ISA 2025 Astrophysics Projects

This repository contains Python notebooks, datasets, and final reports for two astrophysics research projects completed as part of the India Space Academy (ISA) 2025 Summer School. These projects explore the dynamical mass of galaxy clusters and the estimation of cosmological parameters using real observational data from SDSS and Pantheon+SH0ES datasets.

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🧠 Projects Overview

1️⃣ Estimating the Dynamical Mass of a Galaxy Cluster

• Objective: Determine the mass of a galaxy cluster using spectroscopic redshift data from SDSS.
• Approach:
  • Filter cluster members using redshift dispersion (±3σ).
  • Calculate cluster velocity dispersion and physical size.
  • Apply the virial theorem to estimate dynamical mass.
  • Compare luminous vs. dynamical mass to infer dark matter presence.
• Result: Mass-to-light ratio ~136, confirming a dominant dark matter component.

2️⃣ Estimating Cosmological Parameters from Type Ia Supernovae

• Objective: Estimate the Hubble constant (H₀), matter density (Ωₘ), and universe age using Type Ia supernovae.
• Approach:
  • Use the Pantheon+SH0ES dataset.
  • Fit a flat ΛCDM cosmological model using non-linear least squares.
  • Analyze residuals and redshift-dependent trends.
  • Explore the effect of Ωₘ on H₀ and the age of the universe.
• Result: Estimated H₀ = 72.97 ± 0.26 km/s/Mpc, age ≈ 12.36 Gyr. Results align with late-universe measurements and contribute to the Hubble tension discussion.

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⚙️ Requirements

Make sure you have Python 3.8+ and the following libraries installed:

pip install numpy pandas matplotlib scipy astropy

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📊 Sample Visualizations

• 📈 Redshift histograms and velocity dispersion plots for galaxy clusters.
• 🌌 Hubble diagram and residuals for supernova-based cosmology fits.
• 📋 Tables showing how H₀ and universe age vary with Ωₘ.

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🧾 Certification

This work was conducted under the guidance of India Space Academy, and officially certified as part of the ISA 2025 Summer School on Astronomy and Astrophysics.

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👤 Author

• Shamanthak Reddy Mallu
• BITS Pilani Hyderabad Campus
• ISA Admission Number : 554265

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🙌 Acknowledgments

• 🛰️ India Space Academy (ISA) for organizing the Summer School and providing datasets
• 🔭 Sloan Digital Sky Survey (SDSS) for galaxy data
• 🌠 Pantheon+SH0ES Collaboration for supernovae data and cosmology resources