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Gamma-Ray Burst afterglows: illuminating the early Universe

Gamma-Ray Burst afterglows: illuminating the early Universe


Gamma-Ray Bursts (GRB) are brief and extremely bright flashes, caused by the death of a very massive star. The collision of the explosion with the surrounding interstellar medium (ISM) causes an afterglow at all wavelengths (radio to X-rays).

In the optical, spectroscopy of the afterglow allows to infer various properties of the ISM of the galaxy hosting the GRB: the metallicity, the neutral hydrogen gas column density, the dust and molecular hydrogen content, the level of ambient radiation and/or particle density and the kinematics of host-galaxy gas clouds and possible outflows (on both stellar and galactic scale).

I am currently leading a project that is collecting spectroscopy of a sample of GRB afterglows, which will allow - for the first time - study o f the interplay between the internal gas-physical properties mentioned above and the external properties (e.g. luminosity, colour, morphology) for a sample of high-redshift GRB host galaxies.

This proposal aims not only to continue this on-going work, but also to extend the investigation to higher redshifts, to the epoch of re-ionisation. After the Big Bang the Universe cooled down to become completely neutral, a period known as the Dark Ages. This dark period ended when the first stars and galaxies started to form and re-ionise the Universe, during the epoch of re-ionisation. Very little is known how this re-ionisation actually took place, and GRBs are one of the main probes of this important epoch in the history of the Universe.

This MC fellowship proposal will shed light on the epoch of re-ionisation through observations of high-redshift GRB afterglows. The investigation is to be performed at the University of Copenhagen, the proposed host institute, in the very active GRB group of Jens Hjorth. Prof. Hjorth¿s group is at the forefront of GRB science, and will have guaranteed access to the upcoming X-shooter instrument, which is perfectly suited for observations of very-high-redshift GRBs.

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NØRregade 10
Copenhagen K


Administrative Contact

Jens HJORTH (Prof.)

Project information

Grant agreement ID: 41363

  • Start date

    15 July 2007

  • End date

    14 July 2009

Funded under:


Coordinated by: