Observational Cosmology
The study of the origin, evolution, and structure of our Universe.
![](https://www.epfl.ch/research/domains/astrophysics/wp-content/uploads/2022/06/Abell370Arcs_HubbleAndreo_960-960x864.jpg)
Research methods in observational cosmology:
![Astronomers think that in the future the "Cheshire Cat" group will become what is known as a fossil group, a gathering of galaxies that contains one giant elliptical galaxy and other much smaller, fainter ones. Today, researchers know each "eye" galaxy is the brightest member of its own group of galaxies and these two groups are racing toward one another at over 300,000 miles per hour. Data from Chandra (purple), which has been combined with optical data from Hubble, show hot gas that has been heated to millions of degrees, which is evidence that the galaxy groups are slamming into one another. Chandra's X-ray data also reveal that the left "eye" of the Cheshire Cat group contains an actively feeding supermassive black hole at the center of the galaxy.](https://www.epfl.ch/research/domains/astrophysics/wp-content/uploads/2022/06/cheshirecat_chandra_complg_1024-384x216.jpg)
Gravitational lensing
Short description of gravitational lensing and cosmology.
![](https://www.epfl.ch/research/domains/astrophysics/wp-content/uploads/2022/06/im-384x216.jpg)
21cm intensity mapping
Trace HI structure in the Universe to measure matter power spectrum and baryon acoustic oscillations
![](https://www.epfl.ch/research/domains/astrophysics/wp-content/uploads/2022/07/BOSS_Illustration-384x216.jpg)
Galaxy & Quasar Clustering
Standard ruler and growth of structures
![](https://www.epfl.ch/research/domains/astrophysics/wp-content/uploads/2022/07/Lyman-alpha_forest-384x216.gif)
Lyman-Alpha Forest
Probing the intergalactic medium
![](https://www.epfl.ch/research/domains/astrophysics/wp-content/uploads/2022/07/eboss_map-384x216.png)
Spectroscopic Surveys
Probing the 3D map of galaxies and quasars in the Universe
![](https://www.epfl.ch/research/domains/astrophysics/wp-content/uploads/2022/06/lyman-alpha-e1656419657772-384x216.jpg)
Cosmological Simulations
Synthetic universes that mimic the observed large-scale structures
![](https://www.epfl.ch/research/domains/astrophysics/wp-content/uploads/2022/06/scd-384x216.jpg)
Extragalactic Distance Scale
Measuring distances and the Hubble constant using standard candles