Transcript ppt

A. de Ugarte Postigo, I. Horvath , P. Veres , Z. Bagoly ,
L. G. Balazs , D. A. Kann , C. C. Thöne , P. D’Avanzo,
M.A. Aloy , S. Campana , S. Foley , J. Mao , S. Covino,
A. J. Castro-Tirado, J. P. U. Fynbo , J. Gorosabel ,
P. Jakobsson , L. Amati , and M. Nardini
Sample and classification
 Classification by Horváth
et al. (2010). Clustering
analysis.
 First 4 years of Swift.
 Burst with redshift (136):
 12 short
 28 intermediate
 82 long
 Contamination is
significant!
Redshift distribution
 Median redshift:
 0.46 for short
 1.33 for intermediate
 2.05 for long
 K-S test:
 Short-long: 0.0004%
 Short-interm.: 0.6%
 Interm.-long: 7%
Afterglow luminosity: X-ray
 K-S test at 100 sec:
 Short-Interm.: 2.2%
 Short-Long: 0.02%
 Interm.-Long: 0.003%
 K-S test at 104 sec:
 Short-Interm.: 0.13%
 Short-Long: 0.003%
 Interm.-Long: 0.002%
Afterglow luminosity: Optical
 K-S test at 100 sec:
 Interm.-Long: 11%
 K-S test at 104 sec:
 Interm.-Long: 3.3%
Dark bursts
 Intermediate: 5 out of
32 are dark (16%).
 Long: 27 out of 90 are
dark (30%).
 K-S test with only
detections give 4.6% of
coming from the same
population.
Hydrogen column density
 X-ray: Intermediate
bursts similar to long:
 K-S test gives 5.1%
 Optical: Small amount of
data to do statistics.
There is no clear trend.
Optical extinction
 Same distribution as for
long bursts.
 K-S test gives 61%
probability of coming
from the same
population.
Epeak vs. Eiso correlation
 Valid for long GRBs
but not for short
 Mostly valid for
intermediate bursts.
 Slight trend to find
them above the fit
Spectral lags
 Short have negligible
lags, while intermediate
and long tend to positive
lags.
 K-S test:
 Short-Long: 0.017%
 Short-Interm.: 0.009%
 Interm.-Long: 77%
Conclusions
 Intermediate GRBs are similar to long GRBs in:
 Spectral lags
 Epeak vs. Eiso correlation
 Similar intrinsic extinction
 But they differ in other aspects:
 Afterglow luminosity (specially in X-rays)
 Slightly lower redshifts
 More long dark bursts
 Differences with short bursts are more significant
 Same progenitor as long bursts but with slightly
different conditions
Thanks!!!