1. Paolo D’Avanzo (INAF-Osservatorio Astronomico di Brera);
The afterglow and host galaxy of GRB : evidence for a Ly-α emitter at z = 4.65
Paolo D’Avanzo (INAF-Osservatorio Astronomico di Brera);
in collaboration with:

2. GRB 090205 No UVOT detection @ t-t0 = 92 s T90 = 8.8 ± 1.8 s
keV
T90 = 8.8 ± 1.8 s
Perri et al. 2009, GCN 8884
Cummings et al. 2009, GCN 8886
keV
Perri et al. 2009, GCN 8884
Evans et al. 2009, GCN 8885
Perri & Stratta, 2009, GCN 8891
No UVOT t-t0 = 92 s
Perri et al. 2009, GCN 8884
Landsman & Perri, 2009, GCN 8893

3. GRB 090205 t-t0 ~ 7 h RAB ~ 22.3; IAB ~ 20.8 F(t) t -α ; α ~ 1.4
(D’Avanzo et al. 2009;, GCN 8887)
F(t) t -α ; α ~ 1.4

4. GRB 090205 t-t0 ~ 7 h RAB ~ 22.3; IAB ~ 20.8 F(t) t -α ; α ~ 1.4
(D’Avanzo et al. 2009;, GCN 8887)
F(t) t -α ; α ~ 1.4
z =4.65
(Thoene et al. 2009, GCN 8889;
Fugazza et al. 2009, GCN 8892)

5. GRB 090205 afterglow tb,1 tb,2 complex X-ray AG: brightening
at ~T0+1000s and flaring activity α2
ГX,2
F(t) t -α
α1 ~ 1.4; α2 ~ -1.7; α3 ~ 1.2;
Time resolved X-ray spectroscopy: absorbed power-law with
ГX,1~ ГX,2~ ГX,3~ 2.0
Galactic NH ~ 8 x 1020 cm-2
(no evidence for intrinsic absorbtion; NH < 3.5 x 1022 cm-2) α1
ГX,1 α3
ГX,3
X-ray and optical AG explained within the standard FS model with νc,νm < νopt and νX
X-ray “brightnening” possibly due to energy injection into the FS by the engine

6. GRB 090205: classification T90,rf = 1.6s Lag(Ch2-Ch1): -15 +/- 867 ms
Ch1 = keV
Ch2 = keV
Ch3 = keV
Ch4 = keV
Eγ,iso = (7.86 ± 1.21)x 1051 erg
Ep,i = 192 ± 85 keV

7. GRB 090205: classification T90,rf = 1.6s Lag(Ch2-Ch1): -15 +/- 867 ms
Ch1 = keV
Ch2 = keV
Ch3 = keV
Ch4 = keV
Eγ,iso = (7.86 ± 1.21)x 1051 erg
Ep,i = 192 ± 85 keV
(Antonelli et al. 2009)
GRB
Consistent with the
Ep,i - Eγ,iso
correlation
(Amati et al. 2008)

8. GRB 090205: evidence for a LAE (I)

9. GRB 090205: evidence for a LAE (I)
Lyman-α emission line

10. GRB 090205: evidence for a LAE (II)
Lyman-α emission line
0.4” offset with respect to the continuum
(3 z=4.65)
The same offset is found in imaging frames
Ly-α emission from the host galaxy
Farthest GRB host galaxy spectroscopically confirmed

11. GRB 090205 host galaxy τ < 150 Myr LLy-α ~ 0.6-0.7 L*
SFR ~ 4.2 MSun/yr
Z ≥ 0.27 ZSun
τ < 150 Myr
M* < 150 MSun

12. GRB 090205: conclusions D’Avanzo et al., A&A submitted
optical afterglow and host galaxy discovery; redshift determination
complex X-ray AG: brightening at ~T0+1000s and flaring activity
rest frame short duration (1.6s), but likely long, of massive stellar collapse origin
the host galaxy is a z = 4.65
SFR ~ 4.2 MSun/yr
young stellar population (< 150 Myr)
high metallicity (Z ≥ 0.27 ZSun)
farthest GRB HG spectroscopically confirmed
GRBs as one of the most effective way, complementary to surveys, to study the high-z Universe
D’Avanzo et al., A&A submitted