 7/12 meeting

• XOB#1CE4 was prepared (and modified).
  • 0: dark images
  • 1: Al_mesh synoptic set (2ms/125ms/707ms/707ms/707ms /707ms)
  • 2: Al_poly synoptic set (12ms/177ms/1.41s/1.41s/1.41s /1.41s)
  • 3: thin_Be synoptic set (16ms/500ms/3.78s/3.78s/3.78s /3.78s/3.78s/3.78s)
  • repeat 1-3 for 5 times. → 2 times
• duration: 10min 28sec → 8min 28sec
• memory: 435 Mbits → 237 Mbits
• pointing: (-411.0, 847.0) --- same as HOP344 the 10th pointing [example: 2021/10/17 at 12:56UT ] ---.
  → (-530, 530) --- similar to the post bakeout pointing #4 ---
• keep the pointing for 15 min before moving to the next obs.

      Date & Time   Tracking  Offset-X Offset-Y */
         (UT)       Curve No.  (deg)    (deg)   */
2022/07/16 03:45:00    0     -00.1472  00.1472  /*  -530.0/  530.0 : # XRT high coronal structures. */
2022/07/16 04:00:00    0      00.0000  00.0000  /*     0.0/    0.0 : synoptic, shifted  23.5 min + HOP 349 */

note for 7/15 meeting

• Comparison of different calibration parameters on thin_Be filters:
  
  • no correction (except stray light subtraction from Al_mesh).
  • filter contamination correction only on Al_mesh.
  • filter contamination correction on Al_mesh and thin_Be (ver1).
  • filter contamination correction on Al_mesh and thin_Be (ver2: thin_Be thickness 2 times larger than ver.1).
  It turned out that change of thin_Be thickness does not affect the result. Will choose ver.1 as a representative value for thin_Be.
  
• Comparisons we will show in our final presentations:
  
  • Chianti ver 9 and 10 with coronal abundance.
  • Chianti ver 10 with different abundance sets (corona, hybrid, and photospheric).
  • With/without filter contamination correction (with Chianti ver 10, coronal abd). Comparare "step3" and "newcal2" data sets.

Examples of Abstract

• Takeda et al at Hinode 12th Science meeting 2018 Sept in Spain
• Takeda at AGU meeting 2020 Dec. (virtual)

Aki Takeda (Research Scientist, Dept. of Physics at MSU)