A T N F    D a i l y    A s t r o n o m y    P i c t u r e

24th of April 2017
ATNF Colloquium
A high-energy view of the galaxy-scale metal gas at z=0.5-3
by Johannes Buchner (Universidad Catolica, Chile)
Abstract. 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).

<<   |   archive   |   about   |   today   *   ATNF   |   Parkes   |   ATCA   |   Mopra   |   VLBI   |   ASKAP   |   >>