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Solar-B X-ray Telescope (XRT)

Explore the mysteries of the solar chromosphere and corona with X-ray Telescope (XRT) observations to study magnetic activities, heating processes, and dynamical events. Discover the importance of temperature diagnostics and coordinated observations in discerning between different types of coronal loops. Learn about the unique characteristics and capabilities of the Solar-B/XRT instrument in observing and analyzing the Sun's dynamic phenomena.

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Solar-B X-ray Telescope (XRT)

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  1. XRT Solar-B X-ray Telescope (XRT) R. Kano (NAOJ) and XRT Team STEREO/Solar-B Workshop

  2. Dynamics in Chromosphere & Corona Magnetic Activities at Photosphere Coronal Activities Solar-B Science EIS http://sxt4.mtk.nao.ac.jp/xrt/photo/optio/20040915/IMGP1817.JPG SOT XRT “Coronal Heating” How are coronal structures heated? STEREO/Solar-B Workshop 2004/09/15

  3. Targets of XRT Observations Coronal Loop Structures & Coronal Loop Heating • Photosphere/Corona Coupling • Can a direct connection be established between coronal and photospheric events? • Coronal Heating • How do coronal structures brighten? • Flare Energetics • What are the relations to the photospheric magnetic fields? • CMEs, Jets and other coronal dynamical events STEREO/Solar-B Workshop

  4. SXT Loops vs. EIT/TRACE Loops SXT loops in active regions EIT Image • Are they really different? • Are they heated in a different way? • We would like to observe all of the coronal plasma with a single telescope. • However, we would like to distinguish betweenSXT loops and EIT/TRACE loops.(Importance of temperature diagnostics.) highest T Density est. from EM Temperature highest T Isothermal STEREO/Solar-B Workshop Kano & Tsuneta (1996, PASJ) Aschwanden et al. (1999 &2000, ApJ)

  5. SXT Loops vs. EIT/TRACE Loops SXT loops in active regions EIT Image • Do SXT loops have a dense plasmaat the top? • Is it an apparent feature in a loop • (by change of filling factor)? • EIS can derive the coronal density with density-sensitive line pairs.(Importance of the coordinated observationbetween EIS and XRT.) Density est. from EM Temperature highest T highest EM Hydrostatic STEREO/Solar-B Workshop Kano & Tsuneta (1996, PASJ) Aschwanden et al. (1999 &2000, ApJ)

  6. Solar-B/XRT vs. Yohkoh/SXT STEREO/Solar-B Workshop

  7. XRT characteristics • Temperature Response • TRACE-like image and SXT-like image • Field-of-View and Spatial Resolution • Focus Mechanism • Observation control by MDP • Table Observation • Image Compression • Time Cadences • Preflare Buffer STEREO/Solar-B Workshop

  8. X-ray Analysis Filters • XRT has 9 X-ray analysis filters and a G-Band filter. STEREO/Solar-B Workshop

  9. SXT-like TRACE-like XRT Temperature Response STEREO/Solar-B Workshop

  10. 384”x384” EIS SOT 1024”x1024” Field of View (FOV) XRT • To point SOT at a certain target on the solar disk, we have to change Solar-B pointing. Therefore, XRT will not always observe the full solar disk. • Many varieties of FOV size are available. • Especially, for high-res.- observation, we recommend FOV= 1024”x1024” around CCD center. 2048”x2048” STEREO/Solar-B Workshop

  11. Importance of Wide FOV • Moreton waves tend to propagate along the global magnetic fields. • X-ray waves also propagate with Moreton waves. STEREO/Solar-B Workshop

  12. Field of View (FOV) XRT • To point SOT at a certain target on the solar disk, we have to change Solar-B pointing. Therefore, XRT will not always observe the full solar disk. • Many varieties of FOV size are available. • Especially, for high-res.- observation, we recommend FOV= 1024”x1024” around CCD center. 1024”x1024” 2048”x2048” STEREO/Solar-B Workshop

  13. Aberration at Different Focus Pos. (Only Geometrical Optics) ϕ512” ϕ1024” RMS=ϕ1” Distance from the Center STEREO/Solar-B Workshop

  14. Observation Tables Observation of XRT XRT Mission Data Processor Autonomous Functions Exposure Control Region Selection Flare Detection SOT Data Recorder Image Compression Pre-Flare Buffer EIS STEREO/Solar-B Workshop

  15. Image Compression • MDP can compress the image data.Observer selects the following options. • No compression • DPCM (lossless) compression • JPEG (lossy) compression • Q-factor = 98, 90, … , 65. STEREO/Solar-B Workshop

  16. 30sec AR 10min 50min AR 40sec Narrow Wide 3min20sec Typical Time Cadences • typical data rate for XRT ~ 600 k pixel / min • ex.1: Continuous Observation for AR • AR FOV = 384”×384”, 1”-res. • ex.2: High-Speed Observation for AR • AR FOV = 384”×384”, 1”-res. • ex.3: Combination of Narrow and Wide FOV • Narrow FOV = 384”×384” , 1”-res. • Wide FOV =2048”×2048”, 4”-res. • .

  17. Pre-flare Observation Shimojo　（ASJ 1999 autumn） FOV = 256”x256”, 1”-res. Time Cadence = 10 ~ 20 sec for a filter pair STEREO/Solar-B Workshop

  18. Flare Observation XRT Intensity • XRT • Switch the current observation to Flare one. • Lock the Pre-Flare Buffer. • (There is a option not to switch to Flare obsevation.) • XRT • Detect a flare. • Report the location to all telescope. • SOT • Switch the current observation to Flare one,if the flare location is in SOT-FOV. • (There is a option not to switch to Flare obsevation.) • EIS • Switch the current observation to Flare one,if the flare location is in EIS-FOV. • (There is a option not to switch to Flare obsevation.) STEREO/Solar-B Workshop

  19. Solar-B/XRT vs. STEREO/EUVI STEREO/Solar-B Workshop

  20. Summary • XRT has high sensitivity for low (1MK) temperature plasma, as well as high temperature plasma. • XRT has the highest spatial resolution as GI imager. Pixel Size = 1 arcsec • Observation Tables respond to various observations. • Autonomous functions support XRT automatic operation. • Observers can select types of Image Compression. • Built-in visible light optic allows us to align XRT images with SOT images with sub-arcsec accuracy. STEREO/Solar-B Workshop

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