SPECTRAL LAGS AND THE LAG-LUMINOSITY RELATION: AN INVESTIGATION WITH SWIFT BAT GAMMA-RAY BURSTS

Journal Article · Wed Mar 10 04:00:00 EST 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/711/2/1073· OSTI ID:21394313

Ukwatta, T N; Dhuga, K S; Eskandarian, A; Maximon, L C; Parke, W C ^[1]; Stamatikos, M; Sakamoto, T; Barthelmy, S D; Gehrels, N ^[2]; Norris, J P ^[3]

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1. George Washington University, Washington, DC 20052 (United States)
2. NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
3. Department of Physics and Astronomy, University of Denver, 2112 East Wesley Avenue, Room 211, Denver, CO 80208 (United States)

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. reported a correlation between the spectral lag and the isotropic peak luminosity of GRBs based on a limited sample. More recently, a number of authors have provided further support for this correlation using arbitrary energy bands of various instruments. In this paper, we report on a systematic extraction of spectral lags based on the largest Swift sample to date of 31 GRBs with measured redshifts. We extracted the spectral lags for all combinations of the standard Swift hard X-ray energy bands: 15-25 keV, 25-50 keV, 50-100 keV, and 100-200 keV and plotted the time dilation corrected lag as a function of isotropic peak luminosity. The mean value of the correlation coefficient for various channel combinations is -0.68 with a chance probability of {approx}0.7 x 10{sup -3}. In addition, the mean value of the power-law index is 1.4 +- 0.3. Hence, our study lends support to the existence of a lag-luminosity correlation, albeit with large scatter.

• OSTI ID: 21394313
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 711; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
BOSONS
COSMIC GAMMA BURSTS
COSMIC RADIATION
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ENERGY RANGE
HARD X RADIATION
IONIZING RADIATIONS
KEV RANGE
KEV RANGE 10-100
LUMINOSITY
MASSLESS PARTICLES
OPTICAL PROPERTIES
PHOTONS
PHYSICAL PROPERTIES
PRIMARY COSMIC RADIATION
RADIATIONS
RED SHIFT
X RADIATION