Observations of XRF afterglows and host galaxies

I will review the results of X-ray and optical observations of the afterglows and host galaxies of several X-ray Flashes. These include the two XRFs with confirmed spectroscopic redshifts, XRF 020903 (z=0.25) and XRF 030429 (z=2.66) and the well sampled afterglow of XRF 030723. I will compare the properties of these afterglows with the expectations that XRFs are the result of ``classical" GRBs which are viewed off the primary collimation axis.

I will also discuss the relationship between XRFs and supernovae. The discovery of a relationship between the peak energy of the prompt emission of a burst and its total isotropic energy release implies that XRFs should lie at typically lower redshifts and hence be ideal testbeds for the study of assocaited supernovae. I will present the results of SN searches in several XRF afterglows and show that while some (e.g XRF 030723 & 020903) do show evidence for associated supernovae others have no apparent supernovae to deep limits.

Finally I will also present the results from IR observations of the first Swift XRF - 050215B, whose afterglow was the faintest ever seen at comparable epochs (K>20 at t=9 hours).

This research is supported by PPARC, UK