Lesson Plan

• Describe the two primary mechanisms of X‑ray production (bremsstrahlung and characteristic emission).
• Explain how X‑ray observations reveal physical conditions in hot astrophysical plasmas.
• Identify major X‑ray astronomy missions and the types of cosmic sources they study.
• Compare different X‑ray detector technologies and their energy‑resolution capabilities.
• Apply the virial theorem to estimate galaxy‑cluster masses from X‑ray temperature measurements.

• Projector with presentation slides
• Whiteboard and markers
• Handout summarizing X‑ray production mechanisms and detector types
• Access to an online X‑ray image archive (e.g., Chandra Data Archive)
• Calculator or spreadsheet for simple mass‑temperature calculations
• Optional: small model of grazing‑incidence mirror for demonstration

Begin with a striking image of a galaxy cluster captured in X‑rays, asking students what makes these objects glow at such high energies. Recall prior knowledge of the electromagnetic spectrum and photon energy. Explain that by the end of the lesson they will be able to describe how X‑rays are produced and how astronomers use them to probe the Universe.

1. Do‑now (5'): Students list astrophysical phenomena that emit high‑energy radiation (quick check).
2. Mini‑lecture (15'): Explain bremsstrahlung and characteristic X‑ray production, including key equations (brief).
3. Interactive activity (10'): In groups, match X‑ray missions with their primary science goals using the handout (peer discussion).
4. Detector showcase (10'): Demonstrate scintillator, CCD, and TES detectors with slides; discuss energy‑resolution differences.
5. Data analysis task (15'): Students calculate a rough galaxy‑cluster mass using the virial‑theorem formula and a provided temperature value.
6. Class discussion (5'): Reflect on how X‑ray observations inform cosmology (dark energy, large‑scale structure).

Summarise that X‑rays arise from extreme temperatures and energetic processes, and that modern detectors allow precise energy measurements. For the exit ticket, each student writes one way X‑ray astronomy contributes to our understanding of the cosmos. Homework: read a short article on the upcoming XRISM mission and prepare a question for the next class.