This loads a font easier to read for people with dyslexia.
This renders the document in high contrast mode.
This renders the document as white on black
This can help those with trouble processing rapid screen movements.
The Australia Telescope National Facility Colloquium
Mon 24 Apr to Mon 24 Apr 2017

Johannes Buchner

Johannes Buchner colloquium: A high-energy view of the galaxy-scale metal gas at z=0.5-3

At the peak of star formation (z=0.5-3), an important yet hard-to-constrain measurable is the metal gas content of galaxies, a side-product of the evolution of massive stars, and the origin of rocky planets like the earth. At the same time, high-energy source (AGN, GRB) emission is absorbed by this gas along the observers line-of-sight. Therefore it could be interesting to indirectly do galaxy tomography with these column densities. We performed a survey of afterglow obscuration of all Swift-detected
gamma-ray bursts (GRB), studying selection biases and advancing analysis
methodology. While we find little redshift evolution, a clear correlation of host stellar mass and metal column density is revealed. A simple geometrical model explains the width and shape of the column density distribution and the trend with galaxy mass correlation. Our results implicate the host's galaxy-scale metal gas as the dominant obscurer. From a galaxy evolution perspective, our study places new independent
constraints on the metal gas mass inside galaxies at z=0.5-4. We compare these with modern cosmological simulations (Illustris and EAGLE) and discuss implications for the obscuration of other sources inside high redshift galaxies, such as active galactic nuclei (AGN).


Contact

Shi Dai
shi.dai@csiro.au

Other Colloquia
What's On