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Spectral Lags and the Lag-Luminosity Relation: An Investigation with Swift BAT Gamma-ray Bursts
T. N. Ukwatta, M. Stamatikos, K. S. Dhuga +7
Spectral lag, the time difference between the arrival of high-energy and low-energy photons, is a common feature in Gamma-ray Bursts (GRBs). Norris et al. 2000 reported a correlati…
Variability in the Prompt Emission of Swift-BAT Gamma-Ray Bursts
T. N. Ukwatta, K. S. Dhuga, W. C. Parke +8
We present the results of our study of the variability time scales of a sample of 27 long Swift Gamma-Ray Bursts (GRBs) with known redshifts. The variability time scale can help ou…
A glimpse of the end of the dark ages: the gamma-ray burst of 23 April 2009 at redshift 8.3
N. R. Tanvir, D. B. Fox, A. J. Levan +59
It is thought that the first generations of massive stars in the Universe were an important, and quite possibly dominant, source of the ultra-violet radiation that reionized the hy…
The Correlation of Spectral Lag Evolution with Prompt Optical Emission in GRB 080319B
Michael Stamatikos, Tilan N. Ukwatta, Takanori Sakamoto +8
We report on observations of correlated behavior between the prompt gamma-ray and optical emission from GRB 080319B, which confirm that (i) they occurred within the same astrophysi…
Investigating the Possibility of Screening High-z GRBs based on BAT Prompt Emission Properties
T. N. Ukwatta, T. Sakamoto, K. S. Dhuga +5
Being able to quickly select among gamma-ray bursts (GRBs) seen by the Swift satellite those which are high-z candidates would give ground-based observers a better chance to determ…
Spectral Lags of Gamma-Ray Bursts from Primordial Black Hole (PBH) Evaporations
T. N. Ukwatta, J. H. MacGibbon, W. C. Parke +5
Primordial Black Holes (PBHs), which may have been created in the early Universe, are predicted to be detectable by their Hawking radiation. PBHs with an initial mass of 5.0 * 10^1…