1. Unusual sites of GRBs in their host galaxies Lise Christensen
ESO, Chile
Work done with:
Paul Vreeswijk
Jesper Sollerman
Christina Thoene
Klaas Wiersema
Emeric Le Floc’h
HST images of Typical hosts of long duration bursts at z~1
(Fruchter et al 2006)

2. Host of GRB 980425 - SN 1998 bw (z=0.0085) FORS BVR VIMOS cube
30” = 5 kpc
SN region
Compare with archive data:
Magnitudes and Colours have to match Broad band data
Extracted narrow band IFU image has to match narrow band images
IFU extracted spectra have to match Long slit spectra

3. Location of the GRB from HST/STIS
WR region
SN region

4. Derived properties:
Ha emission line fit - > velocity map -> dynamic mass
Ha flux -> SFR, Specific SFR <- 24 m Spitzer image
Ha flux / continuum -> Ha EW -> age
Ha/Hb -> reddening E(B-V)
Flux ratios [OIII]/Hb / [NII]/HaOxygen abundance
Each spectrum > stellar population fitting -> stellar mass,age
12+log(O/H)
Christensen et al 2008

5. unusual emission line ratios?
Dopita et al. 2006