Photometric redshifts for GRB afterglows from GROND and Swift/UVOT

Understand

We present a framework to obtain photometric redshifts (photo-zs) for gamma-ray burst afterglows.

• Using multi-band photometry from GROND and Swift/UVOT, photo-zs are derived for five GRBs for which spectroscopic redshifts are not available.
• We use UV/optical/NIR data and synthetic photometry based on afterglow observations and theory to derive the photometric redshifts of GRBs and their accuracy.
• Taking into account the afterglow synchrotron emission properties, we investigate the application of photometry to derive redshifts in a theoretical range between z~1 and z~12.