IFU studies of GRBs and SNe regions Lise Christensen (Excellence Cluster Universe, Technical University Munich) + Maryam Modjaz (NY), + Christina Thoene (IAA, Granada), + Susanna Vergani (INAF, Brera) + Aybuke Yoldas (IOA, Cambridge)
What makes a GRB? Fireball model
GRBs/SNe connection Hjorth et al Bloom et al SN bump Type Ic
Core collapse explosion types Type II : + H Type Ib : - H + He Type Ic : - H - He - Si binary mass transfer? Type Ic broad lined (hypernova): - H – He E kin >10 52 erg (model dependent) line widths: ~ km/s no GRB GRB / Ic –bl : metal poor : < 10% solar, fast rotating GRB/ no SN Ic –bl ( SN detections are the exception – Fynbo+ 2006) Yoon et al. 2006
What makes a GRB/ hypernova? – We never spotted a progenitor of a Type Ib/c SN Clues from their hosts: Progenitor star mass Stellar population age Metallicity proximity to HII regions Host galaxy studies
HST images of hosts of long duration bursts at z=1 (Fruchter et al 2006)
Redshift/host magnitude distribution Jakobsson et al. 2010
Host of GRB SN 1998 bw (z=0.0085) FORS BVRVIMOS cube Compare IFU- with archive data: Magnitudes and colours have to match broad band data Extracted narrow band IFU image has to match Ha narrow band images IFU extracted spectra have to match long slit spectra 30” = 5 kpc HST WFPC
GRB host: Derived properties Christensen et al 2008 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 GRB region is not so unusual 12+log(O/H)
GRB (z=0.08) VIMOS cubeFORS - R Thoene et al GRB site: No SN detected young: 6 Myrs = 32 M star metal poorer than the galaxy (slit spectra) progenitor likely a massive star
Unusual emission line ratios? Models: Dopita et al B E(B-V)=0.5, solar metallicity
Metallicities In GRB/SNe regions Modjaz et al. 2008
GRB – SN connections Modjaz et al But disagrees with Anderson et al Kelly et al 2008 Metallicity distribution SN/GRB location in host
NGC 6754: 4 SNe in 10 years NICMOS,F110W, FOV~50” Type Ia Type II Type Ia N
Old: 30-40% level detector fringes New: ~10% IFU fringes in some spectra (also present In old data) New VIMOS detectors
New VIMOS detector sensitivities Q1 Q2 Q3 Q4 old new
Future studies of SNe hosts Type Ic / Ic –bl (without GRBs) Targeted / non-targeted galaxies Sample of ~ 20 galaxies (Current status: applied for observations) M B = -21 to -18
Ongoing studies of GRB hosts VLT IFU programmes: Low-z hosts with Sinfoni + AO : High spatial resolution on four closest hosts Stellar population in the GRB site ~100 pc (Z, age, mass) (PI: A. Yoldas) High-z : Sinfoni – No AO: locate galaxies in line of sight (Mg II absorbers) faint emission from GRB hosts (PI: S. Vergani) GRB (z=2.33) [O III] 5007
Summary Aim: to distinguish GRB and SN regions from host studies Systematic differences in metallicity between GRB and SNe Unusual regions in hosts – maybe for GRBs, but unknown for SNe Ic’s Only looked systematically at HII region emission lines (GRB/SNe) Underlying stellar populations to be investigated (GRB/SNe) Upgrade of VIMOS detectors is promising for future studies
z=0.08 shortish duration: 4s no SN detected in lightcurve at very deep limits (nor with spectroscopy) Located in large star-forming region GRB questioning the GRB-SN connection
Higher spectral resolution Flames- ARGUS archive data R~10000 Courtesy: M. Dessauges-Zavadsky + F. Hammer
Modjaz et al Global metallicity in SN hosts